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Predicting individual differences in distractibility Aks, Deborah June 1988

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PREDICTING INDIVIDUAL DIFFERENCES IN DISTRACTIBILITY by Deborah June Aks B.A., The State U n i v e r s i t y of New York at Binghamton, N.Y., 1984 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS i n THE FACULTY OF GRADUATE STUDIES DEPARTMENT OF PSYCHOLOGY We accept t h i s t h e s i s as conforming to the r e q u i r e d standard The U n i v e r s i t y of B r i t i s h Columbia December, 1988 © Deborah June Aks, 1988 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. The University of British Vancouver, Canada Department DE-6 (2/88) i i A b s t r a c t L i t t l e i s known about what makes one i n d i v i d u a l d i s t r a c t i b l e while another i s not. T h i s study approaches t h i s problem by a s s e s s i n g the e f f e c t i v e n e s s of v a r i o u s p e r s o n a l i t y , a r o u s a l , i n t e l l i g e n c e and s u b j e c t i v e r e p o r t v a r i a b l e s as p r e d i c t o r s of how one w i l l respond to the presence of d i s t r a c t o r s d u r i n g a speeded v i s u a l search ta s k . The i n a b i l i t y to screen out s t i m u l i which are independent of the t a r g e t e d task d e f i n e s d i s t r a c t i b i l i t y . The search task used here, i n v o l v i n g item matching under speeded c o n d i t i o n s , was administered t o 308 s u b j e c t s under v i s u a l and a u d i t o r y d i s t r a c t o r c o n d i t i o n s . Each p r e d i c t o r of d i s t r a c t i b i l i t y i s t r e a t e d as a separate subexperiment f o r purposes of c l a r i t y . Measures of s t a t e and t r a i t a r o u s a l as w e l l as s u b j e c t i v e r e p o r t s of d i s t r a c t i b i l i t y were i n e f f e c t i v e p r e d i c t o r s of s u s c e p t i b i l i t y to d i s t r a c t i b i l i t y . The r e s u l t s were more encouraging f o r s p e c i f i c p e r s o n a l i t y and i n t e l l i g e n c e v a r i a b l e s which turned out to be e f f e c t i v e p r e d i c t o r s of d i s t r a c t i b i l i t y . These f i n d i n g s i n d i c a t e t h a t the prototype of a d i s t r a c t i b l e i n d i v i d u a l i s one who tends to be higher i n obsessive/compulsive and Type A behavior p a t t e r n s and lower i n i n t e l l i g e n c e . i i i Table of Contents T i t l e Page i A b s t r a c t i i Table of Contents i i i L i s t of Tables v i L i s t of F i g u r e s v i i Acknowledgements v i i i Chapter 1: I n t r o d u c t i o n 1 Chapter 2: The d i s t r a c t i o n task .9 Is d i s t r a c t i o n g e n e r a l i z a b l e ? 9 The makings of a d i s t r a c t o r 15 Method 18 The d i s t r a c t i o n t e s t 18 R e s u l t s & D i s c u s s i o n 21 Chapter 3: S u b j e c t i v e r e p o r t of d i s t r a c t a b i l i t y : A p r e d i c t o r of d i s t r a c t i b i l i t y ? 26 Method 28 Stimulus S e l e c t i v i t y Inventory 28 R e s u l t s & D i s c u s s i o n ....31 iv Chapter 4: A r o u s a l : A p r e d i c t o r of d i s t r a c t i b i l i t y ? 35 Arousal d e f i n e d 35 P h y s i o l o g i c a l b a s i s of a r o u s a l 36 Varying responses to s t i m u l a t i o n : H a b i t u a t i o n and o r i e n t i n g response... 37 A r o u s a l , d i s t r a c t i o n & performance...39 Information r a t e - a r o u s a l theory....40 Response - a r o u s a l theory 41 Yerkes-Dodson law 41 Measuring a r o u s a l 43 Method 46 R e s u l t s & D i s c u s s i o n 47 Chapter 5: P e r s o n a l i t y : A p r e d i c t o r of d i s t r a c t i b i l i t y ? 51 E x t r a v e r s i o n / I n t r o v e r s i o n 51 Sensation Seeking 53 Obsessive/Compulsive behavior 54 Type A/ Type B p e r s o n a l i t y 55 Method 58 Eysenck P e r s o n a l i t y Inventory.... 59 Sensation Seeking Scale 59 Obsessive/Compulsive Inventory...61 Framingham Type A Inventory 61 R e s u l t s & D i s c u s s i o n 62 Chapter 6: I n t e l l i g e n c e : A p r e d i c t o r of d i s t r a c t i b i l i t y ? 66 Method 69 Wonderlic Personnel Test 70 Quick Test 71 S p e l l i n g Component Assessment 72 R e s u l t s & D i s c u s s i o n . ....73 Chapter 7: Conclusions 76 S u b j e c t i v e impressions versus a c t u a l d i s t r a c t i b i l i t y 76 S u b j e c t i v e p e r c e p t i o n of d i s t r a c t i b i l i t y 79 Summary c o n c l u s i o n s 80 References 82 Appendix A: The D i s t r a c t i o n T e s t 98 Appendix B: Stimulus S e l e c t i v i t y Inventory 112 Appendix C: Thayer A r o u s a l S e l f - R e p o r t 118 v i L i s t of Tables Table 1: Group performance on the d i s t r a c t i o n test...22 Table 2: Stimulus s e l e c t i v i t y and d i s t r a c t i b i l i t y -Pearson C o r r e l a t i o n s 32 Table 3: Arousal and the d i s t r a c t i o n task -Pearson C o r r e l a t i o n s 48 Table 4: D i s t r a c t i b i l i t y and a r o u s a b i l i t y -Pearson C o r r e l a t i o n s 49 Table 5: P e r s o n a l i t y and d i s t r a c t i b i l i t y -Pearson C o r r e l a t i o n s 62 Table 6: I n t e l l i g e n c e and number c o r r e c t Pearson C o r r e l a t i o n s 73 Table 7: G e n e r a l i z e d p r o f i c i e n c y a c r o s s c o n d i t i o n s of the d i s t r a c t i o n task -Pearson C o r r e l a t i o n s ( s t a n d a r d i z e d scores)..74 Table 8: I n t e l l i g e n c e and s t a n d a r d i z e d d i s t r a c t i b i l i t y measures - Pearson C o r r e l a t i o n s 74 Table 9: M u l t i p l e r e g r e s s i o n / Stepwise -V i s u a l d i s t r a c t i b i l i t y A u d i t o r y d i s t r a c t i b i l i t y General d i s t r a c t i b i l i t y 77 Table 10:Stimulus s e l e c t i v i t y i n v e n t o r y and p e r s o n a l i t y - Pearson C o r r e l a t i o n s 79 v i i L i s t of F i g u r e s F i g u r e 1: Task e x t r i n s i c and i n t r i n s i c d i s t r a c t o r s . . . 1 6 F i g u r e 2: Sample items from the d i s t r a c t i o n t e s t without d i s t r a c t o r s present 18 F i g u r e 3: Sample items from the d i s t r a c t i o n t e s t with d i s t r a c t o r s present 20 F i g u r e 4: Pre and post t e s t a r o u s a l s e l f r e p o r t Experimental and c o n t r o l groups 48 v i i i Acknowledgements There are a number of i n d i v i d u a l s who deserve c r e d i t f o r h e l p i n g me through the harrowing moments of my t h e s i s e xperience. I would l i k e to thank my a d v i s o r S t a n l e y Coren f o r h i s endless supply of a t t e n t i o n and a s s i s t a n c e . Some of Stan's g r e a t e s t c o n t r i b u t i o n s to t h i s academic endeavor, i n c l u d e t e a c h i n g me the meaning of c l a r i t y , c r e a t i v i t y , s c i e n t i f i c e x p l o r a t i o n , and h u m i l i t y . I am g r a t e f u l t o Peter Suedfeld f o r a thorough review of a p r e l i m i n a r y d r a f t of t h i s t h e s i s , as w e l l as f o r t e a c h i n g me the a r t of being meticulous i n r e s e a r c h . I would a l s o l i k e t o thank Lawrence Ward f o r h i s w i l l i n g n e s s to serve on my M.A. committee as w e l l as f o r h i s i n s i g h t f u l comments. And thanks a m i l l i o n to Aaron f o r h e l p i n g me remain sane through i t a l l . P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 1 Chapter 1 I n t r o d u c t i o n "My experience i s what I (agree to) a t t e n d t o . Only those items which I n o t i c e , shape my mind" (James, 1890 p.402). The i m p l i c a t i o n of James' quote i s t h a t d i f f e r e n t o r i e n t a t i o n s i n a t t e n t i o n are r e s p o n s i b l e for d i f f e r e n t phenomenal experiences. T h i s l i n k between a t t e n t i o n and experience w i l l be examined i n terms of d i s t r a c t i o n and v a r i o u s p s y c h o l o g i c a l measures that may p r e d i c t d i s t r a c t i b i l i t y . These measures in c l u d e a s e l f - r e p o r t of d i s t r a c t i b i l i t y , a r o u s a b i l i t y , as w e l l as measures of p e r s o n a l i t y and i n t e l l i g e n c e . In essence, the main focus of t h i s t h e s i s i s to i n v e s t i g a t e and p r e d i c t i n d i v i d u a l d i f f e r e n c e s i n d i s t r a c t i b i l i t y . In t h i s study, d i s t r a c t i b i l i t y r e f e r s to the i n a b i l i t y to screen out i r r e l e v a n t s t i m u l i i n a task. I t manifests i t s e l f i n impaired performance i n tasks i n which r e l e v a n t s t i m u l i must be processed i n the presence of ambient i r r e l e v a n t s t i m u l i ( d i s t r a c t o r s ) . Viewed from models of a t t e n t i o n , d i s t r a c t i b i l i t y i s c h a r a c t e r i z e d by a l o s s of f o c a l i z a t i o n and c o n c e n t r a t i o n of consciousness (Norman, 1975). Since a t t e n t i o n i s more f r e q u e n t l y s t u d i e d than d i s t r a c t i o n , we w i l l begin with a d i s c u s s i o n of some d e f i n i t i o n s and t h e o r i e s used i n a t t e n t i o n a l t h e o r i e s that are r e l e v a n t to the present problem. P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 2 According to Hebb (1955), a t t e n t i o n i s a h y p o t h e t i c a l process s i m i l a r to a neural a s s o c i a t i o n that produces s e l e c t i v i t y . S u c c e s s f u l s e l e c t i o n i s , of course, the opposite of d i s t r a c t i o n . " S e l e c t i v i t y of a t t e n t i o n i n v o l v e s the problem of which items of incoming information w i l l occupy the organism's l i m i t e d i n f o r m a t i o n - t r a n s m i t t i n g c a p a c i t y " (Meldman, 1970, p.200) . "Conc e n t r a t i o n and f o c u s i n g of mental e f f o r t c h a r a c t e r i z e s a t t e n t i o n ; i t i s a focus t h a t i s s e l e c t i v e , s h i f t a b l e and d i v i s i b l e " (Best, 1986, p.36). From the above i t should be c l e a r t h a t one common feature of most d e f i n i t i o n s of a t t e n t i o n i n v o l v e s s t i m u l u s s e l e c t i v i t y i n the sense t h a t what is attended t o should be the only m a t e r i a l in consc i o u s n e s s , with unattended s t i m u l i screened out. Th i s c h a r a c t e r i s t i c i s di s c u s s e d below i n the context of models of a t t e n t i o n t h a t can provide p o t e n t i a l e x p l a n a t i o n s as to why people d i f f e r i n t h e i r degree of d i s t r a c t i b i l i t y or the (lack of) a b i l i t y t o screen out extraneous s t i m u l i . T h i s w i l l be a l i m i t e d review, f o c u s i n g on those models of a t t e n t i o n that s p e c i f y the mechanism of stimulus s e l e c t i v i t y and that seem to bear d i r e c t l y on the problem of d i s t r a c t i b i l i t y . The e a r l i e r models of a t t e n t i o n i n c l u d e Broadbent's f i l t e r t h eory (1958), Treisman's a t t e n u a t i o n t h e o r y (1964) and Deutsch and Deutsch's Late S e l e c t i o n Theory (1963) of a t t e n t i o n . These P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 3 t h e o r i e s propose t h a t a s e l e c t i v e d e v i c e l i k e a f i l t e r or a b o t t l e n e c k e x i s t s at some point i n i n f o r m a t i o n p r o c e s s i n g . Messages in r e j e c t e d channels are f i l t e r e d out somewhere i n the p e r c e p t u a l or c o g n i t i v e process. Where t h i s stimulus s e l e c t i o n occurs i s one d i s t i n g u i s h i n g f e a t u r e of these d i f f e r e n t t h e o r i e s . D i f f e r e n c e s i n the f i l t e r ' s e f f e c t i v e n e s s , r e g a r d l e s s of l o c a t i o n , can induce d i f f e r e n c e s i n d i s t r a c t i b i l i t y . For example, the f i l t e r of a n o n - d i s t r a c t i b l e person might be c h a r a c t e r i z e d as being p r o f i c i e n t i n s e l e c t i n g and s c r e e n i n g out i r r e l e v a n t s t i m u l i , while a d i s t r a c t i b l e i n d i v i d u a l can be d e s c r i b e d as having an i n e f f i c i e n t or i n d i f f e r e n t f i l t e r . U n f o r t u n a t e l y these models do not s p e c i f y what i n d i v i d u a l c h a r a c t e r i s t i c s are a s s o c i a t e d with e f f i c i e n t versus i n e f f i c i e n t f i l t e r s . Other a t t e n t i o n a l models which may provide i n s i g h t i n t o what d i s t i n g u i s h e s a d i s t r a c t i b l e person from a n o n - d i s t r a c t i b l e person are those t h a t are " c a p a c i t y " or "resource" based. Rather than having a t t e n t i o n d e f i n e d i n terms of competition between separate f i l t e r s or a n a l y z e r s , Kahneman (1973) proposed a p a r a l l e l p r o c e s s i n g model of a t t e n t i o n i n which a t t e n t i o n i s viewed as a s e t of c o g n i t i v e processes t h a t c a t e g o r i z e and r e c o g n i z e s t i m u l i . These processes, or " c o g n i t i v e resources", are l i m i t e d . A t t e n t i o n a l l i m i t s are imposed because we only have a f i n i t e amount of our mental re s o u r c e s to apply to any p e r c e p t u a l t a s k . V a r i a t i o n s i n these l i m i t s may be r e s p o n s i b l e f o r i n d i v i d u a l d i f f e r e n c e s i n d i s t r a c t i b i l i t y . An example of P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 4 such a l i m i t a t i o n appears i n Kahneman's (1973) argument that "the c o g n i t i v e system f e a t u r e s a stage i n which resources are a l l o c a t e d to process incoming s t i m u l i . T h i s a l l o c a t i o n process i s f l e x i b l e and under our c o n t r o l " (Kahneman, 1973 p.42). We can i n f e r from t h i s t h a t a g r e a t e r r e s o u r c e c a p a c i t y and/or gre a t e r c o n t r o l of e x i s t i n g r e s o u r c e s , are a s s o c i a t e d with a n o n - d i s t r a c t i b l e i n d i v i d u a l . Such resource c a p a c i t y might manifest i t s e l f as a memory b u f f e r , i n c r e a s e d speed of p r o c e s s i n g or other i n t e l l i g e n c e r e l a t e d or c o g n i t i v e e f f i c i e n c y r e l a t e d f a c t o r s . Another approach to the study of a t t e n t i o n i s i n terms of e x c i t a t i o n of r e l e v a n t inputs and I n h i b i t i o n of i r r e l e v a n t i n p u t s . T h i s group of t h e o r i e s argue t h a t a l l s t i m u l i are attended t o , to some extent ( N e i l l , 1977; E r i k s e n & S c h u l t z , 1979; Posner, Snyder & Davidson, 1980; Treisman & Gelade, 1980; Broadbent, 1982; T i p p e r , 1985). A c c o r d i n g to the commonly employed s p o t l i g h t analogy (Broadbent, 1982; Posner, Snyder & Davidson, 1980; Treisman & Gelade, 1980) a t t e n t i o n i s d i r e c t e d l i k e a beam of l i g h t moving i n space. P r o c e s s i n g of s t i m u l i w i t h i n t h i s beam i s f a c i l i t a t e d . In c o n t r a s t , i n h i b i t o r y based t h e o r i e s argue that the i r r e l e v a n t input needs to be suppressed ( N e i l l , 1977; E r i k s e n & S c h u l t z , 1979; T i p p e r , 1985). In other t h e o r i e s , i n t e r n a l r e p r e s e n t a t i o n s of ignored o b j e c t s might p a s s i v e l y decay to r e s t i n g l e v e l s i n unused channels (Deutsch & Deutsch, 1963; Van Der Heuden, 1981; A l l p o r t , Tipper & Chimel, 1985). While o f f e r i n g no s p e c i f i c mechanisms a l l of these P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 5 t h e o r i e s suggest t h a t a d i s t r a c t i b l e i n d i v i d u a l i s one who i s d e f i c i e n t i n f a c i l i t a t i n g the p r o c e s s i n g of r e l e v a n t inputs or i n h i b i t i n g i r r e l e v a n t input. Whether d i s t r a c t i b i l i t y i s a f u n c t i o n of an e x c i t a t o r y f o c u s i n g process, an i n h i b i t i n g process or a decay process i s open to debate and w i l l not be r e s o l v e d here, however e x c i t a t i o n and i n h i b i t i o n are i n d i v i d u a l d i f f e r e n c e v a r i a b l e s which may be i n d i r e c t l y measured by performance. For example, by p l a c i n g the i n h i b i t o r y models i n the context of i n d i v i d u a l d i f f e r e n c e s , B u l l e n & Hemsley (1984) suggested t h a t a d e f i c i t i n i n h i b i t o r y mechanisms i n in f o r m a t i o n p r o c e s s i n g e x i s t s i n d i s t r a c t i b l e i n d i v i d u a l s . I t i s important t o recognize t h a t these d i f f e r e n t models do provide f o r the p o s s i b i l i t y t h a t i n d i v i d u a l s w i l l d i f f e r i n terms of t h e i r a b i l i t y to focus a t t e n t i o n , hence i n terms of t h e i r d i s t r a c t i b i l i t y . U n f o r t u n a t e l y they are not very s p e c i f i c as to how one might d i s c r i m i n a t e between a d i s t r a c t i b l e and n o n - d i s t r a c t i b l e i n d i v i d u a l . Much i s t h e o r i z e d about a t t e n t i o n i n g e n e r a l , which might be u s e f u l i n our present problem. For example i f we ask an i n d i v i d u a l to process some s t i m u l i i n the presence of an i r r e l e v a n t context we may view t h i s task as a dual task a c t i v i t y : 1) Ignore the d i s t r a c t o r s and 2) S e l e c t the response which matches the t a r g e t . S e v e r a l t h e o r i e s make s p e c i f i c p r e d i c t i o n s about du a l task performance depending on the modality of p r e s e n t a t i o n . The modality i n t e r a c t i o n s are o f t e n complex; f o r i n s t a n c e , some t h e o r i e s suggest that performance P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 6 i n t e r f e r e n c e can occur i f the two t a s k s are presented i n the same modality and performance f a c i 1 i t a t i o n can occur i f the two tasks are presented i n separate m o d a l i t i e s (Wickens, 1984; E r i k s e n , 1985). Whether the modality of the d i s t r a c t o r and f o c a l stimulus are important d i f f e r s f o r s i n g l e versus m u l t i p l e resource models. In s i n g l e resource models, there i s only one pool of c o g n i t i v e p r o c e s s i n g c a p a c i t y a v a i l a b l e , hence a l l s t i m u l i , r e g a r d l e s s of source or modality, must draw upon the same re s o u r c e . T h i s would suggest that the m o d a l i t y of the task has no impact on performance of two t a s k s (Kahneman, 1973). According to the s i n g l e c a p a c i t y view we would not expect any d i f f e r e n c e i n performance between i n t e r and i n t r a modality t a s k s . Extending t h i s l o g i c to i n d i v i d u a l d i f f e r e n c e s i n d i s t r a c t i b i l i t y , i f the modality of the d i s t r a c t o r and task i s unimportant then d i s t i n g u i s h i n g between d i s t r a c t i b l e and n o n - d i s t r a c t i b l e i n d i v i d u a l s would depend o n l y on the s i z e of an i n d i v i d u a l ' s s i n g l e resource. T h i s suggests that d i s t r a c t i n g s t i m u l i w i l l have the same e f f e c t , r e g a r d l e s s of t h e i r source of i n p u t . In e f f e c t , we are saying t h a t when doing a v i s u a l task, f o r i n s t a n c e , a d i s t r a c t i b l e i n d i v i d u a l w i l l be e q u a l l y e f f e c t e d by v i s u a l and a u d i t o r y d i s t r a c t o r s . I f t h i s i s the case, then d i s t r a c t i b i l i t y may be viewed as a f a i r l y g e neral i n d i v i d u a l d i f f e r e n c e v a r i a b l e , perhaps h i g h l y c o r r e l a t e d across s i t u a t i o n s . In c o n t r a s t , the m u l t i p l e resource p e r s p e c t i v e (Norman & P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 7 Bobrow, 1975; Wickens, 1984) argues i n favor of m u l t i p l e pools of d i f f e r e n t i a t e d r e s o u r c e s ; with perhaps d i f f e r e n t degrees of d i s t r a c t i b i l i t y . Here performance i s p r e d i c t e d to be modality s p e c i f i c , where each modality behaves as a separate r e s o u r c e . The m u l t i p l e resource view expects g r e a t e r i n t e r f e r e n c e i n a t e s t which c o n t a i n s d i s t r a c t o r s of the same modality as the task. T h i s i n t e r f e r e n c e occurs because the task and d i s t r a c t o r s are consuming resources from the same p o o l . In a s i t u a t i o n where the task and d i s t r a c t o r s are i n d i f f e r e n t m o d a l i t i e s , they d e p l e t e separate p o o l s . When we apply t h i s m u l t i p l e resource reasoning to d i f f e r e n c e s i n d i s t r a c t i b i l i t y , i t suggests the p o s s i b i l i t y that d i s t r a c t i b i l i t y might be modality s p e c i f i c . Thus an i n d i v i d u a l with a l i m i t e d v i s u a l c a p a c i t y but a l a r g e a u d i t o r y p r o c e s s i n g c a p a c i t y might be very d i s t r a c t e d by v i s u a l inputs but show l i t t l e e f f e c t f o r i r r e l e v a n t a u d i t o r y s t i m u l i . The m u l t i p l e resource theory as i t s name suggests, would argue that d i s t r a c t i b i l i t y can be a m a n i f e s t a t i o n of l i m i t a t i o n s i n any one or a l l of the a t t e n t i o n a l r e s o u r c e s . Since the a t t e n t i o n a l models themselves do not provide much guidance as to why some i n d i v i d u a l s are d i s t r a c t i b l e and others are not, perhaps some v a r i a b l e s which are presumed to be r e l a t e d to a t t e n t i o n w i l l be more u s e f u l . For i n s t a n c e , Kahneman's theory i n c o r p o r a t e s a r o u s a l and e f f o r t i n t o the resource theory of a t t e n t i o n and we know that i n d i v i d u a l s do d i f f e r i n these domains. P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 8 The r a t i o n a l e behind t h i s t h e s i s w i l l be to look a t c l u s t e r s of v a r i a b l e s which, on general c o n s i d e r a t i o n seem to be r e l a t e d to a t t e n t i o n a l f a c t o r s and which, p r i m a - f a c i e , might be p r e d i c t o r s of i n d i v i d u a l d i f f e r e n c e s i n d i s t r a c t i b i l i t y . Each se t of v a r i a b l e s w i l l be introduced and j u s t i f i e d i n a separate chapter, s i n c e each c l u s t e r i s based upon d i f f e r e n t t h e o r e t i c a l and e m p i r i c a l bases. In t h i s e x p o s i t i o n then, for purposes of c l a r i t y , t e s t s of the a b i l i t y of these separate measures to p r e d i c t d i s t r a c t i b i l i t y w i l l be t r e a t e d as separate subexperiments. In essence, these measures c o n s t i t u t e an i n t e r l e a v e d s e t of experiments which u l t i m a t e l y w i l l inform us of which v a r i a b l e s are v a l i d p r e d i c t o r s of d i s t r a c t i b i l i t y and which are not. P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 9 Chapter 2 The D i s t r a c t i o n Task A fundamental assumption of t h i s t h e s i s i s that d i s t r a c t i b i l i t y , l i k e a t t e n t i o n , r e v e a l s i t s presence through i t s e f f e c t on behavior. Before we can begin to t e s t f o r v a r i a b l e s t h a t may p r e d i c t d i s t r a c t i b i l i t y we must f i r s t s e l e c t a task and determine a s e t of c o n d i t i o n s under which a reasonable number of i n d i v i d u a l s w i l l be d i s t r a c t e d with a consequent d e t e r i o r a t i o n of task performance. Broadbent, Broadbent & Jones (1986) demonstrated t h a t there i s a wide ch o i c e of t a s k s which can be used to measure d i s t r a c t i b i l i t y . I t i s t h i s v e r y m u l t i p l i c i t y of task o p t i o n s t h a t has created a c o n t r o v e r s y as to whether d i s t r a c t i b i l i t y g e n e r a l i z e s across d i f f e r e n t t a s k s and s i t u a t i o n s . Is D i s t r a c t i o n G e n e r a l i z a b l e ? Although the i s s u e of the extent to which d i s t r a c t i b i l i t y i s g e n e r a l i z a b l e i s not the primary focus of t h i s t h e s i s , as was mentioned i n the i n t r o d u c t o r y chapter, there i s some i n t e r e s t i n modality s p e c i f i c versus cross modality i n t e r a c t i o n s which may be t h e o r e t i c a l l y important. Here, we w i l l o n l y attempt to answer the q u e s t i o n "Does d i s t r a c t i o n to a u d i t o r y and v i s u a l d i s t r a c t o r s covary w i t h i n an i n d i v i d u a l ? " . As f a r as g e n e r a l i z a b i l i t y a c r o s s tasks and s i t u a t i o n s i s concerned, the P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 10 stance taken i n t h i s t h e s i s i s s i m i l a r to that of Sternberg (1982) and Hunt (1980), t h a t there i s some degree of g e n e r a l i z e d d i s t r a c t i b i l i t y a c r o s s d i f f e r e n t tasks and s i t u a t i o n s which accounts f o r i n d i v i d u a l d i f f e r e n c e s i n i n t e l l i g e n c e . A s i m i l a r assumption of g e n e r a l i z e d a t t e n t i o n e x i s t s i n c l i n i c a l l i t e r a t u r e p e r t a i n i n g to l e a r n i n g d i s a b i l i t i e s , h y p e r a c t i v i t y and a t t e n t i o n d e f i c i t d i s o r d e r s where each a t t e n t i o n d e f i c i t m anifests i t s e l f i n d i f f e r e n t tasks and s e t t i n g s and i n response to a v a r i e t y of d i f f e r e n t s t i m u l i (Douglas & P e t e r s , 1979; Douglas, 1983). C e r t a i n l y most a t t e n t i o n r e l a t e d a b i l i t i e s do g e n e r a l i z e , and d i s t r a c t i b i l i t y can be viewed here as a n o n - s p e c i f i c breakdown i n f o c a l a t t e n t i o n due to the i n a b i l i t y to screen out i r r e l e v a n t s t i m u l i . Before going f u r t h e r , l e t us c o n s i d e r data t h a t opposes t h i s premise by s u g g e s t i n g t h a t there i s l i t t l e g e n e r a l i z a b i 1 i t y of d i s t r a c t i b i l i t y . Consider a demonstration of how d i f f e r e n c e s i n the task d e s i g n seem to demand d i f f e r e n t a t t e n t i o n a l p rocesses. Broadbent et a l ' s (1986) r e s e a r c h i n t h i s area i n d i c a t e s t h a t many d i f f e r e n t measures of the q u a l i t y of a t t e n t i o n may e x i s t and t h a t i n d i v i d u a l s best on one are not n e c e s s a r i l y best on o t h e r s . Broadbent et a l made use of v a r i a t i o n s of E r i k s e n ' s c l a s s i c focused a t t e n t i o n task where a c h o i c e r e a c t i o n has to be made to a l e t t e r t h a t was an A or a B. In these f i l t e r t e s t s , the s p a t i a l l o c a t i o n of the t a r g e t s t i m u l u s was known i n advance so there was no need f o r the s u b j e c t to s e a r c h . On some t r i a l s i t was accompanied by other P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 11 d i s t r a c t i n g s t i m u l i , a l s o an A or a B, but s u b j e c t s were t o l d to ignore these. S p a t i a l p o s i t i o n was used as the cue to s e l e c t i n f o r m a t i o n and to r e j e c t i r r e l e v a n t s t i m u l i . Broadbent et a l a l s o used the same c h o i c e r e a c t i o n tasks to o b t a i n a measure of search e f f i c i e n c y . In t h i s c o n d i t i o n the t a r g e t s t i m u l u s l o c a t i o n was not known and consequently n o n - l e t t e r ( d i g i t ) d i s t r a c t o r s were used. Given these search c o n d i t i o n s the task was to f i n d a t a r g e t a t an unknown l o c a t i o n using the " c a t e g o r i c nature" of the t a r g e t to i d e n t i f y i t . Here the t a r g e t category was a l e t t e r and the d i s t r a c t o r category was a d i g i t . In t h i s s e r i e s of f i l t e r and s e a r c h experiments, Broadbent et a l found l i t t l e evidence f o r any g e n e r a l a b i l i t y to r e s i s t or be v u l n e r a b l e to d i s t r a c t i o n . Broadbent et a l (1986) attempted to j u s t i f y the i n c o n s i s t e n t performance of i n d i v i d u a l s u b j e c t s a c r o s s tasks by p o i n t i n g out the multitude of a t t e n t i o n a l v a r i a b l e s t h a t can be manipulated w i t h i n and between t e s t s of a t t e n t i o n . " I f we t h i n k of a f i l t e r i n g task as comparable to the person d i r e c t i n g a s p o t l i g h t a t the outside world, d i f f e r e n t people might d i f f e r i n the s i z e of the spot, the speed with which the spot c o u l d be moved, the c o n t r a s t between the amount of l i g h t c a s t on o b j e c t s i n s i d e rather than o u t s i d e of the spot, the extent to which the motion of the spot i s c o n t r o l l e d from i n t e r n a l r a t h e r than e x t e r n a l i n f o r m a t i o n , and a v a r i e t y of other f a c t o r s . In a search task, there c o u l d be d i f f e r e n c e s i n the e f f e c t of P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 12 i n c r e a s i n g the s p a t i a l area of s e a r c h , of the number of d i s t r a c t o r s belonging to an i r r e l e v a n t category, of whether the t a r g e t c a t e g o r y i s a w e l l - e s t a b l i s h e d and f a m i l i a r one, and so on. I t i s not obvious a p r i o r i whether these measures are a l l r e l a t e d to a s i n g l e dimension of 'goodness of a t t e n t i o n ' , or whether they a l l v a r y independently." (p.287) T h i s quote along with Broadbent et a l ' s r e s u l t s might lead one to conclude t h a t he b e l i e v e s that d i s t r a c t i b i l i t y does not g e n e r a l i z e a c r o s s tasks or t h a t h i s measures of d i s t r a c t i b i l i t y may have been a s s e s s i n g d i f f e r e n t a b i l i t i e s . However two important f a c t o r s have been overlooked which might account f o r Broadbent e t a l ' s task s p e c i f i c f i n d i n g s : sample s i z e , which w i l l a f f e c t the s e n s i t i v i t y and s t a t i s t i c a l power of the r e s u l t s , and v a l i d i t y . Broadbent et a l n e g l e c t e d to s a t i s f y the standard i n d i v i d u a l d i f f e r e n c e r e s e a r c h requirement of a l a r g e sample s i z e . His average sample s i z e of twenty for each experimental task h a r d l y seems capable of d e t e c t i n g i n d i v i d u a l d i f f e r e n c e s i n d i s t r a c t i b i l i t y . The s m a l l sample s i z e s might account f o r the absence of c o r r e l a t e d performance r e s u l t s on the two main types of d i s t r a c t i o n t a s k s : f i l t e r and s e a r c h . In order to r e s o l v e t h i s p o t e n t i a l problem of inadequate power, one major goal of t h i s f i r s t s e c t i o n of the t h e s i s i s to assess d i s t r a c t i b i l i t y by a paper and p e n c i l performance t e s t which can be a d m i n i s t e r e d to a l a r g e group of i n d i v i d u a l s . I t i s hoped t h a t such a procedure w i l l provide an adequate t e s t of P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s In D i s t r a c t i b i l i t y 13 i n d i v i d u a l d i f f e r e n c e s a t l e a s t i n terms of s t a t i s t i c a l power (Glass & Hopkins, 1984). The q u e s t i o n of v a l i d i t y a r i s e s when we consider the u s u a l l y accepted o p e r a t i o n a l d e f i n i t i o n of d i s t r a c t i b i l i t y . As was noted i n Chapter 1, d i s t r a c t i b i l i t y i s g e n e r a l l y d e f i n e d as the i n a b i l i t y to s e l e c t r e l e v a n t s t i m u l i . Evidence f o r d i s t r a c t i b i l i t y i s found i n the d e t e r i o r a t i o n of task performance i n i n d i v i d u a l s who are h i g h l y d i s t r a c t i b l e when confronted with a task c o n t a i n i n g d i s t r a c t o r s , while the performance of n o n - d i s t r a c t i b l e i n d i v i d u a l s i s expected to be r e l a t i v e l y u n a f f e c t e d by the presence of d i s t r a c t o r s . Hence, d i s t r a c t i b i l i t y i s c h a r a c t e r i z e d by i n d i v i d u a l i n a b i l i t y to ignore I r r e l e v a n t s t i m u l i . T h i s d e f i n i t i o n suggests that when s e l e c t i n g a p p r o p r i a t e d i s t r a c t o r s , i t i s p r e f e r a b l e f o r the d i s t r a c t o r s to be c l e a r l y d i s t i n c t from the task . R e c a l l , we are i n t e r e s t e d i n d i s t r a c t i o n , not disembedding a b i l i t y , such as tha t u s u a l l y found i n d i s c u s s i o n s of f i e l d dependence (Witkin & Berry, 1975; W i t k i n , 1962). The more s i m i l a r the task and d i s t r a t o r a r e , the g r e a t e r the o p p o r t u n i t y f o r measuring disembedding a b i l i t y or c o n f u s i o n r a t h e r than d i s t r a c t i o n . Evidence f o r t a s k - d i s t r a c t o r c o n f u s a b i 1 i t y being dependent on p h y s i c a l s i m i l a r i t y i s present i n S c h i f f r i n ' s (1988) summary of these f i n d i n g s : "By now hundreds of s t u d i e s t e s t i f y to the p o s i t i v e r e l a t i o n s h i p between speed of se a r c h and the s i m i l a r i t y d i f f e r e n c e between t a r g e t s and d i s t r a c t o r s and t h i s r e l a t i o n s h i p transcends c o n s i d e r a t i o n s of type of t r a i n i n g and other f a c t o r s " P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 14 (p.749). Q u i n l a n and Humphreys ( i n press) and Duncan (1985, i n press) found t h a t search i s speeded by d i s s i m i l a r i t y of t a r g e t s to d i s t r a c t o r s as w e l l as by s i m i l a r i t y of d i s t r a c t o r s to each other ( c i t e d i n S c h i f f r i n , 1988). Confounding c o u l d e x p l a i n Broadbent et a l ' s complex p a t t e r n of f i n d i n g s . Thus h i s use of d i g i t s and l e t t e r s as d i s t r a c t o r s i n f i l t e r and search tasks where the t a r g e t s are l e t t e r s may r e q u i r e d i f f e r e n t higher l e v e l c a t e g o r i z a t i o n or i d e n t i f i c a t i o n processes to be evoked, i n v o l v i n g d i f f e r e n t c o g n i t i v e operations for d i f f e r e n t i d e n t i f i c a t i o n parameters. In f a c t , the more s i m i l a r the d i s t r a c t o r s were to the t a r g e t i n Broadbent et a l ' s study, the more haphazard the r e s u l t s appeared. The r e f o r e , an important c o n s i d e r a t i o n i n s e l e c t i n g a d i s t r a c t i o n task i s to use d i s t r a c t o r s which are c l e a r l y d i s t i n c t from the t a r g e t s . T h i s w i l l permit us to o b t a i n a l e s s confounded measure of d i s t r a c t i b i l i t y . Support f o r the e x i s t e n c e of a g e n e r a l i z e d conception of d i s t r a c t i b i l i t y as mentioned e a r l i e r , e x i s t s i n r e s e a r c h on i n t e l l i g e n c e and c h i l d h o o d l e a r n i n g d i s a b i l i t i e s . Sternberg (1979) argues t h a t a major c o n t r i b u t o r to i n t e l l e c t u a l f u n c t i o n i s a t t e n t i o n . He presumes t h a t the w e l l e s t a b l i s h e d d i f f e r e n c e s i n i n t e l l i g e n c e a c r o s s i n d i v i d u a l s i s p a r a l l e l e d by d i f f e r e n c e s i n a t t e n t i o n a b i l i t i e s such as d i s t r a c t i b i l i t y . Experimental support fo r t h i s , although l i m i t e d , i s found i n r e s e a r c h using dual task experiments (Hunt, 1980) and d i c h o t i c l i s t e n i n g experiments (Keele, N e i l l & De Lemos, 1978). P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 15 S i m i l a r l y , c l i n i c a l r e s e a r c h on h y p e r a c t i v i t y , A t t e n t i o n D e f i c i t D i s o r d e r s and L e a r n i n g D i s a b i l i t i e s f r e q u e n t l y t e s t f o r the e x i s t e n c e of some g e n e r a l i z e d a t t e n t i o n a l i n a b i l i t y , to e x p l a i n the causes of these impairments. In g e n e r a l i t appears that the A t t e n t i o n a l D e f i c i t Disorder or h y p e r a c t i v i t y i n c h i l d r e n i s r e l a t e d to an i n a b i l i t y to s u s t a i n a t t e n t i o n over time. (Douglas & P e t e r s , 1979; Douglas, 1983). This i n a b i l i t y to s u s t a i n a t t e n t i o n a l s o appears to g e n e r a l i z e across the v i s u a l and a u d i t o r y m o d a l i t i e s (Sykes, 1973). Learning d i s a b l e d c h i l d r e n on the other hand, appear t o be d i s t r a c t i b l e i n a s i m i l a r manner to t h a t d e s c r i b e d and used i n t h i s t h e s i s (Douglass & P e t e r s , 1979; Douglas, 1983). Regardless of the p r e c i s e form of a t t e n t i o n , these s t u d i e s demonstrate that i t i s reasonable to view d i s t r a c t i b i l i t y i n a manner which g e n e r a l i z e s a c r o s s s i t u a t i o n s and ta s k s as w e l l as d i s p l a y s c o n s i s t e n t d i f f e r e n c e s between i n d i v i d u a l s . The Makings of a D i s t r a c t o r The aim of t h i s s e c t i o n i s to s p e c i f y the d i s t r a c t i o n task used i n t h i s study and to e x p l a i n the r a t i o n a l e for i t s s e l e c t i o n . Since the task design d i c t a t e s what i s being assessed, choosing an a p p r o p r i a t e t e s t i s c r i t i c a l . We have a l r e a d y seen t h a t some of the problems t h a t were present i n Broadbent e t a l ' s paradigm may have weakened i t s u s e f u l n e s s as a t o o l f o r measuring i n d i v i d u a l d i f f e r e n c e s i n d i s t r a c t i b i l i t y . Thus i t i s important to make sure t h a t we u t i l i z e a simple enough task, with c l e a r l y i r r e l e v a n t d i s t r a c t o r s , to assure t h a t P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 16 we are measuring o n l y d i s t r a c t i b i l i t y and not dlsembedding, c o n f u s i o n or higher l e v e l c o g n i t i v e s o r t i n g a b i l i t y . The r e l e v a n t dimension to c o n s i d e r i s whether the d i s t r a c t o r s are c l e a r l y i d e n t i f i a b l e , hence e x t r i n s i c to the t a r g e t (as i n F i g u r e 1A) or whether the t a r g e t must f i r s t be i s o l a t e d and disembedded as when the t a r g e t and d i s t r a c t o r s are i n t r i n s i c a l l y r e l a t e d (as i n Fig u r e I B ) . Given our d i s c u s s i o n above, i t should be c l e a r t h a t e x t r i n s i c d i s t r a c t o r s are p r e f e r a b l e , as i n F i g u r e 1A where the t a r g e t i s o l a t i o n task i n v o l v e s simple i d e n t i f i c a t i o n . T h i s c o n t r a s t s with s t u d i e s t h a t use i n t r i n s i c d i s t r a c t o r s and i n t e g r a t e the r e l e v a n t with the i r r e l e v a n t s t i m u l u s dimensions (Stroop, 1935; Witkin & Berry, 1975; Egeth, V i r g i & Garbart, 1984, Treisman, 1982, 1986; Broadbent e t a l . , 1986 ). Thus we w i l l a v o i d the so c a l l e d "task i n t r i n s i c " d i s t r a c t o r s and concentrate on those that have been c a l l e d "task e x t r i n s i c " d i s t r a c t o r s (Davies, Jones & T a y l o r , 1984). I n s e r t F i g u r e 1 By u s i n g an e x t r i n s i c type of d i s t r a c t o r , we r e s o l v e the problem of i n a d v e r t e n t l y measuring f i e l d dependency, co n f u s i o n , s o r t i n g a b i l i t y or other c o g n i t i v e s k i l l dimensions. At the same time we run the r i s k of using i n e f f e c t i v e d i s t r a c t o r s . In order to a v o i d t h i s secondary problem, we d e l i b e r a t e l y s e l e c t e d d i s t r a c t o r s which are d i f f i c u l t to i g n o r e . What makes d i s t r a c t o r s n o t i c e a b l e can be found i n the models of a t t e n t i o n mentioned i n Chapter 1. Messages i n the r e j e c t e d channels are Figure 1R Task Extrinsic Distractors Target 0 Locate the target in the following array : Fiqure IB Task Intrinsic Distractors Target: Locate the target in the following array: ft / / / / / / / / Figure (la) R distractor in which the ta r is distinct from the distractor items. Figure (lb) Rn embedded figures test in which the target is found in the more complex array. The complex array acts as an inteqrated distractor and task. (From Coren, Porac and Ward, 1984) P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 17 f i l t e r e d out a t an e a r l y stage i n the p e r c e p t u a l process, which suggests t h a t the i n i t i a l s e l e c t i o n i s based on p h y s i c a l and low l e v e l c h a r a c t e r i s t i c s . One p h y s i c a l c h a r a c t e r i s t i c i s sudden onset, while a low l e v e l f a c t o r i s n o v e l t y or expectancy. Because these s t i m u l u s c h a r a c t e r i s t i c s can t r i g g e r channel s w i t c h i n g i n d i v i d e d a t t e n t i o n tasks (Broadbent, 1955), presumably they would a l s o be c h a r a c t e r i s t i c s of e f f e c t i v e d i s t r a c t o r s . In h i s work on a t t e n t i o n , Kahneman (1973) p o s t u l a t e d the n o t i o n of "enduring d i s p o s i t i o n s " which are tendencies that we have to process loud n o i s e s , sudden motions, b r i g h t c o l o r s and other unusual events. These enduring d i s p o s i t i o n s provide suggestions about what would be optimal d i s t r a c t o r s (e.g. loud n o i s e ) . D.O. Hebb (1955) s i m i l a r l y argues t h a t the p r o b a b i l i t y of s p e c i f i c i n f o r m a t i o n being s e l e c t e d i s i n c r e a s e d by c e r t a i n p r o p e r t i e s of t h i s i n f o r m a t i o n along with the s t a t e of the i n d i v i d u a l . P r o p e r t i e s of e x t e r n a l events t h a t increase the p r o b a b i l i t y of i n f o r m a t i o n being s e l e c t e d i n c l u d e : p h y s i c a l i n t e n s i t y ; time i n t e r v a l between s t i m u l a t i o n ; high frequency as opposed to low frequency sound and sounds as opposed to v i s u a l s t i m u l i . Hence, both Kahneman and Hebb d i s c u s s e x t e r n a l s t i m u l i t h a t are most l i k e l y to capture our a t t e n t i o n . I t . i s important to recognize t h a t these d i f f e r e n t t h e o r i s t s (even with t h e i r d i f f e r e n t t h e o r e t i c a l o r i e n t a t i o n s ) do agree on the p r o p e r t i e s of a s a l i e n t s t i m u l u s (eg. unexpected, n o v e l , i n t e n s e ) . T h i s f i r s t subexperiment t e s t s whether d i s t r a c t i b i l i t y can P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 18 be assessed b e h a v i o r a l l y v i a a paper and p e n c i l d i s t r a c t i o n t e s t . We must demonstrate that we have a task i n which some i n d i v i d u a l s are d i s t r a c t e d to a l a r g e degree, while others are not d i s t r a c t e d or a f f e c t e d to a much l e s s e r e x t e n t . Once a task has been d e r i v e d i n which there i s a s u f f i c i e n t degree of i n d i v i d u a l v a r i a b i l i t y we can then seek c o r r e l a t e s and p r e d i c t o r s which can separate d i s t r a c t i b l e from n o n - d i s t r a c t i b l e i n d i v i d u a l s which may, l a t e r , shed l i g h t on the v a l i d i t y of va r i o u s models of a t t e n t i o n i n e x p l a i n i n g d i s t r a c t i b i l i t y . Method The D i s t r a c t i o n Test The d i s t r a c t i o n t e s t (Appendix A) a s s e s s e s performance under c o n d i t i o n s of a u d i t o r y and v i s u a l d i s t r a c t o r s t i m u l a t i o n . S p e c i f i c a l l y , the t e s t i s a speeded v i s u a l search task t h a t c o n t a i n s d i s t r a c t o r s placed u n p r e d i c t a b l y around the t a r g e t items of the search t a s k . The s u b j e c t ' s task i s to scan across a set of l e t t e r s and/or numbers which are i n groups of three on the l e f t s i d e of the page, f i n d the t a r g e t item which i s un d e r l i n e d and c r o s s out t h i s same s e t of items i n the response s e t which i s l o c a t e d on the r i g h t s i d e of the page. Fi g u r e 2 co n t a i n s a sample of these items. I n s e r t F i g u r e 2 The b a s i c search task i s a v a r i a t i o n of a t e s t t h a t appears Figure 2 auu UuA auu AUU aau UuA D8R R80 R8D D8R 8DR RD8 POC PCO POC OCP PCC OPC PBD PDB DPB BPD PBD DBP SYX SXY XYS SXY SYX XYX PVC PCV VCP CPV PVC VPC Figure (2) Sample items from the distraction t e s t without distractors present. P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 19 i n the D i f f e r e n t i a l A p t i t ude Test (Bennett, Seashore & Wesman, 1982). The o r i g i n a l a p t i t u d e t e s t was designed to measure c l e r i c a l s k i l l s . The v e r s i o n used here i s s l i g h t l y more d i f f i c u l t because i t c o n t a i n s t h r e e , r a t h e r than the two l e t t e r t a r g e t s t h a t were found i n the o r i g i n a l . The d i s t r a c t i o n t e s t was designed to r e q u i r e c o n c e n t r a t i o n but o n l y minimal c o g n i t i v e engagement. T h i s simple search task measured i n d i v i d u a l s ' a b i l i t y to s e l e c t r e l e v a n t s t i m u l i and not t h e i r competency f o r prolonged memory, mathematical, v e r b a l or some other higher order s k i l l . I r r e l e v a n t s t i m u l i were presented i n e i t h e r the v i s u a l or a u d i t o r y modality. Each s u b j e c t had one s e c t i o n without d i s t r a c t o r s , one with v i s u a l and one with a u d i t o r y d i s t r a c t o r s which w i l l be r e f e r r e d to r e s p e c t i v e l y as the C o n t r o l , V i s u a l and A u d i t o r y D i s t r a c t i o n s e c t i o n s . Each s e c t i o n of the task was timed and had a d u r a t i o n of three minutes. In the v i s u a l d i s t r a c t i o n s e c t i o n the v i s u a l d i s t r a c t o r s were meaningful p i c t u r e s placed u n p r e d i c t a b l y around the t a r g e t items. Figure 3 c o n t a i n s a sample of these items. These d i s t r a c t o r s and the search task comprise an e x t r i n s i c type of t e s t . Examples of the v i s u a l d i s t r a c t o r s i n c l u d e p i c t u r e s of a s k e l e t o n , a s k i e r , a dog and a boat. In the a u d i t o r y d i s t r a c t i o n s e c t i o n , while s u b j e c t s were performing the v i s u a l s e arch task eighteen meaningful a u d i t o r y d i s t r a c t o r s , ranging from 75 to 95 d e c i b e l s , were presented at v a r i a b l e , unexpected i n t e r v a l s . Interspersed p e r i o d s of s i l e n c e averaged three seconds. Examples of these P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 20 d i s t r a c t o r s i n c l u d e sounds of a screaming s i r e n , a c r y i n g baby, a dog barking and audience n o i s e . I n s e r t Figure 3 As was noted above there was a l s o a c o n t r o l c o n d i t i o n i n which no d i s t r a c t o r s were present. The comparison of performance on the no d i s t r a c t o r s e c t i o n compared with performance on the d i s t r a c t o r s e c t i o n s provided a measure of the e f f e c t s of the d i s t r a c t o r s . In a d d i t i o n to the experimental group d e s c r i b e d above, there was a c o n t r o l group. The c o n t r o l group r e c e i v e d the same three s e c t i o n s of the search t e s t with no d i s t r a c t o r s . I t was inc l u d e d to t e s t f o r any order, f a t i g u e , or p r a c t i c e e f f e c t s . N o t ice t h a t the task i s a search task and the i r r e l e v a n t l e t t e r s and numbers are not considered to be d i s t r a c t o r s . D i s t r a c t o r s , i n the context of t h i s study, r e f e r o n l y to the p i c t o r i a l and a u d i t o r y s t i m u l i i r r e l e v a n t t o the domain of s t i m u l i being a c t i v e l y c a t e g o r i z e d . Subjects Three hundred and e i g h t undergraduate s u b j e c t s at the U n i v e r s i t y of B r i t i s h Columbia served as s u b j e c t s . Of these, 272 s u b j e c t s p a r t i c i p a t e d i n two experimental groups. The f i r s t group c o n s i s t e d of 199 s u b j e c t s who r e c e i v e d the d i s t r a c t i o n t e s t which appears i n Appendix A. A second experimental group c o n s i s t i n g of 73 s u b j e c t s who r e c e i v e d the same t e s t but with the v i s u a l and a u d i t o r y d i s t r a c t i o n s e c t i o n s of the t e s t r e v e r s e d . 20a CTi . - s i i r - . . — . O nvx nxv _3S„xnv vxn xvn bid dlb ldb lbd bdl aru aur ura rau rua i vwu wvu uvw vwv vuw .... uwm wum wmu 0wu umw 679 769 967 697 976 nvx xvn vxn nxv xnv dlbl Ldb bid bdl lbd ura aru^^Sr aur rua rau vuw wvu uwv vwu uvw wmu umw vum^j^mwu uwm 697 967 769 679 976 Figure (3) Sample items from the distraction t e s t with distractors present. P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 21 The s i z e of these groups should be l a r g e enough to a l l o w f o r meaningful c o r r e l a t i o n a l a n a l y s i s of i n d i v i d u a l d i f f e r e n c e s , and should have adequate power. A s m a l l e r c o n t r o l c o n d i t i o n of 36 s u b j e c t s was i n c l u d e d to t e s t f o r f a t i g u e or p r a c t i c e e f f e c t s . T h i s group, r e c e i v e d no d i s t r a c t o r s , but merely three s u c c e s s i v e p r e s e n t a t i o n s of the search task. T h i s s m a l l e r group s i z e i s p e r m i s s i b l e here because no i n d i v i d u a l d i f f e r e n c e a n a l y s i s i s to be performed on t h i s group. Only the group performance, w i l l be assessed i n t h i s c o n d i t i o n . R e s u l t s & D i s c u s s i o n Group Performance The b a s i c q u e s t i o n to be answered here, i s whether the d i s t r a c t i o n task p r o v i d e s us with a range of s c o r e s , c o n t a i n i n g a number of i n d i v i d u a l s who are d i s t r a c t e d (show performance d e t e r i o r a t i o n r e l a t i v e to t h e i r performance with no d i s t r a c t o r s t i m u l i ) as w e l l as a number of i n d i v i d u a l s who are r e l a t i v e l y not d i s t r a c t e d . The wide d i s t r i b u t i o n of the number c o r r e c t s c o r e s i n Table 1 i l l u s t r a t e s the e x i s t e n c e of s u f f i c i e n t i n d i v i d u a l v a r i a b i l i t y i n performance on the d i s t r a c t i o n task to make i n d i v i d u a l d i f f e r e n c e a n a l y s i s meaningful. The wider range of scores i n the d i s t r a c t o r c o n d i t i o n s i s c o n s i s t e n t with the idea t h a t the d i s t r a c t o r s are having an e f f e c t upon some I n d i v i d u a l s but not o t h e r s , hence spreading the s c o r e s out. P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 22 I n s e r t Table 1 In order to assess the impact of d i s t r a c t o r s on performance we w i l l focus on changes i n speed and accuracy. A s i g n i f i c a n t decrease i n a c c u r a c y occurred when s u b j e c t s were exposed to d i s t r a c t o r s . T h i s was d e p i c t e d i n a s i g n i f i c a n t i n c rease i n the mean number of e r r o r s from a mean of .78 i n the c o n t r o l c o n d i t i o n to 1.34 i n the V i s u a l D i s t r a c t o r c o n d i t i o n (t=-5.69 p<.001) and 1.21 i n the A u d i t o r y D i s t r a c t o r c o n d i t i o n (t=-4.83 p<.001). T h i s i n c r e a s e i n the number of e r r o r s i n the two d i s t r a c t o r c o n d i t i o n suggests that the task i s a u s e f u l measure of d i s t r a c t i b i l i t y . Because of t h e i r s m a l l values and p o t e n t i a l f o r u n r e l i a b i l i t y , these e r r o r scores were not used i n d e r i v i n g s cores of d i s t r a c t i b i l i t y . Instead, the o p e r a t i o n a l d e f i n i t i o n of d i s t r a c t i o n , namely i n terms of performance decrement, are used. The number c o r r e c t scores from Table 1 were used to compute combined change scores which are used f o r the remainder of the study as the measures of d i s t r a c t i b i l i t y . S p e c i f i c a l l y , the number c o r r e c t i n the no d i s t r a c t o r c o n d i t i o n minus the number c o r r e c t i n the d i s t r a c t o r c o n d i t i o n s of the search task computed s e p a r a t e l y f o r the V i s u a l and A u d i t o r y D i s t r a c t i o n t a s k s , were used as measures of the. e f f e c t of the d i s t r a c t o r on performance, and hence d i s t r a c t i b i l i t y . Note t h a t t h i s computation produces a p o s i t i v e value i f there i s a performance  decrement; hence high scores on these measures represent high d i s t r a c t i b i l i t y . Table 1 c o n t a i n s the measures of v i s u a l and a u d i t o r y d i s t r a c t i b i l i t y s c o r e s . As we had hoped i n d e s i g n i n g 22a Table 1 Group Performance on D i s t r a c t i o n Task (n=272) minimum bottom md top maximum range score l / 4 i l e 1/2 l / 4 i l e score max-min D i s t r a c t o r : None (C o n t r o l ) # C o r r e c t 44 56 61 67 82 38 V i s u a l # C o r r e c t 34 50 57 63 86 52 A u d i t o r y # C o r r e c t 35 55 62 69 92 57 V i s u a l D i s t r a c t -i b i l i t y -10 1 5 7 16 26 A u d i t o r y D i s t r a c t -i b i l i t y -18 -5 -1 2 14 32 V i s u a l D i s t r a c t i b i l i t y = C o n t r o l # C o r r e c t - V i s u a l # C o r r e c t A u d i t o r y D i s t r a c t i b i l i t y = C o n t r o l # C o r r e c t - A u d i t o r y # C o r r e c t P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 23 t h i s t ask, there i s a l a r g e range of d i s t r a c t i b i l i t y shown, with many i n d i v i d u a l s showing marked d i s t r a c t i o n , i n terms of performance decrement, while others appear to be r e l a t i v e l y u n a f f e c t e d . The d i s t r i b u t i o n s are f a i r l y normal, hence no s p e c i a l s t a t i s t i c a l c o r r e c t i o n should be r e q u i r e d i n f u r t h e r a n a l y s i s . E a r l i e r we mentioned the q u e s t i o n of d i s t r a c t i b i l i t y as a g e n e r a l i z e d a b i l i t y or i n a b i l i t y . Based on a h i g h l y s i g n i f i c a n t p o s i t i v e c o r r e l a t i o n between a u d i t o r y and v i s u a l d i s t r a c t i b i l i t y (r=.48 p<.001) we can conclude that d i s t r a c t i b i l i t y does seem to have a reasonable g e n e r a l i z a b i l i t y a c r o s s m o d a l i t i e s and/or r e s o u r c e s . I n d i v i d u a l s who tend to be d i s t r a c t e d by v i s u a l d i s t r a c t o r s a l s o are d i s t r a c t e d by a u d i t o r y d i s t r a c t o r s , a t l e a s t f o r the present t a s k . F a t i g u e . P r a c t i c e and Order E f f e c t In order to demonstrate t h a t d i s t r a c t i o n i s the u n d e r l y i n g cause of the p a t t e r n of behavior noted i n Table 1 we need to e l i m i n a t e the p o t e n t i a l confounds of f a t i g u e and p r a c t i c e . These e f f e c t s can be d i s m i s s e d with r e s p e c t to the present f i n d i n g s , when we look a t the r e s u l t s of the c o n t r o l (no d i s t r a c t o r ) experimental group. The mean number c o r r e c t f o r the three s e c t i o n s of the d i s t r a c t i o n t e s t was 60.1, 61.7 and 61.8 r e s p e c t i v e l y . The corresponding number of e r r o r s f o r the three s e c t i o n s were .97, 1.39 and 1.53. N o n - s i g n i f i c a n t d i f f e r e n c e s i n the number c o r r e c t occurred between a l l s e c t i o n s of the d i s t r a c t i o n task (F(2,35) = 2.16 n . s ) . There a l s o were P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 24 n o n - s i g n i f i c a n t d i f f e r e n c e s between the number of e r r o r s on a l l s e c t i o n s of the d i s t r a c t i o n task (F(2,35) = 1.79 n . s . ) . The n o n - s i g n i f i c a n t d i f f e r e n c e s on both the number c o r r e c t and the number of e r r o r s a c r o s s the three s e c t i o n s of the c o n t r o l group's t e s t , e l i m i n a t e s the p o s s i b i l i t y of a f a t i g u e or p r a c t i c e e f f e c t which i s understandable g i v e n the f a c t t h a t there were only three s e c t i o n s administered and each was onl y three minutes i n d u r a t i o n . R e c a l l t h a t the experimental groups were t e s t e d under both v i s u a l and a u d i t o r y d i s t r a c t i o n c o n d i t i o n s , but one group with the v i s u a l and the other with the a u d i t o r y d i s t r a c t i o n task f i r s t . In order to c o n t r o l f o r any p o t e n t i a l order e f f e c t s between the two t e s t o r d e r s , the measures of d i s t r a c t i b i l i t y f o r the remainder of the t h e s i s have been s t a n d a r d i z e d w i t h i n each t e s t order. T h i s p r e s e r v e s the r e l a t i v e rank order of each i n d i v i d u a l i n terms of d i s t r a c t i b i l i t y while i t e l i m i n a t e s any group mean d i f f e r e n c e s . The n o n s i g n i f i c a n t d i f f e r e n c e i n v a r i a n c e for the two experimental orders on the V i s u a l D i s t r a c t i o n task (S.D. of V i s u a l / A u d i t o r y group = 4.4 and S.D. of A u d i t o r y / V i s u a l group = 5.2) and the A u d i t o r y D i s t r a c t i o n task (S.D. of V i s u a l / A u d i t o r y group = 5.4 and S.D. of A u d i t o r y / V i s u a l group = 5.2) supports the v a l i d i t y of t h i s procedure, a l l o w i n g us to combine the two groups, e l i m i n a t i n g mean d i f f e r e n c e s which are not the focus of t h i s t h e s i s , and p r e s e r v i n g i n d i v i d u a l d i f f e r e n c e s . Since the concern of t h i s study i s with the i n d i v i d u a l d i f f e r e n c e s i n d i s t r a c t i b i l i t y , P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 25 on l y the r e l a t i v e s c o r e s are important and these are captured i n the s t a n d a r d i z e d d i s t r a c t i b i l i t y s c o r e s . In summary, both the v i s u a l and a u d i t o r y d i s t r a c t i o n c o n d i t i o n s compared to the c o n t r o l c o n d i t i o n were found to produce an e f f e c t i v e d i s t r i b u t i o n of d i s t r a c t i o n s c o r e s . T h i s was demonstrated by the e x i s t e n c e of l a r g e v a r i a b i l i t y among i n d i v i d u a l s ' s cores i n terms of t h e i r performance under d i s t r a c t i o n c o n d i t i o n s as compared t o c o n d i t i o n s of no d i s t r a c t i o n . A l s o the s i g n i f i c a n t and p o s i t i v e c o r r e l a t i o n between the two d i s t r a c t i b i l i t y s c ores demonstrates t h a t d i s t r a c t i b i l i t y g e n e r a l i z e s , a t l e a s t a c r o s s m o d a l i t i e s . The above a n a l y s i s of the d i s t r a c t i o n task suggests t h a t i t may be u s e f u l as a c r i t e r i o n measure to assess d i s t r a c t i b i l i t y as an i n d i v i d u a l c h a r a c t e r i s t i c . Let us now t u r n t o the q u e s t i o n of whether we can pred i c t an i n d i v i d u a l ' s performance under c o n d i t i o n s of d i s t r a c t i o n . T h i s q u e s t i o n forms the focus f o r the f o l l o w i n g c h a p t e r s . P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 26 Chapter 3 S u b j e c t i v e Report of D i s t r a c t i b i l i t y : A P r e d i c t o r of D i s t r a c t i b i l i t y ? Since the goal of t h i s t h e s i s i s t o p r e d i c t i n d i v i d u a l d i f f e r e n c e s i n d i s t r a c t i b i l i t y , the most s t r a i g h t f o r w a r d and f a c e - v a l i d method of a c c o m p l i s h i n g t h i s i s t o simply ask i n d i v i d u a l s v i a a s e t of face v a l i d performance based questions whether they are d i s t r a c t i b l e . Presumably, a person would be expected to know i f t h e i r performance h a b i t u a l l y d e t e r i o r a t e s under c o n d i t i o n s where d i s t r a c t i n g s t i m u l i are present. The use of performance based q u e s t i o n s i s important s i n c e i n d i v i d u a l s are o f t e n i n a c c u r a t e a t a s s e s s i n g t h e i r own competence based upon g l o b a l q u e s t i o n s . For i n s t a n c e , when asked i f one's v i s i o n i s normal, one gets v e r y poor d i s c r i m i n a b i l i t y or accuracy (e.g. Coren & Porac, 1975) while through the use of s p e c i f i c and a p p r o p r i a t e l y s e l e c t e d performance q u e s t i o n s , high degrees of accuracy can be obtained on a number of sensory dimensions (e.g. Coren & Hak s t i a n , 1987; 1988). For the purposes of a s s e s s i n g d i s t r a c t i b i l i t y , examples of such performance based q u e s t i o n s might i n c l u d e "Do uneven shadows on the page of a book make i t d i f f i c u l t to read?" or "Are you e a s i l y d i s t r a c t e d by c o n v e r s a t i o n s going on around you?" Such a performance based s u b j e c t i v e measure of d i s t r a c t i b i l i t y i s used i n t h i s P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 27 subexperiment and i t i s e n t i t l e d the "Stimulus S e l e c t i v i t y Inventory" (See Appendix B). The d i s t r a c t i o n task was p r e d i c t e d to be a b e h a v i o r a l v a l i d a t i o n of t h i s i n v e n t o r y i f s u b j e c t s can a c c u r a t e l y r e p o r t t h e i r own d i s t r a c t i b i l i t y . Encouragement f o r use of a s e l f - r e p o r t of d i s t r a c t i b i l i t y can be found i n Broadbent, Cooper, F i t z g e r a l d and Parkos' r e s e a r c h using the " C o g n i t i v e F a i l u r e Q u e s t i o n n a i r e " (CFQ) (1982). The CFQ i s a q u e s t i o n n a i r e measure of s e l f - r e p o r t e d f a i l u r e s i n p e r c e p t i o n , memory and motor f u n c t i o n . I t i n q u i r e s about the frequency of 25 everyday performance impairments, such as f o r g e t t i n g where a book i s , f a i l i n g to see a road s i g n , or dropping something. Some argue t h a t the CFQ i s a measure of everyday f a i l u r e s of s e l e c t i v e a t t e n t i o n (Tipper & B a y l i s , 1987). A l t e r n a t i v e l y , of course the CFQ might be more of a g e n e r a l s e l f - a s s e s s m e n t of c o g n i t i v e c o n f u s i o n . Broadbent et a l d i d note t h a t a f a i l u r e of c o n c e n t r a t i o n i s b e l i e v e d to be one of the u n d e r l y i n g components of what the i n v e n t o r y i s measuring (1982). Scores on the CFQ have been found to p r e d i c t some aspe c t s of performance on the search task used by Broadbent et a l . (1986) d e s c r i b e d i n Chapter 1 as w e l l as i n d i v i d e d a t t e n t i o n tasks ( H a r r i s & W i l k i n s , 1982; M a r t i n & Jones, 1984), s u g g e s t i n g t h a t the CFQ i s a v a l i d measure of some aspect of a t t e n t i o n a l focus, or r e l a t e d c o g n i t i v e p r o c e s s e s . These f i n d i n g s f o r the CFQ provided some optimism t h a t the Stimulus S e l e c t i v i t y Inventory t h a t we were d e v e l o p i n g , might be an e f f e c t i v e p r e d i c t o r of d i s t r a c t i b i l i t y . Some c a u t i o n i s needed P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 28 s i n c e the e x t e r n a l v a l i d i t y of the CFQ t h a t H a r r i s (1982) and Broadbent et a l (1986) obtained were based on d i f f e r e n t a t t e n t i o n r e l a t e d t a s k s . D i v i d e d a t t e n t i o n and embedded d i s t r a c t o r / t a s k performance seem to be c h a r a c t e r i s t i c of an " i n t r i n s i c t a s k " t h a t might tap i n t o a t t e n t i o n a l a b i l i t i e s t h a t are independent of the present form of " e x t r i n s i c t ask" d i s t r a c t i b i l i t y . Poor performance on i n t r i n s i c tasks might be due to other f a c t o r s , such as c o n f u s i o n , f i e l d dependence, or d e f i c i t s i n disembedding a b i l i t y , s p a t i a l a b i l i t y or even higher l e v e l i d e n t i f i c a t i o n s k i l l s . Method  Subjects The 272 s u b j e c t s who completed the ( v i s u a l / a u d i t o r y ) d i s t r a c t i o n task i n the f i r s t subexperiment served as s u b j e c t s i n t h i s subexperiment. Stimulus S e l e c t i v i t y Inventory The Stimulus S e l e c t i v i t y Inventory i n c l u d e d here as Appendix B, c o n s i s t s of a s e r i e s of q u e s t i o n s which are f a c e - v a l i d measures of responsiveness to extraneous or i r r e l e v a n t v i s u a l and a u d i t o r y s t i m u l i . Most of the questions i n t h i s i n v e n t o r y are e i t h e r o r i g i n a l f a c e - v a l i d items, v a r i a n t s of Mehrabian's "Stimulus Screening Inventory" (1976) or N i d e f f e r ' s "Test of A t t e n t i o n a l and I n t e r p e r s o n a l S t y l e " P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 29 (1976). The Stimulus Screening Inventory items were c a t e g o r i z e d as e i t h e r a measure of V i s u a l , A u d i t o r y or General d i s t r a c t i b i l i t y . Each item was s t r u c t u r e d so t h a t the s u b j e c t c o u l d s e l e c t from f i v e s t i m u l u s a l t e r n a t i v e s which were "never, seldom, o c c a s i o n a l l y , f r e q u e n t l y and always". Samples of these items are "I f i n d i t d i f f i c u l t to c oncentrate while a fa u c e t i s d r i p p i n g . " ; "Uneven shadows on the page of a book make i t d i f f i c u l t to read." or "I f i n d i t d i f f i c u l t to study or l i s t e n to something with people t a l k i n g nearby." In a d d i t i o n to the 38 d i s t r a c t i o n s p e c i f i c items, 12 b e h a v i o r a l l y v a l i d a t e d s e l f - r e p o r t q u e s t i o n s of a r o u s a b i l i t y as a t r a i t from Coren's (1988) A r o u s a b i l i t y P r e d i s p o s i t i o n Scale were a l s o included i n the S t i m u l u s - S e l e c t i v i t y Inventory. The reason f o r i n c l u d i n g these items was due to t h e i r p o t e n t i a l as a p r e d i c t o r of d i s t r a c t i b i l i t y . A r o u s a l has been suggested as a f a c t o r i n a t t e n t i o n a l processes q u i t e f r e q u e n t l y , as we w i l l see more e x p l i c i t l y i n Chapter 4. As an example, Mehrabian and R u s s e l l (1973) and Mehrabian (1976) p o s t u l a t e a connection between an a r o u s a l seeking tendency and s t i m u l u s s c r e e n i n g • Stimulus s c r e e n i n g , the i n v e r s e of d i s t r a c t i b i l i t y , i s the automatic s c r e e n i n g of i r r e l e v a n t s t i m u l i and r a p i d h a b i t u a t i o n to d i s t r a c t i n g , i r r e l e v a n t s t i m u l i . Mehrabian and R u s s e l l p r e d i c t e d that a stimulus screener tends to a v o i d exposure to s t i m u l i t h a t Increase a r o u s a l and a non-screener tends to seek out such s t i m u l i . As we w i l l see l a t e r , both a r o u s a l and p e r s o n a l i t y t h e o r i e s suggest t h a t c e r t a i n inherent i n d i v i d u a l P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 30 c h a r a c t e r i s t i c s d i c t a t e p r e f e r e n c e s for exposure to c e r t a i n p a t t e r n s t i m u l a t i o n . Thus p r e d i s p o s i t i o n s such as s t i m u l u s seeking or stimulus avoidance c o u l d a l s o be u s e f u l p r e d i c t o r s of d i s t r a c t i b i l i t y . A r o u s a l seeking tendency has been shown to r e l a t e to such t h i n g s as environmental p r e f e r e n c e and p e r c e p t i o n (Mehrabian & West, 1977). For now we w i l l c o n s i d e r a r o u s a b i l i t y more along the l i n e s of a r o u s a l s t a t e as i s done i n Chapter 4. Coren's Arousal P r e d i s p o s i t i o n Scale (1988) l i k e Thayer's A r o u s a l Scale (1978), views a r o u s a l as a m u l t i d i m e n s i o n a l phenomenon or a s e t of subdimensions. T h i s o r i e n t a t i o n i s common to many others who have looked a t a r o u s a b i l i t y as a t r a i t (Borkovec, 1976, 1979; Davidson & Schwartz, 1976; S u e d f e l d , 1980). Coren's twelve item s c a l e i s based on s e l f - r e p o r t s of g e n e r a l c o g n i t i v e a r o u s a b i l i t y and was c r o s s - v a l i d a t e d and s u c c e s s f u l l y used to p r e d i c t insomnia. I t s i n c l u s i o n here seems a p p r o p r i a t e when we c o n s i d e r the t h e o r e t i c a l p o t e n t i a l f o r a r o u s a l as a f a c t o r i n d i s t r a c t i b i l i t y performance as w i l l be demonstrated i n the next chapter of t h i s t h e s i s . Apparatus and Procedure The d i s t r a c t i o n task d e s c r i b e d i n chapter 2 served as the c r i t e r i o n measure for d i s t r a c t i b i l i t y . The Stimulus S e l e c t i v i t y Inventory was administered to the experimental groups f i v e weeks p r i o r to a d m i n i s t r a t i o n of the d i s t r a c t i o n t e s t . The i n v e n t o r y was completed before the t e s t i n order to avoid the p o s s i b i l i t y P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 31 t h a t responses on the s e l f - r e p o r t i n v e n t o r y might be biased by memory of how s u b j e c t s performed on the d i s t r a c t i o n task i t s e l f . Persons f o r whom any data were mi s s i n g on any measure were omitted from the a n a l y s i s . R e s u l t s and D i s c u s s i o n O v e r a l l , there i s v i r t u a l l y no r e l a t i o n s h i p between s e l f - r e p o r t e d d i s t r a c t i b i l i t y (obtained by forming a r i t h m e t i c composites of e i t h e r the t o t a l s t i m u l u s s e l e c t i v i t y s c o r e , or su b s c a l e s based upon V i s u a l , A u d i t o r y or General d i s t r a c t i b i l i t y . ) and performance decrement i n the d i s t r a c t i o n t a s k . The absence of s i g n i f i c a n t c o r r e l a t i o n s between the items on the i n v e n t o r y and performance on the d i s t r a c t i o n t e s t i n d i c a t e t h at we are unable t o r e j e c t the n u l l hypothesis t h a t people cannot assess how d i s t r a c t i b l e they a r e . S p e c i f i c a l l y , there are no s i g n i f i c a n t r e l a t i o n s h i p s between the composite measures on the Stimulus S e l e c t i v i t y Inventory and e i t h e r V i s u a l D i s t r a c t i b i l i t y (r =.02 n.s.) or A u d i t o r y D i s t r a c t i b i l i t y (r=-.02 n . s . ) . In f a c t o n l y two of the i n d i v i d u a l items were s i g n i f i c a n t l y c o r r e l a t e d with the V i s u a l D i s t r a c t i b i l i t y measure ("Are you e a s i l y f r u s t r a t e d ? " r=.13 p<.05 and " I t i s easy f o r me to keep my mind on a s i n g l e s i g h t or sound." (reverse keyed) r= .20 p<.01). A l l 50 items were u n c o r r e l a t e d with the A u d i t o r y D i s t r a c t i b i l i t y measure. Table 2 shows the c o r r e l a t i o n s f o r the v a r i o u s subscales a g a i n s t the performance measures of d i s t r a c t i b i l i t y . N o t i c e , P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 32 from the t a b l e that none of the composites, i n c l u d i n g those which were based upon the a r o u s a b i l i t y items demonstrated any s i g n i f i c a n t p r e d i c t a b i l i t y . I n s e r t Table 2 To f u r t h e r explore these data, a f a c t o r a n a l y s i s was conducted. I t was u n s u c c e s s f u l i n s e p a r a t i n g the items i n t o d i f f e r e n t u n d e r l y i n g dimensions of d i s t r a c t i b i l i t y . The v i s u a l , a u d i t o r y and general d i s t r a c t i b i l i t y items d i d not show up as separate dimensions as was a n t i c i p a t e d . A l s o , a m u l t i p l e r e g r e s s i o n on these expected groups d i d not p r e d i c t performance on the d i s t r a c t i o n t e s t . The o n l y meaningful f a c t o r was an a r o u s a l dimension. Thus i t appears t h a t s u b j e c t s are not a b l e to a c c u r a t e l y r e p o r t whether they are d i s t r a c t i b l e or not. These n o n s i g n i f i c a n t f i n d i n g s might appear c o n t r a d i c t o r y to the f i n d i n g that Broadbent e t a l ' s C o g n i t i v e F a i l u r e Q u e s t i o n n a i r e (1982) was m e a n i n g f u l l y c o r r e l a t e d with performance on one of E r i k s e n ' s search tasks which i s of the i n t r i n s i c type. T h i s i n c o n s i s t e n c y can be a t t r i b u t e d to a t l e a s t two f a c t o r s . 1) "Task i n t r i n s i c " t e s t s r e q u i r e a separate a t t e n t i o n a l a b i l i t y from "task e x t r i n s i c " t e s t s as we have d i s c u s s e d e a r l i e r . 2) Only four of the 25 items i n the CFQ assess d i s t r a c t i b i l i t y while the r e s t assess general c o n f u s i o n . I t may then be t h a t the CFQ i s a s u b j e c t i v e measure of g e n e r a l i z e d c o n f u s i o n while the Stimulus S e l e c t i v i t y Inventory was designed as only a face v a l i d s u b j e c t i v e assessment of d i s t r a c t i b i l i t y . C l e a r l y such face v a l i d items do not Table 2 Stimulus S e l e c t i v i t y & D i s t r a c t i b i l i t y Pearson C o r r e l a t i o n s Stimulus S e l e c t i v i t y  Subscales V i s u a l S e l e c t i v i t y (n=262) A u d i t o r y S e l e c t i v i t y (n=265) A r o u s a b i l i t y (n=258) T o t a l S e l e c t i v i t y & A r o u s a b i l i t y (n=246) V i s u a l D i s t r a c t -i b i 1 i t y -.01 -.06 .04 02 Aud i t o r y D i s t r a c t -i b i l i t y -.05 05 -.03 02 A l l n o n - s i g n i f i c a n t P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 33 a c c u r a t e l y p r e d i c t the a c t u a l performance under c o n d i t i o n s of d i s t r a c t i o n . The f a i l u r e of the Stimulus S e l e c t i v i t y Inventory to p r e d i c t d i s t r a c t i b i l i t y c o u l d be e x p l a i n e d by N i s b e t t and Wilson's (1977) f i n d i n g t h a t people are unable to s u b j e c t i v e l y r a t e many pe r c e p t u a l and c o g n i t i v e a b i l i t i e s . The f o l l o w i n g statements i n d i c a t e the extent to which other i n v e s t i g a t o r s doubt people's a b i l i t y to observe the workings of t h e i r own minds. "The c o n s t r u c t i v e processes of encoding p e r c e p t u a l s e n s a t i o n s themselves never appear i n consciousness, t h e i r products do" ( N e i s s e r , 1967 p.301). S i m i l a r l y , Mandler (1975a) argues t h a t "the a n a l y s i s of s i t u a t i o n s and a p p r a i s a l of the environment ... goes on mainly at the nonconscious l e v e l " (p.241). These quotes e s s e n t i a l l y d e s c r i b e an a n t i - i n t r o s p e c t i o n i s t view which c o u l d account f o r the negative f i n d i n g s of t h i s subexperiment. We may be capable of i n t r o s p e c t i n g only on c o n f u s i o n (e.g. CFQ) and not d i s t r a c t i b i l i t y (e.g. Stimulus S e l e c t i v i t y I n v e n t o r y ) . The f i n d i n g s of t h i s subexperiment i n d i c a t e t h a t people are unable to assess or p r e d i c t how d i s t r a c t i b l e they are through s e l f - r e p o r t s . The a r o u s a l t r a i t items d i d not f a r e any b e t t e r i n t h i s i n s t a n c e . Why the a p p a r e n t l y face v a l i d items i n the Stimulus S e l e c t i v i t y Inventory d i d not c o r r e l a t e with our measure of d i s t r a c t i b i l i t y i s not c l e a r . However these data do i n d i c a t e t h a t we must use more s u b t l e measures, perhaps those r e l a t e d to f a c t o r s such as p e r s o n a l i t y , i n t e l l i g e n c e or P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 34 p h y s i o l o g i c a l f a c t o r s such as immediate, s i t u a t i o n a l a r o u s a l , r a t h e r than a r o u s a b i l i t y as a t r a i t , i f we are to p r e d i c t d i s t r a c t i b i l i t y . In the next chapter we w i l l address the issue of s i t u a t i o n a l a r o u s a l as a p o s s i b l e p r e d i c t o r of how d i s t r a c t i b l e an i n d i v i d u a l i s i n an e x t r i n s i c d i s t r a c t i o n t a s k . P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 3 5 Chapter 4 A r o u s a l : A P r e d i c t o r of D i s t r a c t i b i 1 i t y ? A t t e n t i o n as d e s c r i b e d by r e s e a r c h e r s such as Hebb (1955) has two aspects which are r e l e v a n t to t h i s study: stimulus s e l e c t i v i t y and i t s i n t e r a c t i o n with a r o u s a l . Kahneman (1973) a l s o noted t h a t a t t e n t i o n a l a l l o c a t i o n i n t e r a c t s with a r o u s a l . The reader may r e c a l l from Chapter 1 t h a t both of these r e s e a r c h e r s noted the importance of the " s t a t e " of an i n d i v i d u a l i n a t t e n d i n g to s t i m u l i and c a r e f u l r e a d i n g suggests t h a t they were r e f e r r i n g to a r o u s a l s t a t e . T h i s i s r e l e v a n t to the present problem because an i n c r e a s e i n a r o u s a l i s f r e q u e n t l y a r e a c t i o n to exposure to d i s t r a c t o r s ( K r y t e r , 1985). If the presence of d i s t r a c t i n g s t i m u l i a f f e c t s a r o u s a l , and a r o u s a l , i n t u r n , i n t e r a c t s with f o c a l a t t e n t i o n , i t seems reasonable to suggest t h a t a r o u s a l may be a p r e d i c t o r of d i s t r a c t i b i l i t y . We w i l l c o n s i d e r t h i s p o s s i b i l i t y below. Le t us begin with an overview of d i f f e r e n t c o n c e p t u a l i z a t i o n s of a r o u s a l i n order to p i n p o i n t the form(s) of a r o u s a l t h a t may i n f l u e n c e performance on the d i s t r a c t i o n t e s t . Arousal Def ined A r o u s a l i s not e a s i l y o p e r a t i o n a l l y d e f i n e d . I t i s one of P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 3 6 the more d i f f u s e and ambiguous p s y c h o p h y s i o l o g i c a l concepts, even though i t i s commonly used. The n o t i o n of h a b i t u a t i o n , the o r i e n t i n g response and s u b j e c t i v e or c o g n i t i v e m a n i f e s t a t i o n s of a r o u s a l are a l l i n v o l v e d . Since a r o u s a l can be analyzed at many d i f f e r e n t l e v e l s , a l o g i c a l place to s t a r t i s with the p h y s i o l o g i c a l s u b s t r a t e . P h y s i o l o g i c a l B a s i s of Aro u s a l One of the most i n t r i c a t e n e u r a l networks i n the C e n t r a l Nervous System, the R e t i c u l a r A c t i v a t i n g System (RAS), has been r e p e a t e d l y i m p l i c a t e d as an important f a c t o r i n determining our l e v e l of a r o u s a l . T h i s system extends from the s p i n a l cord to the thalamus and i s composed of i n t e r m i n g l e d c e l l bodies and f i b e r s having the appearance of a network ( C a j a l , 1909). T h i s i n t e r c o n n e c t i v e composition e x p l a i n s the d e r i v a t i o n of the term " r e t i c u l u m " which i s l a t i n f o r "network". The r e t i c u l a r core i s surrounded by sensory and motor pathways a l s o c o n t a i n i n g many i n t e r c o n n e c t i o n s . S p e c i f i c a l l y , the RAS r e c e i v e s c o l l a t e r a l axons from ascending pathways whose d e s t i n a t i o n i s i n the co r t e x . E s s e n t i a l l y the RAS i s an i n t e g r a t i n g mechanism t h a t r e g u l a t e s a c t i v i t i e s of the sensory r e c e i v i n g areas of the c o r t e x , the b r a i n stem and the s p i n a l c o r d . (Hernandez-Peon, 1 9 6 6 ) . The i n t e g r a t i o n of the sensory and c o r t i c a l systems i n the RAS has been suggested as p h y s i o l o g i c a l evidence for the ex i s t e n c e of a r e l a t i o n s h i p between a r o u s a l and a t t e n t i o n , and hence may a l s o be a s s o c i a t e d with d i s t r a c t i o n e f f e c t s . F i n d i n g s that r e t i c u l a r l e s i o n s produce unresponsive and P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 37 comatose animals and t h a t r e t i c u l a r s t i m u l a t i o n produces improvement i n r e a c t i o n time performance of monkeys on d i s c r i m i n a t i o n tasks, are s t r o n g evidence for the RAS as a source of a r o u s a l ( L i n d s l e y , 1958). Since monkeys i n t h i s study a l s o d i s p l a y e d improved accuracy on d i s c r i m i n a t i o n tasks with RAS s t i m u l a t i o n , t h i s suggests t h a t the R e t i c u l a r Formation i n c r e a s e s s e l e c t i v e a t t e n t i o n i n a d d i t i o n to a r o u s a l (Thompson, 1975) . Varying Responses to S t i m u l a t i o n : Habituat ion and Or i e n t i n q Response I n v e s t i g a t i n g a r o u s a l from a b e h a v i o r a l p e r s p e c t i v e b r i n g s us back i n t o the realm of i n d i v i d u a l d i f f e r e n c e s most r e l e v a n t to the present study. Everyday o b s e r v a t i o n suggests that people vary i n a t t e n t i o n a l s t y l e s , and the way i n which they respond to s t i m u l a t i o n . For example, some people can e a s i l y ignore the sound of t r a f f i c while c o n c e n t r a t i n g on a task while others f i n d t h i s to be impossible. I f we view these d i f f e r e n c e s as a product of d i f f e r e n c e s i n a r o u s a b i l i t y , i t i s u s e f u l to c o n s i d e r the p o s s i b i l i t y that we are d e a l i n g with i n d i v i d u a l d i f f e r e n c e s i n h a b i t u a t i o n and o r i e n t i n g responses. H a b i t u a t i o n has been d e f i n e d as the number of stimulus p r e s e n t a t i o n s necessary fo r e x t i n c t i o n of an a t t e n t i o n a l response (Duffy, 1957, 1962). Those a d v e r s e l y a f f e c t e d by noise and d i s t r a c t o r s are p o s s i b l y slower to habituate and t h e r e f o r e poorer at a t t e n d i n g over an extended time p e r i o d . Support f o r such i n d i v i d u a l d i f f e r e n c e s i n h a b i t u a t i o n i s found in P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 38 p h y s i o l o g i c a l r e c o r d i n g s of b o d i l y responses such as heart r a t e , EEG, G a l v a n i c Skin Responses (GSR). While repet i t ion of s t i m u l a t i o n r e s u l t s i n h a b i t u a t i o n , changes i n s t i m u l a t i o n evoke a d i f f e r e n t response known as the " o r i e n t i n g response". The or i e n t i n g response i s a b r i e f response to s t i m u l a t i o n that improves an i n d i v i d u a l ' s c a p a c i t y f o r r e c e i v i n g i n f o r m a t i o n from the environment. Sokolov (1963) d e s c r i b e s the o r i e n t i n g response as a r e f l e x i v e response to a p o t e n t i a l l y i n f o r m a t i v e and r e l a t i v e l y novel s t i m u l u s . An i n d i v i d u a l prone to d i s t r a c t i o n presumably i s l e s s d i s c r i m i n a t i n g to the s t i m u l i t o which they o r i e n t . The c h a r a c t e r i s t i c s of inputs t h a t produce the o r i e n t i n g response were l a b e l e d by Berlyne (1968) as " c o l l a t i v e v a r i a b l e s " . These i n c l u d e sudden changes i n i n t e n s i t y to which the organism i s unaccustomed, changes i n the t i m i n g of the i n p u t s , and changes i n the ground i n which a stim u l u s f i g u r e appears ( s p e c i f i c a l l y when inputs are sc a r c e , s u r p r i s i n g , complex, and/or n o v e l ) . The c o l l a t i v e c h a r a c t e r i s t i c s a l s o d e f i n e the concept " i n f o r m a t i o n " ; thus, i t i s p o s s i b l e to t r e a t organisms as " i n f o r m a t i o n p r o c e s s i n g systems" where input i s matched a g a i n s t some r e s i d u a l experience (Pribram 1975; Sokolov, 1969). O r i e n t i n g i s t r i g g e r e d by a marked change i n the stimulus set i n the environment; t h i s corresponds with the p e r c e p t i o n of novel i n f o r m a t i o n . Those i n d i v i d u a l s who have a high t h r e s h o l d f o r o r i e n t i n g (or who habituate q u i c k l y ) not onl y are l e s s apt to be aroused but are l e s s apt to be d i s t r a c t e d . However, as we s h a l l P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 39 see below, the a c t u a l e f f e c t s of a r o u s a l on performance may be much more complex then the preceding argument suggests. A r o u s a l , D i s t r a c t ion and Performance Hebb (1955) suggested that r e s e a r c h e r s consider the f a c t t h a t every stimulus has both a cue and an a c t i v a t i n g f u n c t i o n and t h a t t h i s dual c h a r a c t e r i s t i c may have c o n t r a d i c t o r y e f f e c t s on performance i n an experiment where d i s t r a c t o r s are p r e s e n t . Let us r e c a l l t h a t " d i s t r a c t o r s " r e f e r to s t i m u l i which are i r r e l e v a n t and p o t e n t i a l l y o b t r u s i v e to the task to be performed. Because d i s t r a c t o r s have an impact both on the a b i l i t y to attend to a task (Hebb's cue f u n c t i o n ) and the a r o u s a l l e v e l of the person performing the task (Hebb's a c t i v a t i o n f u n c t i o n ) , i t i s important to c o n s i d e r the c o n t r i b u t i o n of both to performance. ( S i d d l e & Marigan, 1971). The g o a l of t h i s s e c t i o n i s to convince the reader t h a t a complicated i n t e r p l a y may e x i s t between a r o u s a l and d i s t r a c t i o n . In t u r n t h i s may be r e f l e c t e d i n task performance under d i s t r a c t i o n c o n d i t i o n s . If t h i s i s t r u e , then a r o u s a l may be an e f f e c t i v e p r e d i c t o r of d i s t r a c t i b i l i t y . F i r s t I w i l l d i s c u s s how the ambiguity and complexity surrounding the n o t i o n of a r o u s a l can manifest i t s e l f i n seemingly c o n t r a d i c t o r y performance e f f e c t s . High a r o u s a l has been found to both improve and impair performance ( K r y t e r , 1985; Eysenck, 1982; Mehrabian, 1976; Mehrabian & R u s s e l l , 1974b; Easterbrook, 1959). To r e s o l v e such a p p a r e n t l y P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 40 c o n t r a d i c t o r y performance f i n d i n g s , three models of a r o u s a l and performance are presented: the Information Rate-Arousal  h y p o t h e s i s . the Response-Arousal Theory and the Yerkes-Dodson Law. These models provide d i f f e r e n t e x p l a n a t i o n s of performance which i s i n f l u e n c e d by a r o u s a l and d i s t r a c t i o n . Information Rate - A r o u s a l Theory Accor d i n g to the Information Rate-Arousal Theory, a r o u s a l  changes are caused by d i s t r a c t i b i l i t y . Stimulus s c r e e n e r s ( n o n - d i s t r a c t i b l e i n d i v i d u a l s ) s e l e c t out i r r e l e v a n t i n f o r m a t i o n which i n t u r n lowers t h e i r a r o u s a l . A decrease i n a r o u s a l occurs because the i n d i v i d u a l i s p r o c e s s i n g a manageable amount of i n f o r m a t i o n . T h i s c o n t r a s t s with non-screeners, who respond to i r r e l e v a n t as w e l l as r e l e v a n t i n f o r m a t i o n which i n t u r n e l e v a t e s t h e i r a r o u s a l l e v e l (Mehrabian, 1976; Mehrabian & R u s s e l l , 1974b). T h i s occurs because the nonscreener i s bombarded with too much i n f o r m a t i o n and hence he must process more then he can manage. By viewing the presence of d i s t r a c t i n g s t i m u l i as the t r i g g e r for aro u s a l changes, it- would seem reasonable to use a r o u s a l as a p r e d i c t o r of performance decrement due to d i s t r a c t i b i l i t y . Thus a r o u s a l and d i s t r a c t i b i l i t y would be expected to vary together i n i n d i v i d u a l s because i n d i v i d u a l d i f f e r e n c e s i n s e l e c t i v i t y ( s t i mulus s c r e e n i n g a b i l i t y ) e l i c i t changes i n a r o u s a l . Response-Arousal Theory The Response-Arousal th e o r y makes s i m i l a r p r e d i c t i o n s to P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 41 the Information Rate t h e o r y but the reasoning i s r e v e r s e d . According to Kr y t e r (1985), an advocate of the Response-Arousal theory, d i f f e r e n c e s i n a r o u s a b i l i t y cause d i f f e r e n c e s i n s e l e c t i v i t y , r a t h e r than the other way around. T h i s r e a s o n i n g can be used to p r e d i c t not o n l y a d i r e c t r e l a t i o n s h i p between a r o u s a b i l i t y and d i s t r a c t i b i l i t y but a l s o can be used t o p r e d i c t f a c i l i t a t i o n of performance due to a r o u s a l e f f e c t s . Thus a r o u s a l e i t h e r can cause d i s t r a c t i o n v i a response i n t e r f e r e n c e or enhanced performance by a c t i v a t i n g a p p r o p r i a t e response systems. T h i s n o t i o n was forshadowed by Hebb (1955) who argued that i n c r e a s e s i n a r o u s a l can a c t i v a t e a n e u r a l network a s s o c i a t e d with a p a r t i c u l a r a t t e n t i o n - r e s p o n s e system. I f the response i s compatible with the task, improved performance occurs and i f the response i s incompatible, impaired performance occurs. The i n t r o d u c t i o n of task/response c o m p a t i b i l i t y as a mediating v a r i a b l e i n d e a l i n g with a r o u s a l , b r i n g s us t o an ol d e r and s t i l l h i g h l y debated theory of a r o u s a l and performance: the Yerkes-Dodson Law. Yerkes-Dodson Law The Yerkes-Dodson Law (1908), l i k e the Arousal-Response Theory, p r e d i c t s both impaired and f a c i l i t a t e d performance under a p p r o p r i a t e c o n d i t i o n s of a r o u s a l . This law p o s t u l a t e s an inver t e d - U shaped curve of performance p r o f i c i e n c y when p l o t t e d a g a i n s t a r o u s a l l e v e l . T h i s inverted-U r e l a t i o n s h i p p r e d i c t s t h a t a moderate degree of a r o u s a l w i l l produce optimal P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 42 performance and a r o u s a l l e v e l s t h at are too high or too low w i l l r e s u l t i n d i m i n i s h e d performance. The type of a r o u s a l captured by the i n v e r t e d - U curve i s the s t a t e of e x c i t a b i l i t y or wakefulness. T h i s aspect of a r o u s a l i s p o r t r a y e d as v a r y i n g from s l e e p through i n c r e a s i n g stages of wakefulness to extreme a l e r t n e s s and d i s o r g a n i z a t i o n . Optimal p s y c h o l o g i c a l f u n c t i o n i n g i s c o n s i d e r e d to occur i n moderate s t a t e s of a r o u s a l , that i s , between the two extremes of s l e e p and d i s o r g a n i z a t i o n (Hebb, 1955). A r o u s a l l e v e l s above optimal i n t e r f e r e with execution of a task, while lower l e v e l s are i n s u f f i c i e n t f o r adequate performance (Yerkes & Dodson, 1908). Kahneman (1973) d e s c r i b e s a s i m i l a r inverted-U shaped r e l a t i o n s h i p between a r o u s a l l e v e l and a t t e n t i o n . C e n t r a l to h i s model i s the n o t i o n t h a t a t t e n t i o n depends on the i n d i v i d u a l ' s c a p a c i t y to i n v e s t e f f o r t i n the a t t e n t i o n a l process; t h i s a b i l i t y , i n t u r n , i s l i n k e d to a r o u s a l l e v e l . I f a r o u s a l i s too high, a t t e n t i o n a l focus becomes too narrow and hence u n s t a b l e . I f a r o u s a l i s too low, a t t e n t i o n i s a l s o unstable but t h i s time because the focus i s too wide. Therefore we can conclude that a r o u s a l i s n e i t h e r c o n s i s t e n t l y f a c i l i t a t i n g nor c o n s i s t e n t l y d i s r u p t i n g . Which e f f e c t i s observed depends upon the l e v e l of a r o u s a l . Because p r e c i s e l e v e l s of a r o u s a l are d i f f i c u l t to determine as we s h a l l see i n the f o l l o w i n g s e c t i o n , the Yerkes-Dodson c o n c e p t u a l i z a t i o n of a r o u s a l and performance has undergone severe c r i t i c i s m and r e i n t e r p r e t a t i o n (Brunia, 1979). P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 43 F o r t u n a t e l y f o r us, the goal of t h i s t h e s i s i s not to t e s t the inv e r t e d - U r e l a t i o n s h i p . Since we are concerned with i n d i v i d u a l d i f f e r e n c e s i n performance, however, and s i n c e a r o u s a l seems to a f f e c t performance, i t i s important t h a t we co n s i d e r i t s e f f e c t s on our t a s k . F i r s t , however, we must address the task of f i n d i n g an adequate measure of a r o u s a l . Measuring Ar o u s a l Researchers have had d i f f i c u l t y i n e s t a b l i s h i n g a s i n g l e optimal measure of a r o u s a l due to the f a c t t h a t many systems and p h y s i o l o g i c a l c o r r e l a t e s are i n v o l v e d (Thayer, 1978; Brunia, 1979; K r y t e r , 1985). Sta t e s of b e h a v i o r a l , autonomic, e l e c t r o c o r t i c a l and biochemical a r o u s a l are o f t e n d i s s o c i a t e d from one another (Lacey, 1967). T h i s d i s s o c i a t i o n i s supported i n the f i n d i n g t h a t d i f f e r e n t p h y s i o l o g i c a l measures of a r o u s a l (heart r a t e , s k i n conductance and EEG) u s u a l l y c o r r e l a t e only .2 to .3 with each other (Thayer, 1978). There are a l s o some oc c a s i o n s when p a r t i c u l a r measures i n d i c a t e increased a r o u s a l while others i n d i c a t e decreased a r o u s a l . These low c o r r e l a t i o n s and the o f t e n c o n t r a d i c t o r y a r o u s a l measures based upon d i f f e r e n t somatic systems i n d i c a t e t h a t s i n g l e component measures of a r o u s a l , are not v a l i d as a general index of a r o u s a l . A f u r t h e r problem i s t h a t separate a r o u s a l systems are not o n l y d i s s o c i a t e d from one another but they are a l s o o f t e n poor p r e d i c t o r s of the b e h a v i o r a l and s u b j e c t i v e m a n i f e s t a t i o n s of a r o u s a l . Thayer (1978) addressed t h i s d i f f e r e n t i a t e d view of P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 44 a r o u s a l and attempted to d e r i v e a s e l f - r e p o r t a c t i v a t i o n s c a l e which d i r e c t l y tapped i n t o the b e h a v i o r a l and s u b j e c t i v e l y d i s c e r n a b l e aspects of a r o u s a l . His i n v e n t o r y which i s r e f e r r e d to as the " A c t i v a t i o n - D e a c t i v a t i o n - A d j e c t i v e c h e c k l i s t " i s used i n the present study to assess the a r o u s a l s t a t e of an i n d i v i d u a l . Thayer's s u b j e c t i v e assessment of a r o u s a l s t a t e s has been v a l i d a t e d a g a i n s t s e v e r a l d i r e c t measures. I t i s s i g n i f i c a n t l y c o r r e l a t e d with four p h y s i o l o g i c a l measures (even though they do not s i g n i f i c a n t l y c o r r e l a t e among themselves). These measures in c l u d e h eart r a t e , s k i n r e s i s t a n c e , muscle a c t i o n p o t e n t i a l and f i n g e r blood volume (Thayer, 1967, 1970). One f a c t o r t h a t may account f o r the high c o r r e l a t i o n s between the separate p h y s i o l o g i c a l measures and the Thayer s e l f - r e p o r t measure i s that i n f o r m a t i o n about b o d i l y a c t i v i t y i s a v a i l a b l e from the co r t e x which a c t s as an i n t e g r a t i n g mechanism f o r in f o r m a t i o n r e c e i v e d from v a r i o u s p h y s i o l o g i c a l systems (Eysenck, 1975, p.441). A d d i t i o n a l e x p l a n a t i o n s for a g l o b a l measure (such as the Thayer) being s u p e r i o r to i s o l a t e d p h y s i o l o g i c a l measures of a r o u s a l i n c l u d e : 1) Many s u b j e c t s show unique p a t t e r n s of p h y s i o l o g i c a l responsiveness 2) D i f f e r e n t systems may act i n compensatory f a s h i o n i n order to maintain homeostatic balance 3) Systems have d i f f e r e n t response l a t e n c i e s and times f o r reaching response l i m i t s and 4) Some systems may be more r e p r e s e n t a t i v e of t o t a l organismic a c t i v a t i o n than others (Duffy, 1962). T h i s P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 45 study avoids these problems by using Thayer's g l o b a l a r o u s a l measure to d e t e c t b e h a v i o r a l consequences of a r o u s a l . The u s e f u l n e s s of Thayer's s e l f r e p o r t a l s o has been shown i n a number of performance t e s t s which are known to e l i c i t a r o u s a l ( M a r t i n & Venables, 1980). These experiments demonstrate an absence of i n t e r c o r r e l a t i o n s between p h y s i o l o g i c a l measures d u r i n g p a s s i v e (e.g. r e s t i n g ) and a c t i v e (e.g. c o u n t i n g backwards) c o n d i t i o n s . T h i s c o n t r a s t s with the Thayer s e l f - r e p o r t which not onl y was s i g n i f i c a n t l y c o r r e l a t e d with a composite of v a r i o u s p h y s i o l o g i c a l measures but a l s o was s u c c e s s f u l i n d i s c r i m i n a t i n g between a c t i v e and pas s i v e c o n d i t i o n s . Another pragmatic reason f o r us i n g the Thayer s e l f - r e p o r t i s t h a t i t e l i m i n a t e s the need f o r apparatus and can be e a s i l y a d m i n i s t e r e d t o a l a r g e group of s u b j e c t s . More imp o r t a n t l y , t h i s s e l f - r e p o r t appears to be an i n t e g r a t i v e v a r i a b l e more r e p r e s e n t a t i v e of a g e n e r a l s t a t u s of b o d i l y a c t i v a t i o n than any s i n g l e p s y c h o p h y s i o l o g i c a l v a r i a b l e . In sum i t i s an e f f e c t i v e measure of phenomenological i n t e g r a t i o n of ongoing autonomic and somatic a c t i v i t y ( Martin & Venables, 1980). P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 46 Method  Subjects The 308 s u b j e c t s who completed the d i s t r a c t i o n task i n the f i r s t subexperiment, served as s u b j e c t s i n t h i s subexperiment. In a d d i t i o n , the 36 s u b j e c t s who r e c e i v e d three s e c t i o n s of the no d i s t r a c t o r search task served as the c o n t r o l group here. Apparatus and Procedure The d i s t r a c t i o n t e s t used i n the f i r s t subexperiment was used i n t h i s subexperiment. Immediately preceding and immediately f o l l o w i n g the d i s t r a c t i o n t e s t , the Thayer Arousal Inventory was completed by s u b j e c t s to assess the impact of the d i s t r a c t o r s and/or the t e s t on a r o u s a l s t a t e . Thayer's v a l i d a t e d s e l f - r e p o r t a d j e c t i v e c h e c k l i s t appears i n Appendix C. Thayer's i n v e n t o r y i s an e x t e n s i o n of Nowlis' (1961, 1965) s e l f - d e s c r i p t i v e mood measures. From t h e i r work i t became c l e a r that a s e l f - r e p o r t format can be used to provide an e a s i l y scored measure of t r a n s i e n t l e v e l s of a c t i v a t i o n . The response format was changed to " d e f i n i t e l y . . . , moderately..., s l i g h t l y . . . , d e f i n i t e l y do not f e e l at t h i s moment" i n response to R u s s e l l ' s (1979) c r i t i c i s m . The measures of a r o u s a l s t a t e p rovided by the Thayer i n c l u d e : a p r e - t e s t a r o u s a l l e v e l (Pre-Arousal) and a p o s t - t e s t a r o u s a l l e v e l ( P o s t - A r o u s a l ) . Computation of a r o u s a l s t a t e i n v o l v e s o b t a i n i n g a composite of the i n d i v i d u a l items on each s e l f - r e p o r t . A high composite P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 47 score corresponds with a high a r o u s a l s t a t e . The change i n a r o u s a l caused by performing the d i s t r a c t i o n t e s t (Arousal change) i s obtained from s u b t r a c t i n g P o s t - A r o u s a l from P r e - A r o u s a l . Thus the l a r g e r t h i s d i f f e r e n c e , the grea t e r i s the impact of the d i s t r a c t i o n task on an i n d i v i d u a l ' s a r o u s a l s t a t e . R e s u l t s and D i s c u s s i o n In order to determine the i n t e r r e l a t i o n s h i p between a r o u s a l and d i s t r a c t i o n , the d i s t r a c t i b i l i t y scores were compared with the a r o u s a l s c o r e s . Simply performing the matching p a r t of the d i s t r a c t i o n t e s t does i n c r e a s e the l e v e l of a r o u s a l . T h i s i s d e p i c t e d i n F i g u r e 3 where, P o s t - A r o u s a l i s s i g n i f i c a n t l y g r e a t e r than Pre-Arousal f o r the experimental (t=8.1 p<.001) and c o n t r o l groups (t=6.4 p<.001) . Since there were no measures of a r o u s a l i n between the v i s u a l , a u d i t o r y and no d i s t r a c t o r s e c t i o n s , the impact on a r o u s a l a t these i n t e r m e d i a r y p o i n t s cannot be assessed. Nor can the impact of the separate d i s t r a c t o r s be assessed. N e v e r t h e l e s s , we can s a f e l y a t t r i b u t e the i n c r e a s e i n a r o u s a l to e i t h e r the d i s t r a c t o r s or the t e s t i t s e l f . To c o n t r o l f o r such task alone a r o u s a l e f f e c t s we had i n c l u d e d a group which had no d i s t r a c t o r s but performed the three s e c t i o n s of the matching task . For t h i s group, the mean a r o u s a l change was 13.1 as compared to the experimental groups whose average was 19.0. That P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 48 the presence of d i s t r a c t o r s c o n t r i b u t e d to the increase i n f i n a l a r o u s a l s t a t e i s evident from a s i g n i f i c a n t d i f f e r e n c e i n the p o s t - t e s t a r o u s a l scores which e x i s t s between the v i s u a l / a u d i t o r y experimental group and the c o n t r o l group (t=5.9 p<.001) . I n s e r t F i g u r e 4 A rousal seems to have a d i r e c t e f f e c t on performance i n g e n e r a l . P o s t - t e s t a r o u s a l and change i n a r o u s a l l e v e l are s i g n i f i c a n t l y r e l a t e d to the number of c o r r e c t responses for a l l s e c t i o n s of the matching task as shown i n Table 3. You may r e c a l l from Chapter 2 that the d i s t r a c t i b i l i t y scores were sta n d a r d i z e d so as to e l i m i n a t e p o t e n t i a l confounds from order e f f e c t s . For t h i s same reason, the number c o r r e c t scores were a l s o s t a n d a r d i z e d . Hence these Z-score t r a n s f o r m a t i o n s s t a n d a r d i z e the mean number c o r r e c t a c r o s s the experimental groups ( v i s u a l / a u d i t o r y and a u d i t o r y / v i s u a l ) to the same s c a l e so t h a t we may have an unconfounded method of examining the r e l a t i v e performance between i n d i v i d u a l s . The p o s i t i v e c o r r e l a t i o n s i n t h i s t a b l e i n d i c a t e t h a t those who perform b e t t e r on the d i s t r a c t i o n t e s t have a higher f i n a l a r o u s a l s t a t e . I n s e r t Table 3 However the c o r r e l a t i o n s between a r o u s a l l e v e l (or change i n a r o u s a l ) and performance decrement under d i s t r a c t i o n were a l l n o n s i g n i f i c a n t as shown i n Table 4. T h i s suggests that we may r e j e c t the hypothesis t h a t d i s t r a c t i b i l i t y i s p r e d i c t a b l e on the 48a Figure 4 65-i CONTROL EXPERIMENTAL Legend ea PRE-AROUSAL SB POST-AROUSAL Table 3 Arousal and The D i s t r a c t i o n Task Pearson C o r r e l a t i o n s P r e - A r o u s a l P o s t - A r o u s a l A r o u s a l Change Standardized #Correct i n : C o n t r o l V i s u a l A u d i t o r y -.01 -.03 .02 .19** .17** .20*** .15** .16** .13* * P<.05 ** P<.01 *** p<.001 P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 49 b a s i s of a r o u s a l i n c r e a s e s due to the presence of d i s t r a c t o r s . I n s e r t Table 4 Although a r e l a t i o n s h i p e x i s t s between a r o u s a l , performance and the presence of d i s t r a c t o r s , d i s t r a c t i b i l i t y i t s e l f , measured as performance decrement i n the s e c t i o n s c o n t a i n i n g d i s t r a c t o r s , appears to be independent of a r o u s a l e f f e c t s . A p o s s i b l e e x p l a n a t i o n f o r an absence of a l i n k between a r o u s a l and d i s t r a c t i b i l i t y as was p r e d i c t e d by Kahneman (1973), K r y t e r (1985) and Mehrabian (1976), i s that the d i s t r a c t o r s used i n t h i s study may not have e l i c i t e d a s t r o n g enough a r o u s a l response or the d i s t r a c t i o n task was too simple to be impaired by a r o u s a l changes. Mehrabian and R u s s e l l (1974) e x p l i c i t l y s t a t e d that d i s t r a c t i n g cues must be introduced d u r i n g performance of a moderately or h i g h l y complex task. I n d i v i d u a l d i f f e r e n c e s i n performance are attenuated on simple t a s k s , which i s e x a c t l y what the d i s t r a c t i o n t e s t i s . I t i s a l s o p o s s i b l e t h a t performance might not be measuring s e l e c t i v i t y a c c o r d i n g to Mehrabian's d e f i n i t i o n of the term which r e f e r s to the a b i l i t y to s e l e c t out r e l e v a n t s t i m u l i i n such a way as to reduce a r o u s a l . T h i s i s supported by the absence of a r e l a t i o n s h i p (found i n chapter 3) between the Stimulus S e l e c t i v i t y Inventory and the d i s t r a c t i o n t e s t . R e c a l l t h a t some items from Mehrabian's Inventory were included in the Stimulus S e l e c t i v i t y Inventory. Hence, Mehrabian's s e l e c t i v i t y appears to be a d i f f e r e n t phenomenon from d i s t r a c t i b i l i t y t h a t i s measured by the d i s t r a c t i o n t e s t . Table 4 D i s t r a c t i b i l i t y and A r o u s a b i l i t y  Pearson C o r r e l a t i o n s A r o u s a l : Pre Post Change Standardized Scores: V i s u a l D i s t r a c t i b i l i t y .06 .01 -.04 A u d i t o r y D i s t r a c t i b i l i t y -.06 -.09 -.02 A l l n o n - s i g n i f i c a n t P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 50 On the b a s i s of the measures used here, however we can conclude t h a t there i s no r e l a t i o n s h i p between a r o u s a l changes caused by i r r e l e v a n t s t i m u l i and performance decrement under such c o n d i t i o n s of d i s t r a c t i o n . Of course, on the b a s i s of our d i s c u s s i o n s above, i t may be wise to l i m i t our a s s e r t i o n s to the present task, r a t h e r than g e n e r a l i z i n g across t a s k s . On the other hand, the r e s u l t s presented above are c o n s i s t e n t with our f i n d i n g i n Chapter 3, t h a t there was no r e l a t i o n s h i p between d i s t r a c t i b i l i t y and a r o u s a b i l i t y , viewed as a t r a i t , and measured by Coren's (1988) A r o u s a l P r e d i s p o s i t i o n S c a l e . P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 51 Chapter 5 P e r s o n a l i t y : A p r e d i c t o r of d i s t r a c t i b i l i t y ? I t i s w e l l known t h a t many s t i m u l i t r i g g e r a s i m i l a r response i n d i f f e r e n t people. For example an unexpected 100 dB noise t r i g g e r s a s t a r t l e response i n most i n d i v i d u a l s with i n t a c t h e a r i n g . While people do share common response p a t t e r n s to n o i s e , they possess unique ones too. I n d i v i d u a l d i f f e r e n c e s i n responsiveness to the environment have been demonstrated i n a number of Berlyne's experiments (1960) ( c i t e d i n Gray, 1964b). Many of these d i f f e r e n c e s are c h a r a c t e r i z e d as p e r s o n a l i t y t r a i t s and many of these t r a i t s have been d e s c r i b e d i n terms of d i f f e r e n c e s i n a r o u s a l . In Chapter 4 we found t h a t a r o u s a l s t a t e i s u n r e l a t e d to d i s t r a c t i b i l i t y , while i n Chapter 3, where we measured a r o u s a b i l i t y as a b e h a v i o r a l p r e d i s p o s i t i o n , we found a s i m i l a r absence of a s i g n i f i c a n t r e l a t i o n s h i p . In t h i s chapter we w i l l attempt to see i f other p e r s o n a l i t y v a r i a b l e s are l i n k e d to s u s c e p t i b i l i t y to d i s t r a c t i o n . The p e r s o n a l i t y t r a i t s t e s t e d i n c l u d e e x t r a v e r s i o n , s e n s a t i o n seeking, obsessive-compulsive and Type A behavior. E x t r a v e r s i o n / I n t r o v e r s ion P r e d i c t i n g i n d i v i d u a l d i f f e r e n c e s i n a t t e n t i o n with measures of e x t r a v e r s ion and i n t r o v e r s i o n was i n i t i a t e d by Eysenck (1967). He d e f i n e d an e x t r a v e r t e d i n d i v i d u a l as outgoing P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 52 and s o c i a b l e while an i n t r o v e r t e d i n d i v i d u a l tended to be withdrawn and s e l f - c o n t a i n e d . Eysenck (1967) used Pavlov's (1927) c o n s t r u c t of i n t e r n a l i n h i b i t i o n and e x c i t a t i o n as w e l l as H u l l ' s (1929) r e a c t i v e i n h i b i t i o n to f u r t h e r d e s c r i b e the e x t r a v e r s i o n / i n t r o v e r s i o n p e r s o n a l i t y t r a i t s . I n h i b i t o r y p o t e n t i a l r e f e r s to an i n d i v i d u a l ' s n e u r a l a b i l i t y or tendency to ignore s t i m u l a t i o n . E x c i t a t o r y p o t e n t i a l r e f e r s to the a b i l i t y or tendency to be i n f l u e n c e d by s t i m u l a t i o n . According to Eysenck (1967) e x t r a v e r t e d i n d i v i d u a l s can be c h a r a c t e r i z e d as having weak e x c i t a t o r y and st r o n g r e a c t i v e i n h i b i t o r y p o t e n t i a l whereas i n t r o v e r t e d i n d i v i d u a l s can be c h a r a c t e r i z e d as having s t r o n g e x c i t a t o r y and weak i n h i b i t o r y p o t e n t i a l s . These e f f e c t s are manifested i n a slower and weaker responding n e u r a l system i n e x t r a v e r t s and a f a s t e r and stronger stimulus a r o u s a l response i n i n t r o v e r t s . T h i s d i f f e r e n c e p r e d i c t s c e r t a i n d i f f e r e n c e s i n behavior i f one recognizes t h a t a l i n k between n e u r a l a c t i v i t y and overt behavior e x i s t s . For instance t h i s t h e o r y would p r e d i c t t h a t i n t r o v e r t s would be more impaired by d i s t r a c t o r s because of t h e i r s t r o n g tendency to be i n f l u e n c e d by s t i m u l a t i o n and t h e i r weak a b i l i t y to ignore s t i m u l a t i o n . Support f o r Eysenck's e x p l a n a t i o n of i n t r o v e r s i o n versus e x t r a v e r s i o n was found i n drug s t u d i e s , where a person's p o s i t i o n on the i n t r o v e r s i o n / e x t r a v e r s i o n dimension was s h i f t e d by a r o u s a l a l t e r i n g drugs. Stimulant drugs produce increased i n t r o v e r s i o n while depressant drugs produce a s h i f t toward e x t r a v e r s i o n . P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 53 Because e x t r a v e r t s have a ne u r a l system that generates n e u r a l i n h i b i t i o n more q u i c k l y , we would a l s o expect i n t r o v e r t s to be more p e r c e p t u a l l y s e n s i t i v e than e x t r o v e r t s . C o n s i s t e n t with t h i s p r e d i c t i o n , s t u d i e s have demonstrated t h a t i n t r o v e r t s have a lower average t h r e s h o l d for v i s i o n ( S i d d l e , M o r r i s h , White and Mangen, 1969) and hea r i n g (Stelmack and Campbell, 1974; Stelmack, Achorn & Michaud, 1977). In terms of the problem under c o n s i d e r a t i o n here, we might expect that t h i s g r e a t e r s e n s i t i v i t y i n i n t r o v e r t s to manifest i t s e l f under c o n d i t i o n s of d i s t r a c t i o n with i n t r o v e r t s being more d i s t r a c t i b l e . Because of t h e i r higher t h r e s h o l d , i n t r o v e r t s are expected to have impaired performance on the d i s t r a c t i o n t e s t d u r i n g exposure to d i s t r a c t o r s . Sensation Seek inq A l t e r n a t i v e l y , d i s t r a c t i b i l i t y may be l i n k e d to s e n s a t i o n  seek inq r a t h e r than ge n e r a l e x t r a v e r s i o n . Zuckerman (1979 ) d e f i n e s s e n s a t i o n seeking as the need for v a r i e d , novel and complex s e n s a t i o n s and experiences and the w i l l i n g n e s s to take p h y s i c a l and s o c i a l r i s k s f o r the sake of such an experience. A high s e n s a t i o n seeker chooses s t i m u l i that maximize i n t e r n a l s e n s a t i o n s . These s t i m u l i are c h a r a c t e r i z e d by n o v e l t y , v a r i e t y (change), complexity and r i s k i n e s s . The s e n s a t i o n seeker a l s o tends to hab i t u a t e f a s t e r to s t i m u l i than does an i n d i v i d u a l low i n s e n s a t i o n seeking. We would expect f o r t h i s to manifest i t s e l f i n performance on the d i s t r a c t i o n t e s t with high P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 54 s e n s a t i o n seekers being more d i s t r a c t i b l e so as to counter t h e i r tendency to h a b i t u a t e . Obsessive-Compulsiveness The standard c l i n i c a l view of the term obse s s i o n i s to be " e x c e s s i v e l y concerned with some idea or a c t i v i t y " and compulsion i s the " p r o p e n s i t y to c a r r y out some a c t i v i t y with p a r t i c u l a r c a r e " (Rachman, 1980, p.3). T h i s d e s c r i p t i o n together with s t u d i e s which demonstrate t h a t obsessive i n d i v i d u a l s have a narrow a t t e n t i o n a l f i e l d suggest that an obsessive i n d i v i d u a l may be n o n - d i s t r a c t i b l e (Wachtel, 1967 and Shapiro, 1965). Viewing a t t e n t i o n as a beam of l i g h t helps h i g h l i g h t how obsessive/compulsive versus normal i n d i v i d u a l s d i f f e r i n a t t e n t i o n and d i s t r a c t i o n . A t t e n t i o n , l i k e a beam of l i g h t , possesses many q u a l i t i e s such as width, i n t e n s i t y and extent of scanning (Hernandez-Peon, 1966). An obsessive i n d i v i d u a l , can be c h a r a c t e r i z e d by t h i s analogy, as having an a b i l i t y to scan t h e i r a t t e n t i o n a l s p o t l i g h t over a wide f i e l d . The s p o t l i g h t i t s e l f however i s narrow and s h a r p l y focused even though i t passes over a wide f i e l d (Wachtel 1967, p.418). Hence the broader range of scanning coupled with a narrow s p o t l i g h t leads to the p r e d i c t i o n that obsessives are more d i s t r a c t i b l e . Gordon (1985) and Broadbent (1986) showed t h a t obsessive i n d i v i d u a l s have higher scores on Broadbent's 1982 " C o g n i t i v e F a i l u r e Q u e s t i o n n a i r e " which p u r p o r t e d l y measures d i s t r a c t i b i l i t y and other f a i l u r e s of c o n c e n t r a t i o n . Broadbent (1986) a l s o found that the tendency to do w e l l at h i s search P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 55 task was i n v e r s e l y c o r r e l a t e d with the o b s e s s i o n a l p e r s o n a l i t y . According to these f i n d i n g s obsessive i n d i v i d u a l s appeared to be more d i s t r a c t i b l e i n the search task c o n d i t i o n . No d i f f e r e n t i a l performance occurred i n the f i l t e r t a s k s . As was mentioned p r e v i o u s l y , our d i s t r a c t i o n task i s more s i m i l a r to Broadbent's search task then to h i s f i l t e r t a s k . We might expect then t h a t obsessive-compulsiveness w i l l be i n v e r s e l y r e l a t e d to d i s t r a c t i b i l i t y , even though t h i s runs counter to the d e s c r i p t i o n of an obsessive i n d i v i d u a l simply posessing a narrow a t t e n t i o n a l f i e l d (Gordon, 1985). Type A/Type B P e r s o n a l i t y The Type A coronary-prone behavior p a t t e r n has been d e f i n e d as an "action-emotion complex" (Friedman & Rosenman, 1974 p.67) that can be observed i n any person who i s a g g r e s s i v e l y i n v o l v e d i n * c h r o n i c , i n c e s s a n t s t r u g g l e to accomplish more and more i n l e s s and l e s s time (Houston, 1987). G e n e r a l l y a Type A person i s c h a r a c t e r i z e d as impatient, having an e x c e s s i v e d e s i r e to achieve ( G l a s s , 1977) and having a c h r o n i c sense of time urgency (Burnham, Pennebaker & G l a s s , 1975). Other r e l a t e d q u a l i t i e s of the Type A i n d i v i d u a l i n c l u d e : an enhanced sense of competitiveness and a g g r e s s i o n (Carver & G l a s s , 1978), an o v e r l y c o n s c i e n t i o u s , work-oriented and punctual o r i e n t a t i o n and a tendency to concentrate on more than one a c t i v i t y at a time (Matthews, 1982). Although Type B i s not the a n t i t h e s i s of the Type A, many of the q u a l i t i e s do seem to be p o l a r o p p o s i t e s . For example, P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 56 Type B i n d i v i d u a l s tend to be non-competitive, r e l a x e d , easy-going, p a t i e n t and have an unhurried and calm demeanor. A Type B i n d i v i d u a l may be goal and achievement o r i e n t e d which suggests t h a t Type A versus Type B p e r s o n a l i t i e s are not simply o p p o s i t e s . Support f o r an ov e r l a p between Type A's and Type B's e x i s t s i n r e s e a r c h which made use of the Gough-Adjective C h e c k l i s t (Herman, Blumental, Black & Chesney, 1981). T h i s study found t h a t s e l f r a t e d a d j e c t i v e s l i k e a c h i e v e m e n t - o r i e n t a t i o n and ambitiousness d i d not d i s c r i m i n a t e w e l l between Type A's and B's. The c r u c i a l f e a t u r e of the Type A/Type B d i s t i n c t i o n r e l e v a n t to t h i s study i s the accuracy and r a t e a t which tasks are performed by these i n d i v i d u a l s . The opening d e s c r i p t i o n of Type A behavior suggests t h a t i n d i v i d u a l s prone to such behavior, w i l l a c c e l e r a t e t h e i r performance on the d i s t r a c t i o n task s i n c e t h e i r p h y s i c a l and mental a c t i v i t y are a c c e l e r a t e d . But t h i s does not provide us with a p r e d i c t i o n of d i s t r a c t i b i l i t y . One c h a r a c t e r i z a t i o n of Type A behavior which p r o v i d e s a p r e d i c t i o n of d i s t r a c t i b i l i t y , i n c o r p o r a t e s the Type A i n d i v i d u a l ' s tendency to engage i n p o l y p h a s i c behavior or simultaneous performance on m u l t i p l e tasks (Matthews, 1982; Dembroski, 1988). Because these i n d i v i d u a l s attempt to accomplish a l o t by simultaneously completing m u l t i p l e tasks and consuming the maximum amount of a v a i l a b l e i n f o r m a t i o n , t h i s may manifest i t s e l f i n poor performance on a t t e n t i o n r e l a t e d t a s k s . T h i s p e r s p e c t i v e suggests that Type A's should be h i g h l y P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 57 d i s t r a c t i b l e . T h i s a l s o i s c o n s i s t e n t with the idea that Type A's possess a wide beam of a t t e n t i o n with l a x and/or n o n - d i s c r i m i n a t i n g f i l t e r s . An opposing p r e d i c t i o n of performance on the d i s t r a c t i o n task i s based on Matthews and Brunson's (1979) f i n d i n g that Type A's and Type B's d i f f e r i n the way i n which they a l l o c a t e t h e i r a t t e n t i o n to t a s k s . In a dual task experiment, Type A's tended to focus t h e i r a t t e n t i o n on the tasks and events t h a t were portrayed as important or c e n t r a l (Stroop t e s t ) and to a c t i v e l y i n h i b i t t h e i r a t t e n t i o n to tasks and events portrayed as more p e r i p h e r a l ( a u d i t o r y s i g n a l r e a c t i o n - t i m e t e s t ) . T h i s f i n d i n g suggests t h a t Type A i n d i v i d u a l s are l e s s d i s t r a c t i b l e than Type B i n d i v i d u a l s . T h i s r e s u l t i s based on the assumption that the dual task assesses the same a b i l i t y as the d i s t r a c t i o n task. An important c r i t e r i o n of Type A behavior which can n u l l i f y any performance p r e d i c t i o n s i s t h a t the Type A behavior may o n l y be e l i c i t e d from s u s c e p t i b l e i n d i v i d u a l s by an a p p r o p r i a t e l y c h a l l e n g i n g environment (Matthew, 1982). Studies have demonstrated the importance of p e r c e i v e d c h a l l e n g e as w e l l as p e r c e i v e d c o n t r o l i n t r i g g e r i n g the Type A p a t t e r n of behavior. A study by Humphries, Carver & Neuman (1983) demonstrated such f i n d i n g s where s i g n i f i c a n t d i f f e r e n c e s i n performance on a c a t e g o r i z a t i o n task o n l y occurred i n c o n d i t i o n s perceived as moderately or h i g h l y c h a l l e n g i n g . Since no s i g n i f i c a n t d i f f e r e n c e i n performance i n the non-challenging s i t u a t i o n s occurred between Type A and Type B i n d i v i d u a l s , t h i s has s e r i o u s P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 58 i m p l i c a t i o n s f o r performance on the d i s t r a c t i o n task. I t i s p o s s i b l e t h a t the d i s t r a c t i o n task w i l l not be p e r c e i v e d as c h a l l e n g i n g enough to evoke the a t t e n t i o n a l d i f f e r e n c e s between Type A's and Type B's. N e v e r t h e l e s s , Type A s u b j e c t s are expected to t r y to master the d i s t r a c t i o n task more so than Type-B i n d i v i d u a l s . Whether t h i s e f f o r t i s expressed i n g r e a t e r accuracy, speed or d i s t r a c t i b i l i t y has yet to be determined. Method Subjects The 272 s u b j e c t s who completed the d i s t r a c t i o n task i n the f i r s t subexperiment served as s u b j e c t s i n t h i s subexperiment. Because of absenteeism between the time of completion of the d i s t r a c t i o n t e s t and the separate p e r s o n a l i t y i n v e n t o r i e s , s l i g h t l y d i f f e r e n t subsets of the o r i g i n a l 272 s u b j e c t s , were obtained f o r the d i f f e r e n t i n v e n t o r i e s . The number of s u b j e c t s who completed both the d i s t r a c t i o n t e s t and the i n v e n t o r y noted, i s as f o l l o w s : Eysenck P e r s o n a l i t y Inventory, 239; Sensation Seeking S c a l e , 163; Leyton Obsessional Inventory, 228; and Framingham Type A Inventory, 248. Apparatus and Procedure A l l the s t i m u l i and procedures were the same as i n the a r o u s a l subexperiment but with the a d d i t i o n of a s e r i e s of P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 59 p e r s o n a l i t y i n v e n t o r i e s which were completed w i t h i n seventeen weeks of the d i s t r a c t i o n t a s k . Persons f o r whom data were missi n g , were excluded from the a n a l y s i s p e r t a i n i n g to that dimension. Eysenck P e r s o n a l i t y Inventory (EPI) Subjects completed the Eysenck P e r s o n a l i t y Inventory (EPI) nine weeks a f t e r completing the d i s t r a c t i o n t a s k . The EPI measures p e r s o n a l i t y i n terms of two g l o b a l dimensions: e x t r a v e r s i o n / i n t r o v e r s i o n and n e u r o t i c i s m / s t a b i l i t y (Eysenck, 1971). According to Eysenck, the e x t r a v e r s i o n f a c t o r i s l i n k e d to the degree of e x c i t a t i o n and i n h i b i t i o n i n the C e n t r a l Nervous System, and the N e u r o t i c i s m f a c t o r i s l i n k e d to the " i n h e r i t e d degree of l a b i l i t y " or s t a b i l i t y of the nervous system (1971). The EPI i s a 57-item t e s t . I t has been c r o s s - v a l i d a t e d a g a i n s t Lanyon's C a l i f o r n i a P s y c h o l o g i c a l Inventory (1974), the G u i l f o r d E x t r a v e r s i o n Scale (1940), and a number of other p e r s o n a l i t y i n v e n t o r i e s (Eysenck, 1971). The EPI appears i n Appendix G. S e nsation Seek inq Scale(SSS) Subjects completed form V of the Sensation Seeking Scale (SSS) (Zuckerman, Eysenck & Eysenck, 1978) seventeen weeks a f t e r completing the d i s t r a c t i o n task. The SSS measures s u b j e c t s ' tendency to seek and e x p l o r e r e l a t i v e l y novel and s t i m u l a t i n g s i t u a t i o n s . Form V c o n t a i n s 40 items and has been c r o s s - v a l i d a t e d a g a i n s t the longer form IV v e r s i o n (Zuckerman, 1979). Both forms of the SSS contains f i v e s u b s c ales which P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 60 i n c l u d e Experience Seeking, T h r i l l and Adventure Seeking, D i s i n h i b i t ion, Boredom S u s c e p t i b i l i t y , and General Sensation Seeking. C o r r e l a t i o n s between the Sensation Seeking Scale and such measures as the "Change Seeker Index" by G a r l i n g t o n and Shimona (1964); the E x t e r n a l Sensation s c a l e of the "Novelty E x p e r i e n c i n g S c a l e s " by Pearson (1970); the Harm Avoidance Subscale of the " P e r s o n a l i t y Research Form" ( n e g a t i v e l y r e l a t e d ) ; and the Risk s u b s c a l e of the "Eysenck I m p u l s i v i t y S c a l e " i n d i c a t e that they are measuring a s i m i l a r dimension. Most of these s c a l e s c o n t a i n items s i m i l a r to those i n the T h r i l l and Adventure Seeking s c a l e and consequently r e l a t e most h i g h l y to t h i s f a c t o r of the SSS (Zuckerman, 1979). The SSS s c a l e s i n g e n e r a l , and D i s i n h i b i t i o n i n p a r t i c u l a r , are r e l a t e d to the Eysenck dimensions of e x t r a v e r s i o n and n e u r o t i c i s m . Within the dimension of e x t r a v e r s i o n , the SSS r e l a t e s more s t r o n g l y to the i m p u l s i v i t y f a c t o r than to the s o c i a l i z a t i o n f a c t o r . C o r r e l a t i o n s with Murray Need Scale t e s t s and the 16PF t e s t (Zuckerman, 1979) suggest t h a t s e n s a t i o n seekers are e g o c e n t r i c a l l y e x t r a v e r t e d ; that i s , they are concerned with others as an audience or a source of s t i m u l a t i o n , r a t h e r than i n a dependent or n u r t u r a n t sense. Evidence a l s o i n d i c a t e s t h a t h i g h - s e n s a t i o n seekers tend to engage i n behavior t h a t most persons appraise as moderately or h i g h l y r i s k y , whereas low-sensation seekers tend to avoid such s i t u a t i o n s . C o n s i s t e n t with t h i s f i n d i n g , s t u d i e s using v a r i o u s c o g n i t i v e and p e r c e p t u a l t e s t s suggest that s e n s a t i o n seeking i s P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 61 expressed i n an a c t i v e , complex, n o v e l t y - s e e k i n g approach i n the p r o c e s s i n g of i n f o r m a t i o n (Zuckerman and Link, 1968; Zuckerman et a l 1972). The SSS appears i n Appendix H. Obsessive/Compulsive Inventory The obsessive/compulsive behavior i n v e n t o r y completed by the s u b j e c t s f o u r t e e n weeks a f t e r completing the d i s t r a c t i o n t e s t , was a v a r i a n t of Leyton's Obsessional Inventory (Cooper & K e l l e h e r , 1973). This r e v i s e d v e r s i o n i s r e t i t l e d here as the "Behavior S t y l e Inventory" and i s based on a P r i n c i p a l Component A n a l y s i s of the o r i g i n a l Leyton Inventory. The scores on t h i s i n v e n t o r y are s i g n i f i c a n t l y c o r r e l a t e d with corresponding d a i l y o b s e s s i o n a l behavior. The i n v e n t o r y used here c o n t a i n s the f o l l o w i n g s u b s c a l e s , which were d e r i v e d from a p r i n c i p a l component a n a l y s i s of the items: D C o u n t i n g , Checking and R e p e t i t i o u s behaviors; 2)Clean & Tidy; 3) D i s s a t i s f a c t i o n and; 4)Incompleteness; 5)Methodical and C a r e f u l . The P r i n c i p a l Component A n a l y s i s shows that the most economical way of summarizing the o r i g i n a l Leyton r e p l i e s of normal s u b j e c t s i n v o l v e s only the f i r s t three components. The incompleteness and methodological components emerged i n a f a c t o r a n a l y s i s performed by Evans & Kazaran (1977). The Obsessive/Compulsive Behavior Inventory used i n t h i s study appears i n Appendix I. Framingham Type A Inventory The Type A behavior i n v e n t o r y was completed ten weeks a f t e r the d i s t r a c t i o n t e s t and was measured by the Framingham Type A Survey (Haynes, Levine, Scotch, F e i n l e i b & Kannel, 1978). P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 62 The Framingham Type A Inventory has been shown to be s i g n i f i c a n t l y c o r r e l a t e d with d a i l y s t r e s s , ambitiousness, t e n s i o n , emotional l a b i l i t y and anger (Haynes et a l ) . The p s y c h o s o c i a l s c a l e s d e r i v e d from the items i n c l u d e the f o l l o w i n g four c a t e g o r i e s : behavior types, s i t u a t i o n a l s t r e s s , somatic s t r a i n s and s o c i o c u l t u r a l m o b i l i t y . T h i s q u e s t i o n n a i r e has been shown to be c l o s e l y r e l a t e d to a n x i e t y , n e u r o t i c i s m and de p r e s s i o n . (Chesney et a l . , 1981). Although a re c e n t debate has developed over whether d i f f e r e n t surveys of Type A behavior p a t t e r n measure the same b e h a v i o r a l tendencies (Matthews, 1982) and the a b i l i t y f o r Type A s e l f - r e p o r t s to p r e d i c t coronary prone behavior (Linden, 1987), the i n v e n t o r y used here does assess i n d i v i d u a l s ' sense of time urgency, c o m p e t i t i v e d r i v e and p e r c e p t i o n of job p r e s s u r e . The Framingham Inventory c o n t a i n s 14 items which appear i n Appendix J . Re s u l t s and Discuss ion The f i n d i n g s of t h i s subexperiment which are presented i n Table 5, i n d i c a t e that e x t r a v e r s i o n , n e u r o t i c i s m and s e n s a t i o n seeking are not s i g n i f i c a n t l y c o r r e l a t e d with d i s t r a c t i b i l i t y which i s measured as a performance decrement under the c o n d i t i o n s of d i s t r a c t i o n . I n s e r t Table 5 Table 5 P e r s o n a l i t y and D i s t r a c t i b i l i t y Pearson C o r r e l a t i o n s E x t r a v e r s i o n EPI (n=239) Standardized  D i s t r a c t i b i l i t y Scores: V i s u a l A u d i t o r y General -.04 -.00 -.02 Neurot i c ism EPI (n=239) -.03 .06 .02 Sensation Seek ing (n=163) .10 .11 .12 Obsessive Type-A Compulsive Framingham (n=228) (n=248) Standard i z e d  D i s t r a c t i b i 1 i t y  Scores: V i s u a l .03 .04 A u d i t o r y .11* .17** General .09 .12* * P<.05 *•* P<.01 P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 63 Some of the other p e r s o n a l i t y measures that were admi n i s t e r e d , however, do demonstrate a l i n k with d i s t r a c t i b i l i t y . The c o r r e l a t i o n s shown i n Table 5 i n d i c a t e that Type A and obsessive/compulsive i n d i v i d u a l s tend to be more d i s t r a c t i b l e (at l e a s t to a u d i t o r y d i s t r a c t o r s ) . The l i n k between d i s t r a c t i b i l i t y and obsessive/compulsive behavior p a t t e r n s i s c o n s i s t e n t with Broadbent's (1986) and Gordon's (1985) v i s u a l s e arch f i n d i n g s where obsessive/compulsive i n d i v i d u a l s were more d i s t r a c t e d . These two s t u d i e s , even though they o n l y exposed s u b j e c t s to v i s u a l d i s t r a c t o r s , support the a u d i t o r y d i s t r a c t i o n r e s u l t s because e a r l i e r we demonstrated that d i s t r a c t i b i l i t y g e n e r a l i z e s across m o d a l i t i e s . ( R e c a l l the s i g n i f i c a n t l y p o s i t i v e c o r r e l a t i o n between v i s u a l and a u d i t o r y d i s t r a c t i b i l i t y . ) I t appears t h a t Wachtel's (1967) and Shapiro's (1965) c o n c e p t u a l i z a t i o n of obsessive/compulsive i n d i v i d u a l s as simply posessing a narrow a t t e n t i o n a l s p o t l i g h t i s not adequate to d e s c r i b e these r e s u l t s . However the a d d i t i o n of an u n c o n t r o l l a b l e or wide scanning component to t h i s s p o t l i g h t d e s c r i p t i o n (Gordon, 1985) can provide an adequate e x p l a n a t i o n as to why obsessive/compulsive i n d i v i d u a l s tend to be d i s t r a c t i b l e . According to t h i s d e s c r i p t i o n , an obsessive/compulsive i n d i v i d u a l i s unable to c o n t r o l the scanning width of t h e i r narrow a t t e n t i o n a l s p o t l i g h t . A s i m i l a r d e s c r i p t i o n of an a t t e n t i o n a l s p o t l i g h t might a p p l y to the Type A i n d i v i d u a l s who a l s o tended to be P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 64 d i s t r a c t i b l e . A l t e r n a t i v e l y , Type A i n d i v i d u a l s may possess a wide beam of a t t e n t i o n with a lax or n o n d i s c r i m i n a t i n g f i l t e r . Both of these d e s c r i p t i o n s are c o n s i s t e n t with the Type A's p o l y p h a s i c t e n d e n c i e s . This tendency to concentrate on more than one a c t i v i t y at a time could be m a n i f e s t i n g i t s e l f i n impaired performance under d i s t r a c t i n g c o n d i t i o n s . This view suggests that the Type A i n d i v i d u a l may be t r e a t i n g the d i s t r a c t o r s as w e l l as the matching task as two a c t i v i t i e s which must be processed or attended t o . According to t h i s i n t e r p r e t a t i o n , the Type A attends to the i r r e l e v a n t as w e l l as r e l e v a n t i n f o r m a t i o n i n an attempt to process a l l of the a v a i l a b l e i n f o r m a t i o n . In other words obs e s s i v e s and Type A's i n t h e i r e f f o r t s to be thorough are u n s u c c e s s f u l or slow i n sc r e e n i n g out i r r e l e v a n t i n f o r m a t i o n . T h i s use of excess i n f o r m a t i o n r e s u l t e d i n impaired performance. An a l t e r n a t e i n t e r p r e t a t i o n as to why Type A i n d i v i d u a l s tend to be d i s t r a c t i b l e i s suggested by Humphries et a l (1983) f i n d i n g s , t h a t the pe r c e i v e d importance of the d i s t r a c t i o n task u l t i m a t e l y i s r e s p o n s i b l e for e l i c i t i n g Type A behavior. One might p r e d i c t t h a t a c h a l l e n g i n g s e t t i n g would cause Type A's and p o s s i b l y o b s e s s i v e s to be l e s s d i s t r a c t e d . I t would not be s u r p r i s i n g i f obs e s s i v e s and type A's con s i d e r e d the d i s t r a c t i o n task to be unimportant r e l a t i v e to the monitoring of the d i s t r a c t i o n s t i m u l i i n the environment. The f i n d i n g s of t h i s subexperiment suggest that d i s t r a c t i b i l i t y i s p r e d i c t e d by some p e r s o n a l i t y dimensions. P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 65 While i t i s u n r e l a t e d to i n t r o v e r s i o n , e x t r a v e r s i o n , n e u r o t i c i s m and s e n s a t i o n seeking, d i s t r a c t i b i l i t y i s r e l a t e d to obsessive/compulsive and type A behavior. Hence Type A and obsessive/compulsive i n d i v i d u a l s are more apt to be d i s t r a c t i b l e . P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 66 Chapter 6 I n t e l l i g e n c e ; A P r e d i c t o r of D i s t r a c t i b i l i t y ? "When a high-IQ s u b j e c t has a w e l l - d e f i n e d task he most c l e a r l y shows what may p r o p e r l y be con s i d e r e d as h i s advantage a t the r a p i d sampling of r e l e v a n t i n f o r m a t i o n " (Eysenck, 1982 p.144). T h i s d e s c r i p t i o n of an i n t e l l i g e n t i n d i v i d u a l suggests t h a t the more i n t e l l i g e n t i n d i v i d u a l i s l e s s apt t o be d i s t r a c t e d by i r r e l e v a n t s t i m u l i . Eysenck views i n t e l l i g e n c e as a f u n c t i o n of a low l e v e l p e r c e p t u a l / a t t e n t i o n a l process as opposed to d e f i n i t i o n s based on higher l e v e l c o g n i t i v e p r o c e s s e s . The most common d e f i n i t i o n s of i n t e l l i g e n c e i n c l u d e the idea of b a s i c mental processes, higher-order t h i n k i n g , and the a b i l i t y to adapt to environmental change. Twenty-one percent of d e f i n i t i o n s i n 1921 and 1986 used b a s i c processes such as p e r c e p t i o n , s e n s a t i o n and a t t e n t i o n as a key a t t r i b u t e i n d e f i n i n g I n t e l l i g e n c e (Sternberg & Berg, 1986). These p e r c e p t u a l / a t t e n t i o n a l a t t r i b u t e s were the second most commonly used d e f i n i n g f e a t u r e of i n t e l l i g e n c e . T h i s i s a strong i n d i c a t i o n t h at p e r c e p t u a l / a t t e n t i o n a l processes c o n t r i b u t e a tremendous amount t o i n t e l l i g e n c e . P a r a d o x i c a l l y , recent e v a l u a t o r s such as Sternberg (1982), acknowledged a tremendous gap i n understanding t h i s p e r c e p t u a l / a t t e n t i o n a l c o n t r i b u t i o n to P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 67 i n t e l l i g e n c e . T h i s subexperiment i s a step i n the d i r e c t i o n of f i l l i n g i n t h i s gap and t e s t i n g the v a l i d i t y of p e r c e p t u a l / a t t e n t i o n a l d e s c r i p t i o n s of i n t e l l i g e n c e . The i n t u i t i v e l y a p p e a l i n g not i o n t h a t b r i g h t e r people pay a t t e n t i o n more e f f e c t i v e l y i s examined here. Sternberg (1982) and Hakstian and C a t t e l l (1976) suggest t h a t a t t e n t i o n or some other p e r c e p t u a l / a t t e n t i o n a l process i s r e s p o n s i b l e for i n t e l l i g e n c e . For i n s t a n c e , higher i n t e l l i g e n c e may be the product of g r e a t e r a t t e n t i o n a l f l e x i b i l i t y , more a t t e n t i o n a l r e s o u r c e s , more c a p a c i t y f o r p r o c e s s i n g i n f o r m a t i o n or greater c o g n i t i v e e f f i c i e n c y (Kahneman, 1973). One way to make such a connection between these a t t e n t i o n a l a b i l i t i e s and i n t e l l i g e n c e i n v o l v e s s t u d y i n g these a b i l i t i e s (e.g. i n t e l l i g e n c e and a t t e n t i o n a l c a p a c i t y , f l e x i b i l i t y , e f f i c i e n c y and p r e c i s i o n ) i n an i n d i v i d u a l d i f f e r e n c e study. With t h i s goal i n mind, experiments on d i c h o t i c l i s t e n i n g and a t t e n t i o n a l f l e x i b i l i t y were performed by Gopher & Kahneman (1971) and Kahneman, Be n l s h a i & Lotan (1973) on p i l o t s and bus d r i v e r s . These r e s e a r c h e r s found t h a t a r e l a t i o n s h i p e x i s t s between i n t e l l i g e n c e , psychomotor a b i l i t y and the a b i l i t y to s h i f t r a p i d l y or maintain a l r e a d y d i r e c t e d a t t e n t i o n i n response to an e x t e r n a l s i g n a l . There are a l s o s t u d i e s t h a t seem to show that d i f f e r e n c e s do e x i s t between i n d i v i d u a l s i n t h e i r a t t e n t i o n a l c a p a c i t i e s (Baron & Treisman, 1980; Hunt, 1980) and they seem to be r e l a t e d to d i f f e r e n c e s i n i n t e l l i g e n c e . In general i t appears th a t more able people have more a t t e n t i o n a l resources and thus P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 68 w i l l perform more competently when m u l t i p l e demands are placed on these r e s o u r c e s . The dual task method has been used to demonstrate t h i s r e l a t i o n s h i p (Norman & Bobrow, 1975; Posner, 1978; Hunt, 1980). One a d d i t i o n a l experimental s t r a t e g y f o r a s s e s s i n g the l i n k between a t t e n t i o n a l a b i l i t i e s and i n t e l l i g e n c e i n v o l v e s d i s c r i m i n a t i o n l e a r n i n g . D i s c r i m i n a t i o n l e a r n i n g i s conceived as having at l e a s t two important a s p e c t s , one p e r t a i n i n g to s e l e c t i v e a t t e n t i o n and the other with the l e a r n i n g of r e l a t i o n s h i p s between the products of a t t e n t i o n ( i e . c o r r e c t l y s e l e c t i n g a t a r g e t which co n t a i n s a combination of f e a t u r e s ) . S t u d i e s i n v o l v i n g d i s c r i m i n a t i o n between c o l o r s or forms have i l l u s t r a t e d the presence of these two components (Sternberg, 1982). In order to perform the task, s u b j e c t s are r e q u i r e d to s e l e c t the t a r g e t which contained a s p e c i f i c c o l o r and form. An example comes from the low end of the i n t e l l i g e n c e spectrum. Zeaman and House (1963) showed t h a t m e n t a l l y ret a r d e d i n d i v i d u a l s d i f f e r from normals more i n t h e i r having d i f f i c u l t y i n g i v i n g up i r r e l e v a n t i n favor of r e l e v a n t s t i m u l i then i n t h e i r speed of a s s o c i a t i n g c o r r e c t v a l u e s with rewards. This demonstrates t h a t s e l e c t i v e a t t e n t i o n might be r e s p o n s i b l e f o r impaired d i s c r i m i n a t i o n l e a r n i n g i n s u b j e c t s with extremely low i n t e l l i g e n c e . An a l t e r n a t e i n t e r p r e t a t i o n of these r e s u l t s i s t h a t low ^ i n t e l l i g e n t i n d i v i d u a l s may p e r s i s t i n responding on the b a s i s of an i n i t i a l l y p r e f e r r e d but a c t u a l l y i r r e l e v a n t s t i m u l u s dimension (Sternberg, 1982). The primary evidence from P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 69 t h i s r e s e a r c h for a l i n k between i n t e l l i g e n c e and d i s t r a c t i b i l i t y r e s t s i n the f i n d i n g t h a t the speed of l e a r n i n g to a t t e n d to r e l e v a n t dimensions i n c r e a s e s as a f u n c t i o n of i n t e l l i g e n c e (Zeaman & House, 1963, 1974). The i n t e n t of t h i s experiment i s to determine i f i n t e l l i g e n c e can p r e d i c t d i s t r a c t i b i l i t y . S e v e r a l measures of i n t e l l i g e n c e are assessed i n t h i s i n d i v i d u a l approach to s t u d y i n g d i s t r a c t i b i l i t y . These measures provide an i n d i c a t i o n of s u b j e c t s g e n e r a l i n t e l l i g e n c e which c o n s i s t s of both a c r y s t a l l i z e d and f l u i d component. C r y s t a l l i z e d i n t e l l i g e n c e encompasses the a b i l i t i e s t h a t are a c q u i r e d through l e a r n i n g (e.g. v e r b a l a b i l i t y ) . T h i s c o n t r a s t s with f l u i d i n t e l l i g e n c e which are the inborn c a p a c i t i e s used f o r problem s o l v i n g and reasoning i n novel s i t u a t i o n s . Because f l u i d and c r y s t a l l i z e d a b i l i t y tend to covary w i t h i n i n d i v i d u a l s (Sternberg, 1982), we may c o n s i d e r both to be a measure of g e n e r a l i n t e l l i g e n c e . The i n c l u s i o n of t e s t s which measure these components of g e n e r a l i z e d i n t e l l i g e n c e allows us to examine t h e i r r e l a t i o n s h i p to d i s t r a c t i b i l i t y . Method  Subjects The o r i g i n a l 272 s u b j e c t s who completed the d i s t r a c t i o n t e s t served as s u b j e c t s in t h i s subexperiment. Due to d i f f e r e n t i a l absenteeism the a c t u a l number of i n d i v i d u a l s t h a t P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 70 completed the v a r i o u s t e s t s were as f o l l o w s : Wonderlic Test, 251; Quick T e s t , 235 and S p e l l i n g Test, 248. Apparatus and Procedure In a d d i t i o n to the s t i m u l i and procedures used in the d i s t r a c t i o n and a r o u s a l subexperiments the s u b j e c t s were t e s t e d with i n v e n t o r i e s d e s c r i b e d below. These t e s t s were completed w i t h i n seven weeks of the d i s t r a c t i o n t a s k . The s e p a r a t i o n of t e s t days r e s u l t e d i n some data l o s s , as noted above. Persons f o r whom any data were missing were excluded from t h a t p a r t i c u l a r a n a l y s i s . Wonderlic Personnel Test Subjects completed Form IV of the Wonderlic Test (1977) seven weeks a f t e r completing the d i s t r a c t i o n t e s t . T h i s t e s t was designed f o r s e l e c t i n g among a p p l i c a n t s f o r employment i n business or i n d u s t r i a l s e t t i n g s . The Wonderlic Test measures c r y s t a l l i z e d and f l u i d i n t e l l i g e n c e . T h i s t e s t has been proven v a l i d as a measure of g e n e r a l i z e d i n t e l l i g e n c e i n a d d i t i o n to s u c c e s s f u l l y p r e d i c t i n g job performance a t most l e v e l s of employment. V a l i d i t y c o e f f i c i e n t s between mean and median t e s t scores and years of education range from .950 to .996 (Wonderlic, 1977). T h i s 50-item, 12 minute t e s t c o n t a i n s a n a l o g i e s , l o g i c problems, d e f i n i t i o n s , judgment qu e s t i o n s , s p a t i a l r e l a t i o n items and c l e r i c a l a b i l i t y q u e s t i o n s . Wonderlic (1977) argues that these items e s s e n t i a l l y measure an i n d i v i d u a l ' s a b i l i t y to l e a r n as w e l l as g e n e r a l mental a b i l i t y . Hence the Wonderlic p r o v i d e s us with a quick measure of general P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 71 mental and problem s o l v i n g a b i l i t y . The Wonderlic t e s t appears i n Appendix D. Quick Test Subjects completed the Ammons' Quick T e s t (1962), a p i c t u r e vocabulary t e s t , three weeks a f t e r completing the d i s t r a c t i o n t e s t . The Quick Test p r o v i d e s an untimed s c r e e n i n g of v e r b a l or c r y s t a l l i z e d i n t e l l i g e n c e . Subjects s e l e c t which of four p i c t u r e s best f i t s each of 35 words. T h i s t e s t was d e r i v e d from the f u l l Range P i c t u r e Vocabulary t e s t and has been v a l i d a t e d on 458 c h i l d r e n and a d u l t s . P u b l i s h e d data on the Quick Test suggest that i t shows both r e l i a b i l i t y and a high degree of c o r r e l a t i o n with the Wechsler Adult I n t e l l i g e n c e Scale (WAIS) (Wechsler, 1955; Mednick, 1969; O g i l i v i e , 1965 c i t e d i n Buros, 1972). The Pearson c o r r e l a t i o n between The Quick Test and the WAIS i s .80 (p<.001). There i s no s i g n i f i c a n t d i f f e r e n c e between mean Quick Test s c o r e s and the WAIS Ve r b a l Scale ( C u l l & C o l v i n , 1970). Mednick (1967) found the h i g h e s t c o r r e l a t i o n s between the Quick Test and Verbal i n t e l l i g e n c e as measured by the f o l l o w i n g t e s t s : Gates Reading Comprehension (r=.51), GATB-J-Verbal (r=.53), General Aptitude T e s t B a t t e r y (Part J ) : V o c a b u l a r y (r=.54) ( c i t e d i n Buros, 1972). Davis & Dizzone (1970) found that the Quick Test i s not onl y a v a l i d measure of i n t e l l i g e n c e , but i t i s a l s o very s t a b l e even with p o p u l a t i o n s whose i n t e l l i g e n c e t e s t performance i s o f t e n h i g h l y v a r i a b l e . Since the WAIS has been accepted as a v a l i d and r e l i a b l e assessment of ge n e r a l i n t e l l i g e n c e , the high c o r r e l a t i o n s with P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 72 the Quick Test suggests that i t too i s a v a l i d measure of g e n e r a l i n t e l l i g e n c e . The Quick-Test appears i n Appendix E. S p e l l i n q Component Assessment The S p e l l i n g Component Assessment which i s an updated and m o d i fied v e r s i o n of Simpson's d i a g n o s t i c word t e s t (1945), was completed by s u b j e c t s two weeks before performing the d i s t r a c t i o n t e s t . These t e s t s c o n t a i n the words most f r e q u e n t l y m i s s p e l l e d by c o l l e g e students (Simpson, 1945). Instead of s p e l l i n g e n t i r e words, the S p e l l i n g Component Assessment r e q u i r e s s u b j e c t s to s upply o n l y the most d i f f i c u l t p a r t s which are m i s s i n g . Each item c o n s i s t s of a word stem, and one or more blank s e c t i o n s . Each blank s e c t i o n may r e q u i r e from 1 to 5 l e t t e r s to complete the word (e.g. r e s t r a n t ) . Hints are provided i n ambiguous or p o t e n t i a l l y d i f f i c u l t cases (eg. obs ne/ not proper or c l e a n ) . The t e s t takes 10 minutes and c o n t a i n s 76 word items. T h i s f i l l - i n - t h e - w o r d s p e l l i n g t e s t c o r r e l a t e d .90 with Simpson's t r a d i t i o n a l d i c t a t i o n t e s t . S p e l l i n g t e s t s have been demonstrated to be s i g n i f i c a n t l y c o r r e l a t e d with school achievement i n E n g l i s h (r=.40) as w e l l as Math (r=.30), Chemistry (r=.40), B i o l o g y (r=.50), Science (r=.50), S o c i a l Studies (r=.50) and o v e r a l l average (r=.50) (Hakstian & C a t t e l l , 1976). These s i g n i f i c a n t c o r r e l a t i o n s suggest t h a t s p e l l i n g a b i l i t y i s a measure of c r y s t a l l i z e d i n t e l l i g e n c e and t h a t s p e l l i n g may be used as an i n d i r e c t measure of i n t e l l i g e n c e . Hakstian & C a t t e l l (1978) have found P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 73 t h a t s p e l l i n g a b i l i t y i s s i g n i f i c a n t l y c o r r e l a t e d with measures of p e r c e p t u a l speed and accuracy, f l u i d i n t e l l i g e n c e as w e l l as c r y s t a l l i z e d i n t e l l i g e n c e . The S p e l l i n g Component Assessment appears i n Appendix F. R e s u l t s & D i s c u s s i o n G e n e r a l i z e d P r o f i c i e n c y The g eneral p a t t e r n of f i n d i n g s of t h i s subexperiment i n d i c a t e that i n t e l l i g e n t people perform b e t t e r on the search task, i f we simply look at t h e i r raw performance i n terms of the number c o r r e c t . T h i s i s demonstrated i n Table 6 where a l l of the c o r r e l a t i o n s between the number c o r r e c t on the three s e c t i o n s of the d i s t r a c t i o n t e s t and the i n t e l l i g e n c e and s p e l l i n g s cores turned out p o s i t i v e and s i g n i f i c a n t . Since the number c o r r e c t on the d i s t r a c t i o n t e s t i s a measure of both speed and accuracy we may conclude that a d i r e c t r e l a t i o n s h i p e x i s t s between i n t e l l i g e n c e and performance speed and accuracy. The number c o r r e c t were s t a n d a r d i z e d across the three c o n d i t i o n s so as to c o n t r o l f o r p o t e n t i a l order e f f e c t s . Hence these f i n d i n g s suggest t h a t i n t e l l i g e n c e i s an e f f e c t i v e p r e d i c t o r of o v e r a l l performance on the d i s t r a c t i o n t a s k . I n s e r t Table 6 Looking at Table 7 we found, as might be expected, those who perform best on the c o n t r o l s e c t i o n of the d i s t r a c t i o n t e s t , a l s o do so on the v i s u a l and a u d i t o r y d i s t r a c t o r s e c t i o n s . Table 6 Standard i zed # C o r r e c t i n : C o n t r o l V i s u a l A u d i t o r y I n t e l l i g e n c e and Number C o r r e c t  Pearson C o r r e l a t i o n s Wonder1ic (n=251) .24 *** .29 *** .24 *** Quick (n=235) .12 * .14 ** .15 ** S p e l l i n g (n=248) .39 *** .42 *** .39 *** * p<.05 ** p<.01 ***p<.001 P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 74 This p r o f i c i e n c y a c r o s s s e c t i o n s was demonstrated i n the s i g n i f i c a n t c o r r e l a t i o n s among a l l three s e c t i o n s of the t e s t . People who were the l e a s t p r o f i c i e n t a t the task performed poorest whether d i s t r a c t o r s were present or not, as i n d i c a t e d by the p o s i t i v e c o r r e l a t i o n s between the number c o r r e c t s cores a c r o s s the three s e c t i o n s of the t e s t . I n s e r t Table 7 Although the n o t i o n t h a t "a b r i g h t mind i s a quick mind" (Hunt, 1980; Brand, 1981)) i s supported i n t h i s study by the s i g n i f i c a n t c o r r e l a t i o n s between i n t e l l i g e n c e and number c o r r e c t , t h i s t e l l s us l i t t l e about d i s t r a c t i b i l i t y . Table 8 pr o v i d e s the evidence f o r a l i n k between I n t e l l i g e n c e and d i s t r a c t i b i l i t y . In t h i s t a b l e we can see t h a t the Wonderlic, Quick and S p e l l i n g t e s t are s i g n i f i c a n t l y c o r r e l a t e d with at l e a s t two of the three d i s t r a c t i b i l i t y measures. Since the m a j o r i t y of the c o r r e l a t i o n s are h i g h l y s i g n i f i c a n t we can a t t r i b u t e some p r e d i c t i v e power to i n t e l l i g e n c e . O v e r a l l , there i s a s i g n i f i c a n t i n v e r s e r e l a t i o n s h i p between i n t e l l i g e n c e and d i s t r a c t i b i l i t y which i s r e f l e c t e d i n the negative c o r r e l a t i o n s between the i n t e l l i g e n c e and d i s t r a c t i b i l i t y s c o r e s . Hence i n d i v i d u a l s with low i n t e l l i g e n c e were found to be d i s t r a c t i b l e . The more i n t e l l i g e n t an i n d i v i d u a l i s , the more l i k e l y he i s to be low i n d i s t r a c t i b i l i t y and perform b e t t e r on d i s t r a c t i o n type of t e s t s . Table 8 In summary, the meaningful, d i r e c t i o n a l l y c o n s i s t e n t and 74a Table 7_ Gen e r a l i z e d p r o f i c i e n c y a c r o s s c o n d i t i o n s of the D i s t r a c t i o n Task Pearson C o r r e l a t i o n s on Standardized Scores #Correct i n : C o n t r o l V i s u a l A u d i t o r y # C o r r e c t i n C o n t r o l .86*** .87*** V i s u a l .86*** .88*** A u d i t o r y .87*** .88*** * P<.05 ** P<.01 *** p<.001 74b Table 8 I n t e l l i g e n c e and Standardized D i s t r a c t i b i l i t y Measures Pearson C o r r e l a t i o n s Wonderlic Quick-Test S p e l l i n g (n=251) (n=235) (n=248) V i s u a l D i s t r a c t - -.14* -.07 -.09 i b i 1 i t y A u d i t o r y D i s t r a c t - -.11 -.12* -.18* i b i 1 i t y General D i s t r a c t - -.15** -.11* -.16** i b i 1 i t y * P<.05 ** P<.01 P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 75 s i g n i f i c a n t c o r r e l a t i o n s found i n t h i s subexperiment, suggest t h a t a l i n k e x i s t s between i n t e l l i g e n c e and d i s t r a c t i b i l i t y . We can s a f e l y p r e d i c t t h a t a h i g h l y i n t e l l i g e n t i n d i v i d u a l w i l l be low i n d i s t r a c t i b i l i t y . P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 76 Chapter 7 C o n c l u s i o n : S u b j e c t i v e Impressions -vs- A c t u a l D i s t r a c t i b i l i t y T h i s study, which c o n s i s t e d of f i v e subexperiments, examined how e f f e c t i v e l y s u b j e c t i v e r e p o r t s , measures of a r o u s a l , i n t e l l i g e n c e and p e r s o n a l i t y p r e d i c t d i s t r a c t i b i l i t y . A number of expected and unexpected f a c t o r s emerged as v a l i d p r e d i c t o r s of d i s t r a c t i b i l i t y . As a n t i c i p a t e d , i n t e l l i g e n c e was found to be i n v e r s e l y r e l a t e d to d i s t r a c t a b i 1 i t y . Various p e r s o n a l i t y measures a l s o were found to p r e d i c t performance on the d i s t r a c t i o n t e s t . I n d i v i d u a l s who were high on obsessive/compulsiveness and Type A behavior p a t t e r n , tended to be more d i s t r a c t i b l e . Since o n l y i n t e l l i g e n c e and some p e r s o n a l i t y v a r i a b l e s p r e d i c t e d d i s t r a c t i b i l i t y , i t may be u s e f u l to ask which of two domains, i n t e l l i g e n c e or p e r s o n a l i t y , i s the best p r e d i c t o r of d i s t r a c t i b i l i t y . To do t h i s a m u l t i p l e r e g r e s s i o n was performed on the s t a t i s t i c a l l y s i g n i f i c a n t p e r s o n a l i t y and i n t e l l i g e n c e v a r i a b l e s p r i o r to s t a n d a r d i z a t i o n . The dependent measures of d i s t r a c t i b i l i t y ( v i s u a l , a u d i t o r y and general d i s t r a c t i b i l i t y taken s e p a r a t e l y ) were regressed on the seven independent p e r s o n a l i t y and c o g n i t i v e v a r i a b l e s . As can be seen i n Table 9, the Wonderlic Test (a measure of general i n t e l l i g e n c e ) accounted P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 77 for almost a l l of the v a r i a n c e i n p r e d i c t i n g v i s u a l and general d i s t r a c t i b i l i t y . I n s e r t Table 9 The m u l t i p l e r e g r e s s i o n f o r v i s u a l d i s t r a c t i b i l i t y was s i g n i f i c a n t with 4% of the v a r i a n c e i n d i s t r a c t i b i l i t y accounted fo r mainly by the Wonderlic t e s t . T h i s i s represented by the h i ghest Beta weight f o r the Wonderlic i n the r e g r e s s i o n equation which was p r e d i c t i n g v i s u a l d i s t r a c t i b i l i t y . (The beta weights r e f l e c t the r e l a t i v e c o n t r i b u t i o n of the v a r i a b l e s i n the r e g r e s s i o n equations t h a t are p r e d i c t i n g d i s t r a c t i b i l i t y . ) The A u d i t o r y D i s t r a c t i b i l i t y r e g r e s s i o n a l s o was s i g n i f i c a n t with 9% of the variance accounted f o r mainly by S p e l l i n g a b i l i t y and Obsessive-Compulsive behavior, which have the o n l y s i g n i f i c a n t Beta weights i n t h i s r e g r e s s i o n e q u a t i o n . The General D i s t r a c t i b i l i t y r e g r e s s i o n , l i k e the v i s u a l r e g r e s s i o n , was best p r e d i c t e d by the Wonderlic v a r i a b l e . T h i s r e g r e s s i o n was s i g n i f i c a n t and i t accounted f o r 7% of the v a r i a n c e on d i s t r a c t i b i l i t y . O v e r a l l p r e d i c t i v e s u p e r i o r i t y seems to occur fo r i n t e l l i g e n c e as r e f l e c t e d i n the s i g n i f i c a n t weightings on the Wonderlic and S p e l l i n g t e s t . ( R e c a l l from Chapter 6 the s t r o n g r e l a t i o n s h i p between i n t e l l i g e n c e and s p e l l i n g . ) The p r e d i c t i v e s u p e r i o r i t y of i n t e l l i g e n c e over p e r s o n a l i t y may be a t t r i b u t e d to the g r e a t e r inherent s t a b i l i t y of i n t e l l i g e n c e t e s t s . The i n t e r n a l c o n s i s t e n c y of these t e s t s which i s measured by s p l i t / h a l f r e l i a b i l i t y (or alpha chronbach) c o e f f i c i e n t , d i s p l a y such a t r e n d . For example, the mean Table 9_ M u l t i p l e Regression/Stepwise (n=107) V i s u a l D i s t r a c t i b i 1 i t y Beta Wonderlic -.22* Quick-Test -.06 Type A -.02 S p e l l i n g .02 Sensation Seeking -.02 Obsessive/Compulsive -.01 * P<.05 ** P<.01 R=.22, R* =.04, F(6,101)=5.5 p<.05 Au d i t o r y D i s t r a c t i b i l i t y Beta Wonderlic -.10 Quick-Test -.17 Framingham .02 S p e l l i n g -.30** Sensation Seeking -.16 Obsessive/Compulsive .22* R=.33, R* =.09, F(6,101)=6.6 p<.01 * P<.05 ** P<.01 General D i s t r a c t i b i l i t y Beta Wonderlic -.26* Quick-Test -.16 Framingham -.04 S p e l l i n g -.11 Sensation Seeking -.06 Obsessive/Compulsive -.07 R=.27, R* =.07, F(6,101)=8.5 p<.01 * P<.05 ** P<.01 P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 78 r e l i a b i l i t y c o e f f i c i e n t i s .83 f o r the EPI (Eysenck, 1971), .66 f o r the Framingham Type A Inventory (Houston & K e l l y , 1987) .78 for the Sensation Seeking Scale (Zuckerman, 1979) and .91 f o r the Wonderlic Personnel t e s t (1977). N e v e r t h e l e s s , s i g n i f i c a n t c o r r e l a t i o n s demonstrate that both p e r s o n a l i t y and i n t e l l i g e n c e do p r e d i c t d i s t r a c t i b i l i t y . In essence, a d i s t r a c t i b l e person can be c h a r a c t e r i z e d as one who i s l e s s i n t e l l i g e n t and tends toward Obsessive-Compulsive and Type A behavior. The r e s u l t s were not encouraging for s p e c i f i c measures of s t a t e and t r a i t a r o u s a l , e x t r a v e r s i o n , s e n s a t i o n seeking nor f o r s u b j e c t i v e r e p o r t s as p r e d i c t o r s of d i s t r a c t a b i l i t y . N o n s i g n i f i c a n t c o r r e l a t i o n s demonstrated t h a t these v a r i a b l e s were u n r e l a t e d to d i s t r a c t i b i l i t y . The vast amount of l i t e r a t u r e on e x t r a v e r s i o n , i n t r o v e r s i o n and a r o u s a l l e a d us to b e l i e v e that these p e r s o n a l i t y t r a i t s should a l s o p r e d i c t i n d i v i d u a l d i f f e r e n c e s i n d i s t r a c t i b i l i t y , however none of these turned out to be r e l a t e d to o b j e c t i v e measures of d i s t r a c t i b i l i t y . Assuming t h a t a r o u s a l l e v e l plays a r o l e i n e x t r a v e r s i o n , the n o n s i g n i f i c a n t c o r r e l a t i o n between e x t r a v e r s i o n and d i s t r a c t i b i l i t y r e i n f o r c e s the absence of a l i n k between a r o u s a l and d i s t r a c t i b i l i t y . Perhaps a more s t r e s s f u l or arousing s e t t i n g may have r e s u l t e d i n some r e l a t i o n s h i p between d i s t r a c t i b i l i t y and a r o u s a b i l i t y , e x t r a v e r s i o n or some of the other p e r s o n a l i t y measures; however no such r e l a t i o n s h i p was found here . P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 79 S u b j e c t i v e Impress ions of D i s t r a c t i b i l i t y The r e s u l t s that we r e p o r t e d i n Chapter 3 i n d i c a t e d t h a t people are unable to s u b j e c t i v e l y assess how d i s t r a c t i b l e they a r e . N e v e r t h e l e s s , some people c l e a r l y b e l i e v e t h a t they are d i s t r a c t i b l e . Although s u b j e c t i v e f e e l i n g s of d i s t r a c t i b i l i t y are not r e l a t e d to o b j e c t i v e indexes of performance decrement, i t may be i n t e r e s t i n g to see which i n d i v i d u a l d i f f e r e n c e v a r i a b l e s c h a r a c t e r i z e someone who f e e l s t h a t he or she i s e a s i l y d i s t r a c t i b l e . To do t h i s c o r r e l a t i o n s were performed between p e r s o n a l i t y and i n t e l l i g e n c e v a r i a b l e s and the items on the Stimulus S e l e c t i v i t y Inventory d e s c r i b e d i n Chapter 3. As you w i l l r e c a l l , t h i s i n v e n t o r y i s a c o l l e c t i o n of f a c e - v a l i d items t h a t assess how d i s t r a c t i b l e i n d i v i d u a l s b e l i e v e themselves to be. Table 10 c o n t a i n s the r e s u l t s of t h i s a n a l y s i s . As can be seen i n the t a b l e , n e u r o t i c i s m , Type A and Obsessive Compulsiveness are p o s i t i v e l y c o r r e l a t e d with s e l f - r e p o r t e d d i s t r a c t i b i l i t y . Therefore we can conclude t h a t i n d i v i d u a l s who are predisposed to n e u r o t i c i s m , Type A behavior and Obsessive Compulsiveness have a tendency to a l s o p e r c e i v e themselves as d i s t r a c t i b l e even though t h i s i s not n e c e s s a r i l y a t r u e r e f l e c t i o n of t h e i r performance i n r e a l l i f e . I n t e l l i g e n c e , e x t r a v e r s i o n and s e n s a t i o n seeking have no b e a r i n g on s e l f - p e r c e i v e d d i s t r a c t i b i l i t y . I n s e r t Table 10 We have a l r e a d y seen, however, t h a t p e r c e i v e d Table 10 Stimulus S e l e c t i v i t y Inventory and P e r s o n a l i t y Pearson C o r r e l a t i o n s St imulus S e l e c t i v i t y Inventory (Item composite) Type A .32 *** Obsessive Compulsive .32 *** N e u r o t i c i s m .49 *** E x t r a v e r s i o n -.04 Sensation Seeking* -.01 Wonderlic -.09 S p e l l i n g .04 Quick-Test -.04 *** p<.001 P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 80 d i s t r a c t i b i l i t y and measured d i s t r a c t i b i l i t y on our task are two d i s t i n c t phenomenon. Thus while i n d i v i d u a l s who p e r c e i v e themselves as d i s t r a c t i b l e are l i k e l y to be c h a r a c t e r i z e d as having n e u r o t i c , obsessive/compulsive and Type A b e h a v i o r a l t e n d e n c i e s , t h i s c o n t r a s t s with the p r o f i l e of i n d i v i d u a l s who are a c t u a l l y d i s t r a c t i b l e . Such d i s t r a c t i b l e i n d i v i d u a l s may be best c h a r a c t e r i z e d as l e s s i n t e l l i g e n t as w e l l as being Type A and obsessive/compulsive i n nature. This means t h a t Type A and obsessive/compulsive i n d i v i d u a l s both p e r c e i v e themselves to be, and a r e , d i s t r a c t i b l e , as c o n t r a s t e d with i n d i v i d u a l s v a r y i n g i n i n t e l l i g e n c e whose assessment of t h e i r own d i s t r a c t i b i l i t y i s independent of the a c t u a l s t a t e of a f f a i r s . Conclus ions T h i s t h e s i s has examined a number of i n d i v i d u a l d i f f e r e n c e s a s s o c i a t e d with d i s t r a c t i b i l i t y . The f o l l o w i n g f i n d i n g s which were obtained from the p revious s e t of subexperiments, allows us to make v a l i d p r e d i c t i o n s about the type of i n d i v i d u a l who i s d i s t r a c t i b l e : 1. ) The d i s t r a c t i o n t e s t developed here, t e s t s f o r an e x t r i n s i c form of d i s t r a c t i b i l i t y . By u t i l i z i n g such a t e s t , we have s p e c i f i c a l l y assessed the i n a b i l i t y to screen out s t i m u l i that are independent of the t a r g e t e d t a s k . 2. ) S e l f - r e p o r t i s an inadequate measure of p r e d i c t i n g d i s t r a c t i b i l i t y . 3. ) Although a r o u s a l p r e d i c t s o v e r a l l performance on the search component of the d i s t r a c t i o n t e s t , i t i s not u s e f u l as a P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 81 p r e d i c t o r of performance decrement under c o n d i t i o n s of d i s t r a c t i o n . 4. ) D i s t r a c t i b i l i t y i s p r e d i c t e d by the p e r s o n a l i t y dimensions of Type A and Obsessive/Compulsiveness. Those i n d i v i d u a l s who d i s p l a y these b e h a v i o r a l p a t t e r n s are more apt to be d i s t r a c t i b l e , and to a l s o p e r c e i v e themselves as being d i s t r a c t i b l e . 5. ) I n d i v i d u a l s who are high i n i n t e l l i g e n c e tend to be low i n d i s t r a c t i b i l i t y . In a d d i t i o n , i n t e l l i g e n c e , as a s i n g l e v a r i a b l e , i s the best o v e r a l l p r e d i c t o r of s u s c e p t i b i l i t y t o d i s t r a c t i o n . These f i n d i n g s c o n t r i b u t e to our understanding of what c o n s t i t u t e s a d i s t r a c t i b l e i n d i v i d u a l . The extent t o which d i s t r a c t i b i l i t y g e n e r a l i z e s a c r o s s tasks and other forms of a t t e n t i o n a l demands has yet to be uncovered by fut u r e r e s e a r c h . P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 82 References A l l p o r t , D.A., T i p p e r , S.P. & Chimel, N.R.J. (1985). P e r c e p t u a l i n t e g r a t i o n and p o s t - c a t e g o r i c a l f i l t e r i n g . In M.I. Posner & O.S.M. Marin ( E d s . ) , A t t e n t i o n and Performance; ( V o l . XI pp.107-132). H i l l s d a l e , NJ: Erlbaum. Ammons, R.B. & Ammons, C.H. (1962). The Quick Test (QT): P r o v i s i o n a l Manual, P s y c h o l o g i c a l Reports, 11, 111-161. Baron, J . & Treisman, R. (1980). Some problems i n the study of d i f f e r e n c e s i n c o g n i t i v e p r o c e s s e s . Memory and C o g n i t i o n , 8, 313-321. Bennet, G.K., Seashore, H.G. & Wesman, A.G. (1982). D i f f e r e n t i a l  A p t i t u d e T e s t s . New York: P s y c h o l o g i c a l C o r p o r a t i o n . Berlyne, D.E., O g i l v i e , J.C. & Parham, L.C. (1968). The d i m e n s i o n a l i t y of v i s u a l complexity, i n t e r e s t i n g n e s s , and p l e a s i n g n e s s . Canadian J o u r n a l of Psychology, 22 ( 5 ) , 376-387. Best, J.B.(1986). C o g n i t i v e Psychology New York: West P u b l i s h i n g Co. Borkovec, T.D. (1976). P h y s i o l o g i c a l and c o g n i t i v e processes i n the r e g u l a t i o n of a n x i e t y . In G.E. Schwartz, G.E. & D. Shapiro, (Eds.) Consciousness and s e l f - r e g u l a t i o n : Advances  i n r e s e a r c h : V o l . 1. Plenum P r e s s : New York, pp.261-312. P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 83 Borkovec, T.D. (1979). Pseudo ( e x p e r i e n t i a l ) - i n s o m n i a and i d i o p a t h i c ( o b j e c t i v e ) insomnia: T h e o r e t i c a l and t h e r a p e u t i c i s s u e s . In Eysenck, H.J. & Rachman, S. (Eds.), Advances i n behavior r e s e a r c h and therapy ( V o l . 2 pp. 27-55). London: Pergamon Press, 2, 27-55. Brand, C. (1981). General i n t e l l i g e n c e and mental speed: T h e i r r e l a t i o n s h i p and development. In M.P. Friedman J.P. Das & N. O'Connor (Eds.), I n t e l l i g e n c e and L e a r n i n g . New York: Plenum P r e s s . Broadbent, D.E. (1958). P e r c e p t i o n and Communication. New York: Pergamon Press. Broadbent, D.E. (1982). Task combination and s e l e c t i v e intake of in f o r m a t i o n . Acta P s y c h o l o g i a , 50, 253-290. Broadbent, D.E., Broadbent, M. and Jones, J.L. (1986). Performance c o r r e l a t e s of s e l f - r e p o r t e d c o g n i t i v e f a i l u r e and of o b s e s s i o n a l i t y . B r i t i s h J o u r n a l of C I i n i c a l Psychology, 25, 285-299. Broadbent, D.E., Cooper,P.F., F i t z e r a l d , P . & Parkos, K.R. (1982). The C o g n i t i v e F a i l u r e s Q u e s t i o n n a i r e (CFQ) & i t s c o r r e l a t e s . B r i t i s h J o u r n a l of C I i n i c a l Psychology, 21, 1-16 . Bru n i a , C.H.M. (1979). A c t i v a t i o n . In J.A. Michan, E.G.J. Eijkman & L.F.W. deKrerk (Eds.), Handbook of Psychonomics: ( V o l . 1 pp. 533-560). New York: N. Holland Press. B u l l e n , J.G. & Hemsley, D.R. (1984). P s y c h o t i c i s m and v i s u a l r e c o g n i t i o n t h r e s h o l d s . P e r s o n a l i t y and I n d i v i d u a l P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 84 D i f f e r e n c e s , 5, 735-739. Burnham, M.A., Pennebaker, J.W. & G l a s s , D.C. (1975). Time consciousness, achievement s t r i v i n g and the Type A coronary-prone behavior p a t t e r n . J o u r n a l of Abnormal Psychology, 84, 76-79. Buros, O.K. (1972). Mental Measurements Yearbook VI.. Highland Park, N.J.: Gryphon P r e s s . C a j a l , S.R. (1909). H i s t o l o q i e System, ( T e c h n i c a l R e p o r t s ) . Netherlands. Carver, C.S. & G l a s s , D.C. (1978). Coronary-prone behavior p a t t e r n and i n t e r p e r s o n a l a g g r e s s i o n . J o u r n a l of P e r s o n a l i t y  and S o c i a l Psychology, 36, 361-366. Chesney, M., Black, G., Chadwick, J . & Rosenman, R. (1981). P s y c h o l o g i c a l C o r r e l a t e s of the coronary prone behavior p a t t e r n . J o u r n a l of B e h a v i o r a l Medicine, 4, 217-230. Cooper, J . & K e l l e h e r , M. (1973). The Leyton Obsessional Inventory: A p r i n c i p a l component a n a l y s i s on normal s u b j e c t s . P s y c h o l o g i c a l Medicine, 3, 204-208. Contrada, R.J. & Krantz, D.S. (1988). S t r e s s , r e a c t i v i t y , and Type A behavior: Current s t a t u s and f u t u r e d i r e c t i o n s . Annals of B e h a v i o r a l Medicine, 10, 64-70. Coren, S. (1988). P r e d i c t i o n of insomnia from a r o u s a b i l i t y p r e d i s p o s i t i o n s c o r e s : Scale development and c r o s s v a l i d a t i o n , Behavior Research Therapy. Coren, S. & Hakstian, A.R. (1987). V i s u a l s c r e e n i n g without the use of t e c h n i c a l equipment: P r e l i m i n a r y development of a P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 85 b e h a v i o r a l l y v a l i d a t e d q u e s t i o n n a i r e . A p p l i e d O p t i c s , 26, 1468-1472. Coren S. & Hakstian, A.R. (1988). C o l o r v i s i o n s c r e e n i n g without the use of t e c h n i c a l equipment: Scale development and c r o s s - v a l i d a t i o n . P e r c e p t i o n & Psychophysics, 43, 115-120. Coren, S. & Porac, C. (1975). The myth of the normal eye: A methodological note. B u i l e t i n of the Psychonomic Soc i e t y , 5, 469-470. Coren, S., Porac, C. & Ward, L.M. (1984 ). Sensat ion and P e r c e p t i o n . New York: Academic P r e s s . C u l l , J.G. & C o l v i n , C.R. (1970). C o r r e l a t i o n between the Quick Test and WAIS Verbal Scale i n a r e h a b i l i t a t i o n s e t t i n g . Psychology Reports, 27(1) 105. Davidson, R.J. & Schwartz, G.E. (1976). The psychobiology of r e l a x a t i o n and r e l a t e d s t a t e s : a m u l t i - p r o c e s s theory. In D.E. Mostofsky, (Ed.), Behavior c o n t r o l and m o d i f i c a t i o n of phys i o l o g i c a l a c t i v i t y . Englewood C l i f f s , N.J.: P r e n t i c e - H a l l . . Davies, D.R., Jones, D.M. & T a y l o r , A. (1984). S e l e c t i v e and s u s t a i n e d a t t e n t i o n t a s k s : I n d i v i d u a l and group d i f f e r e n c e s . R. Parasuraman & D.R. Davies (Eds.), Var i e t i e s  of A t t e n t i o n (pp.63-69). New York: Academic Press. Davis, W.E. & Dizzone, D. (1970). R e l a t i o n s h i p between Quick t e s t and WAIS. P s y c h o l o g i c a l Reports. 26(2), 457. Dembroski, T.M. & Costa, P.T. (1988). Assessment of P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 86 coronary-prone behavior: A c u r r e n t overview. Annals of b e h a v i o r a l medicine, 10, 60-6 4. Deutsch, J.A. & Deutsch, D. (1963). A t t e n t i o n : Some t h e o r e t i c a l c o n s i d e r a t i o n s . P s y c h o l o g i c a l Review, 70, 51-61. Douglas, V . I . (1983). A t t e n t i o n a l and c o g n i t i v e problems. In M. Rutter (Ed.) B e h a v i o r a l Syndromes of B r a i n D ysfunction i n Childhood. New York: The G u i l f o r d P r e s s . Douglas, V.I. & Pe t e r s , K. G. (1979). Toward a c l e a r e r d e f i n i t i o n of the a t t e n t i o n a l d e f i c i t of Hyperactive c h i l d r e n . In G.A. Hale & M. Lewis (Eds.) A t t e n t i o n and C o g n i t i v e Development. New York: Plenum P r e s s . Duffy, E., (1959). The p s y c h o l o g i c a l s i g n i f i c a n c e of the concept of a r o u s a l and a c t i v a t i o n . P s y c h o l o g i c a l Review, 64, 265-275. Duffy, E. (1962). A c t i v a t i o n and Behavior. New York: Wiley. Easterbrook (1959 ). A c t i v a t i o n and Behavior. New York: John Wiley. Egeth, H.E., V i r g i , R.A. & Garbart, H. (1984). Searching f o r c o n j u n c t i v e l y d e f i n e d t a r g e t s . J o u r n a l of Exper imental  Psychology: Human P e r c e p t i o n &. Per f ormance . 10 (1) 32-39. E r i k s e n , C.W., Coles, M.G.H. M o r r i s , L.R. & O'Hara, W.P. (1985). An electromyographic examination of response c o m p e t i t i o n . B u l l e t i n of the Psychonomic S o c i e t y , 23, 165-168. E r i k s e n , B.A. and E r i k s e n , C.W. (1974). E f f e c t s of noise l e t t e r s upon the i d e n t i f i c a t i o n of a t a r g e t l e t t e r i n a nonsearch t a s k . P e r c e p t i o n and Psychophysics, 16, 143-149. P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 87 E r i k s e n , B.A. and S c h u l t z , D.W. (1979). Information p r o c e s s i n g i n v i s u a l search: A continuous flow conception and experimental r e s u l t s . P e r c e p t i o n and Psychophysics, 25, 249-263. Evans, D.R. & K a z a r i a n , S.S. (1977). The development of a s t a t e measure of obsessive compulsive behavior. J o u r n a l of C l i n i c a l Psychology, 33(2), 436. Eysenck, M.W. (1975). E x t r a v e r s i o n , a r o u s a l and speed of r e t r i e v a l from secondary s t o r a g e . J o u r n a l of P e r s o n a l i t y , 43(3), 390-401. Eysenck, M.W. (1982). A t t e n t i o n and A r o u s a l : C o g n i t i o n and Performance. New York: S p r i n g e r - V e r l i g . Eysenck, M.W. (1986). A Handbook of C o g n i t i v e Psychology. H i l l s d a l e , NJ: Lawrence Erlbaum Ass., P u b l i s h e r s . Eysenck, H.J. (1967). The B i o l o g i c a l B a s i s of P e r s o n a l i t y . S p r i n g f i e l d , I l l i n o i s : Thomas. Eysenck, H.J. (1971). E d u c a t i o n a l and I n d u s t r i a l T e s t i n g S e r v i c e Manual. San Diego, C a l i f o r n i a . Friedman, M. (1969). Pathogenesis of Coronary A r t e r y Disease. New York: McGraw H i l l . Friedman, M. & Rosenman, R. (1974). Type A Behavior and your Heart. New York: Knopf. G a t t i , S.W. & Egeth, H.E. F a i l u r e of s p a t i a l s e l e c t i v i t y i n v i s i o n . B u l l e t i n of Psychonomic S o c i e t y , 11, 181-184. G l a s s , D.C. (1977). Behavior P a t t e r n s , S t r e s s and Coronary  Disease. H i l l s d a l e , N.J.: Erlbaum. P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 88 G l a s s , G.V. & Hopkins, K.D. (1984). S t a t i s t i c a l Methods i n  Education and Psychology (V.2). New J e r s e y : P r e n t i c e H a l l . Goldbland, S. (1980). Stimulus s p e c i f i c i t y of p h y s i o l o g i c a l response to s t r e s s and the Type A coronary prone p e r s o n a l i t y . J o u r n a l of P e r s o n a l i t y and S o c i a l Psychology, 39, 670-679. Gopher, D. & Kahneman, D. (1971). I n d i v i d u a l d i f f e r e n c e s i n a t t e n t i o n and the p r e d i c t i o n of f l i g h t c r i t e r i a . P e r c e p t u a l  and Motor S k i l l s . 1335-1342. Gordon, P.K. (1985). A l l o c a t i o n of a t t e n t i o n i n o b s e s s i o n a l d i s o r d e r . B r i t i s h J o u r n a l of C I i n i c a l Psychology, 24, 101-107 . Gray, J.A. (1964b). Strength of the nervous system as a dimension of p e r s o n a l i t y i n man: A review of work from the l a b of B.M Teplov. In J.A. Gray (Ed.), Pavlov's Typology (pp. 157-287). London: Pergman P r e s s . Hakstian, A.R. & C a t t e l l , R.B. (1976). Manual f o r the Comprehensive A b i l i t y B a t t e r y (CAB). I l l i n o i s : I n s t i t u t e f o r P e r s o n a l i t y & A b i l i t y T e s t i n g . H akstian, A.R. & C a t t e l l , R.B. (1978). Higher stratum a b i l i t y s t r u c t u r e s on a b a s i s of twenty primary a b i l i t i e s . J o u r n a l of E d u c a t i o n Psychology, 70 (5) 657-669. H a r r i s , J.E. and W i l k i n s , A.J. (1982). Remembering to do t h i n g s : A t h e o r e t i c a l framework and an i l l u s t r a t i v e experiment. Human Le a r n i n g , 1, 123-136. Haynes, S.G., L e v i n e , S., Scotch, N. F e i n l e i b , M., Kannel, W.B. P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 89 (1978). The r e l a t i o n s h i p of p s y c h o s o c i a l f a c t o r s to CHD i n the Framingham Study, American J o u r n a l of Epidemiology, 107 (5), 362-402. Hebb, D.O. (1955). D r i v e s and the C.N.S. (Conceptual nervous system). Psychology Review, 62, 243-254. Herman, S., Blumenthal, J.A., Black, G.M., Chesney, M.A. (1981). S e l f - r a t i n g s of Type A (Coronary Prone) A d u l t s : Do Type A's know they are Type A's. Psychosomatic Medicine, 43 (5). Hernandez-Peon, R. (1966). In R.W. R u s s e l l (Ed.), F r o n t i e r s In  P h y s i o l o g i c a l Psychology (pp. 121-147). New York: Academic Press. Hockey, G.R.J. (1970). E f f e c t of loud noise on a t t e n t i o n a l s e l e c t i v i t y . Q u a r t e r l y J o u r n a l of Experimental Psychology, 22, 28-36. Houston, B.K. (1987). Type A Behavior i n housewives: R e l a t i o n to work, mental adjustment, s t r e s s , t e n s i o n , h e a l t h , fear of f a i l u r e and s e l f - e s t e e m . J o u r n a l of Psychosomat i c Research, 31(1), 55-61. Humpheries, C , Carver, S. & Neumann, P.G. (1983). C o g n i t i v e c h a r a c t e r i s t i c s of the Type A coronary-prone behavior p a t t e r n . J o u r n a l of P e r s o n a l i t y and S o c i a l Psychology. 44(1), 177-187. Hunt, E. (1980). I n t e l l i g e n c e as an i n f o r m a t i o n p r o c e s s i n g concept. J o u r n a l of Br i t i s h Psychology. 71, 449-474. James, W. (1950). The P r i n c i p l e s of Psychology. New York: Dover P u b l i c a t i o n s , ( O r i g i n a l work p u b l i s h e d 1890). P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 90 Kahneman, D. (1973). A t t e n t i o n and E f f o r t . Englewood C l i f f s , New J e r s e y : P r e n t i c e - H a l l Inc.. Kahneman, D., Ben-Ishai, R., & Lotan, M. (1973). R e l a t i o n of a t e s t of a t t e n t i o n to road a c c i d e n t s . J o u r n a l of A p p l i e d Psychology, 58, 113-115. Kahneman, D. & Henik R. (1981). P e r c e p t u a l o r g a n i z a t i o n and a t t e n t i o n . In M. Kubuoy & J.R. Pomerantz (Eds.), P e r c e p t u a l O r g a n i z a t i o n . H i l l s d a l e , New J e r s e y : Erlbaum. Kagan J . & Rosman B.L. (1964). C a r d i a c and r e s p i r a t o r y c o r r e l a t e s of a t t e n t i o n and an a n a l y t i c a t t i t u d e . J o u r n a l of Exper imental Chi Id Psychology, 1(1), 50-63. Keele, S.W., N e i l l , W.T. & de Lemos, S.M. (1978). I n d i v i d u a l P i f f e r e n c e s i n A t t e n t i o n a l F l e x i b i l i t y . A r l i n g t o n , Va.: O f f i c e of Naval Research, Personnel & T r a i n i n g Research Programs. Klove, H. (1987). A c t i v a t i o n , a r o u s a l and n e u r o p s y c h o l o g i c a l r e h a b i l i t a t i o n . J o u r n a l of C l i n i c a l and Experimental  Neuropsychology, 9, 297-309. K r y t e r K.D. (1985). The E f f e c t s of Noise On Man. Orlando, F l o r i d a : Academic P r e s s . Lacey, J . I . (1967). Somatic response p a t t e r n i n g and s t r e s s : Some r e v i s i o n of a c t i v a t i o n theory. P s y c h o l o g i c a l S t r e s s . New York: Appleton. Linden, W. (1987). On the impending death of the Type A c o n s t r u c t : Or i s there a phoenix r i s i n g from the ashes? Canadian J o u r n a l of B e h a v i o r a l Science, 19(2), 177-190. P r e d i c t i n g I n d i v i d u a l D i f f e r e n c e s i n D i s t r a c t i b i l i t y 91 Lynn, R. & Gordon, I.E. (1961). The r e l a t i o n of n e u r o t i c i s m and e x t r a v e r s i o n to i n t e l l i g e n c e and e d u c a t i o n a l attainment. B r i t i s h J o u r n a l of E d u c a t i o n a l Psychology, 31, 194-203. Malmo R.B.. (1959). A c t i v a t i o n : A n e u r o p s y c h o l o g i c a l dimension. P s y c h o l o g i c a l Review, 66, 367-386. Mandler, G. (1975a). Consciousness: Respectable, u s e f u l and prob a b l y necessary. In R. Solso (Ed.), Information  p r o c e s s i n g and c o g n i t i o n : The Loyo l a symposium. H i l l s d a l e , N.J.: Erlbaum. M a r t i n , M. & Jones, G.V. (1984). C o g n i t i v e f a i l u r e s i n everyday l i f e . In H a r r i s , J.E. and M o r r i s , P.E. (Eds.), Everyday  Memory and A c t i o n s and Absentmindedness. New York: Academic P r e s s . M a r t i n , V. & Venables S. (1980). Techniques i n P s y c h o p h y s i o l o g i c a l A c t i v i t y . New York: Academic Press. Matthews, K. (1982). P s y c h o l o g i c a l p e r s p e c t i v e s on the Type A behavior p a t t e r n . P s y c h o l o g i c a l B u l l e t i n , 91, 293-323. Matthews, K.A. & Brunson, B.I. (1979). A l l o c a t i o n of a t t e n t i o n and the Type A coronary-prone behavior p a t t e r n , J o u r n a l of P e r s o n a l i t y and S o c i a l Psychology, 37, 2081-2090. Mehrabian A. (1976) . Manual f o r the Qu e s t i o n n a i r e Measure of St imulus Screening and A r o u s a b i 1 i t y . Unpublished manuscript. UCLA, Los Angeles. Mehrabian A. & R u s s e l l , J.A.. (1973). A measure of a r o u s a l seeking tendency. Environment and Behavior, 5, 315-333. Mehrabian A. & R u s s e l l , J.A.. (1974b). An Approach to 92 Environmental Psychology, Cambridge, MA: MIT Press. Meldman, M.J. (1970). Diseases of A t t e n t i o n and Percept i o n . Oxford: Pergamon Press. Mehrabian, A. & West, S. (1977). Emotional impact of a task and i t s s e t t i n g on work performance of screeners and nonscreeners. P e r c e p t u a l Motor S k i l l s , 45, 895-909. N e i l l , (1977). I n h i b i t i o n and f a c i l i t a t i o n processes i n s e l e c t i v e a t t e n t i o n . J o u r n a l of Experimental Psychology: Human P e r c e p t i o n & Performance, 3, 444-4 50 N e i s s e r , U. (1967). C o g n i t i v e Psychology. New York: A p p l e t o n - C e n t u r y - C r o f t s . N i d e f f e r , R.M. (1976). Test of A t t e n t i o n a l and I n t e r p e r s o n a l S t y l e . J o u r n a l of P e r s o n a l i t y and S o c i a l Psychology. 34 (3), 394-404 N i s b e t t , R.E. & Wilson, T.D. (1977). T e l l i n g more than we can know: V e r b a l r e p o r t s on mental p r o c e s s e s . P s y c h o l o g i c a l Review, 84,231-258. Norman, D. & Bobrow, D. (1975). On data l i m i t e d and resource l i m i t e d p r o c e s s i n g . J o u r n a l of C o g n i t i v e Psychology,7, 44-60. Nowlis, V. (1965). Research with the mood a d j e c t i v e check l i s t . In S. Tompkins & C. Izard ( E d s . ) , A f f e c t : Measurement of  awareness and performance, New York: S p r i n g e r . Posner, M.I. (1978). Chronometric E x p l o r a t i o n s of the Mind. H i l l s d a l e , NJ: Erlbaum. Posner, M.I., Snyder, C.R., & Davidson, B.J. (1980). A t t e n t i o n 93 and the d e t e c t i o n of s i g n a l s . J o u r n a l of Experimental  Psychology; General, 109, 160-174. Pribram, K.H. (1975). A r o u s a l , a c t i v a t i o n and e f f o r t i n the c o n t r o l of a t t e n t i o n . P s y c h o l o g i c a l Review, 82, 116-149. Rachman, J.S. & Hodgson, R.J. (1980). Obsessions and Compuls ions. England c l i f f s , N.J.: P r e n t i c e - H a l l Inc.. R u s s e l l , J.A. (1979 ). A f f e c t i v e space i s b i p o l a r . J o u r n a l of P e r s o n a l i t y and S o c i a l Psychology, 37(3), 345-356. S c h i f f r i n , R.M. (1988). A t t e n t i o n . In R.C. Atkinson, R . J . H e r r n s t e i n , G. Lindzey & R.D. Luce, Steven's Handbook of Experimental Psychology V o l . 2_ (2nd Ed. ) . New York: John Wiley & Sons. Shapiro, D. (1965). N e u r o t i c S t y l e s . New York: Bas i c Books Inc.. S i d d l e , D.T. & Marigan, G. L. (1971). A r o u s a b i l i t y and i n d i v i d u a l d i f f e r e n c e s i n r e s i s t a n c e to d i s t r a c t i o n . J o u r n a l of Exper imental Research i n P e r s o n a l i t y , 5, 295-303. S i d d l e , D.T. (1971). The o r i e n t i n g response and d i s t r a c t i o n . A u s t r a l i a n J o u r n a l of Psychology. 23, 261-263. S i d d l e , D.A., M o r r i s h , R.B., White, K.D. & Mangan, G.L. (1969). R e l a t i o n of v i s u a l s e n s i t i v i t y to e x t r a v e r s i o n . Journa1 of Exper imental Research i n P e r s o n a l i t y , 3, 264-267. Simpson, R.G. (1945). A D i a g n o s t i c L i s t of S p e l l i n g Words for c o l l e g e Freshman. Journal of Education Psychology, 26, 366-373 . Sokolov, E.N. (1960). Neuronal models and the o r i e n t i n g r e f l e x . 94 In M.A. B r a z i e r (Ed.), The C e n t r a l Nervous System and  Behavior (pp. 187-276). T r a n s a c t i o n of the t h i r d c o nference: J o s i a h Macy J r . Foundation . Sokolov, E.N. (1969). The modeling p r o p e r t i e s of the nervous system. In M. Cole & I. Maltzman (E d s . ) , A Handbook of  Contemporary S o v i e t Psychology. New York: B a s i c Books. Stelmack, R.M. & Campbell, K.B. (1974). E x t r a v e r s i o n & a u d i t o r y s e n s i t i v i t y to high and low frequency. P e r c e p t u a l and Motor  S k i l l s , 38, 875-879. Stelmack, R.M., Achern, E. & Michaud, A. (1977). E x t r a v e r s i o n and i n d i v i d u a l d i f f e r e n c e s i n a u d i t o r y evoked responses. Psychophysiology, 14, 368-374. Sternberg, R.J. (1982). Handbook of Human I n t e l l i g e n c e . Cambridge: Cambridge U n i v e r s i t y P r e s s . Sternberg, R.J. & Berg, C.A.(1986). Q u a n t i t a t i v e i n t e g r a t i o n : D e f i n i t i o n s of i n t e l l i g e n c e : A Comparison of the 1921 and 1986 symposia. In Sternberg, R.J. & D e t t e r , D.K. ( E d s . ) , What i s I n t e l l i e n c e . Norwood, NJ: Ablex P u b l i s h i n g Corp. Stroop (1935). Studies of i n t e r f e r e n c e i n s e r i a l v e r b a l r e a c t i o n s . J o u r n a l of Experimental Psychology, 18, 643-662. Suedfeld, P. (1980). Restr i c t e d environmental s t imulat i on: Research and c l i n i c a l a p p l i c a t i o n s . Wiley: New York. Sverko, B. (1977). I n d i v i d u a l D i f f e r e n c e s i n time s h a r i n g performance. (Tech. Rep. ARL-77-4). Champaign-Urbana: U n i v e r s i t y of I l l i n o i s , A v i a t i o n Research Laboratory. Thayer, R.E. (1967). Measurement of a c t i v a t i o n through 95 s e l f - r e p o r t . P s y c h o l o g i c a l Reports, 20, 663-678. Thayer, R.E. (1970). A c t i v a t i o n s t a t e s as assessed by v e r b a l r e p o r t s and p h y s i o l o g i c a l v a r i a b l e s . Psychophysioloqy, 7, 86-94. Thayer, R.E. (1978). Factor a n a l y t i c and r e l i a b i l i t y s t u d i e s on the a c t i v a t i o n - d e a c t i v a t i o n check l i s t . P s y c h o l o g i c a l  Reports, 42, 747-756. Thompson, R. F. (1975). I n t r o d u c t i o n to P h y s i o l o g i c a l Psychology. New York: Harper & Row P u b l i s h e r s . T i p p e r , S.P. (1985). The negative priming e f f e c t : I n h i b i t o r y e f f e c t s of ignored primes. Q u a r t e r l y J o u r n a l of Exper imental  Psychology, 37A, 571-590. T i p p e r , S.P. & B a y l i s , G.C. (1987). I n d i v i d u a l d i f f e r e n c e s i n s e l e c t i v e a t t e n t i o n : The r e l a t i o n of pr i m i n g and interference to c o g n i t i v e f a i l u r e . P e r s o n a l i t y and I n d i v i d u a l D i f f e r e n c e s , 8, 667-675. Treisman, A.M. (1982). P e r c e p t u a l grouping and a t t e n t i o n i n v i s u a l s earch f o r fe a t u r e s and for o b j e c t s . J o u r n a l of  Exper imental Psychology: Human P e r c e p t i o n and Performance, 8(2) . 194-214. Treisman, A.M. (1969). S t r a t e g i e s and models of s e l e c t i v e a t t e n t i o n . P s y c h o l o g i c a l Review, 76 (3) 282-299. Treisman, A.M. (1964 ). S e l e c t i v e a t t e n t i o n i n man. Br i t i s h  M e d ical B u l l e t i n . 20, 12-16. Treisman, A. & Gelade, G. (1980). A f e a t u r e i n t e g r a t i o n theory of a t t e n t i o n . C o g n i t i v e Psychology, 12, 97-136. 96 Van Der Heuden, A.H.C. (1981). Short-term V i s u a l Information f o r g e t t i n g . London: Routledge & Kegan P a u l . Wachtel, P.L. (1967). Conceptions of broad and narrow a t t e n t i o n . P s y c h o l o g i c a l B u l l e t i n , 6, 417-429. Weschler, D. (1955). Manual f o r the Weschler Adult I n t e l l i g e n c e S c a l e . New York: P s y c h o l o g i c a l C o r p o r a t i o n . Wickens, C D . (1984). P r o c e s s i n g Resources i n A t t e n t i o n . In R. Parasurman & D.R. Davies (Eds.), V a r i e t i e s Of A t t e n t i o n (pp. 63-69). New York: Academic P r e s s . Witken, H.A. & Berry, J.W. (1975). P s y c h o l o g i c a l d i f f e r e n t i a t i o n i n c r o s s - c u l t u r a l p e r s p e c t i v e . J o u r n a l of Cross C u l t u r a l Psychology, 6,4-87. Wonderlic, E.F. (1977). Wonderlic Personnel Test Manual. N o r t h f i e l d , I l l i n o i s : E.F. Wonderlic & A s s o c i a t e s , Inc.. Yerkes, R.M. & Dodson, J.D. (1908). The r e l a t i o n of s t r e n g t h of s t i m u l u s t o r a p i d i t y of h a b i t - f o r m a t i o n . Journal of Comparative Neurology of Psychology, 18, 4 59-482. Zeaman, D. & House, B.J. (1963). The r o l e of a t t e n t i o n i n r e t a r d a t e d i s c r i m i n a t i o n l e a r n i n g . In N.R. E l l i s (Ed.) Handbook of mental d e f i c i e n c y . New York: MacGraw H i l l . Zeaman, D. & House, B.J. (1974). I n t e r p r e t a t i o n of Developmental tr e n d s i n d i s c r i m i n a t i v e t r a n s f e r e f f e c t s . In A.D. Pick (Ed.), Minnesota Symposia i n C h i l d Psychology ( V o l . 8). M i n n e a p o l i s : U n i v e r s i t y of Minnesota P r e s s . Zuckerman, M. (1972). P e r s o n a l i t y t r a i t s and experience c o r r e l a t e s of the SSS. J o u r n a l of Consult ing C l i n i c a l 97 Psychology, 39(2), 308. Zuckerman, M. (1979). Sensat ion Seek i n q : Beyond the Optimal  L e v e l of A r o u s a l . H i l l s d a l e , N.J.: Lawrence Erlbaum Assoc i a t e s . Zuckerman, M., Eysenck H.J.& Eysenck (1978). Sensation seeking i n England and America: Cross c u l t u r a l age and sex comparisons. J o u r n a l of C o n s u l t i n g C l i n i c a l Psychology, 32, 420-426. Zuckerman, M. & L i n k , B. (1968). Construct v a l i d i t y f o r the SSS. J o u r n a l of C o n s u l t i n g C l i n i c a l Psychology, 39, 308-4321. 98 Appendix A The D i s t r a c t i o n Test 99 Name or ID Sex SPEED & ACCURACY Instructions This is a test to see how quickly and accurately you can compare let t e r and number combinations. On the following pages are groups of these combinations. On the l e f t side of each l i n e you w i l l find a set of fi v e groups of numbers and/or l e t t e r s . One of these groups is underlined. The underlined group i s your "search target". On the right side of the page (separated by a dotted line) you w i l l find a similar set of combinations (in a d i f f e r e n t order). Your task i s to find the group which i s i d e n t i c a l to the underlined "target" combination and to simply run a l i n e through i t . The following examples have been marked c o r r e c t l y in the Answer column . Note that the combination marked must be exactly the same as the one that i s underlined in the test item. 1) ABD ACD ADB AEB AFB 2) BaA BaB BAB BaB BbA 3) A7B 7AB B7A 7BA AB7 Try these two examples for practice 4) BAa BaA BbA bBA BbB , BaA DBA BAa BbB BbA 5) 3AA 3B3 33A B33 BB3 B33 3AA 33A BB3 3B3 If you f i n i s h the items in Test A before time i s c a l l e d , check your work. Do not turn to Test B or C u n t i l you are told to do so. Remember that we are interested in how quickly you can do this task, so work as fast as you can. You w i l l have 3 minutes for each part of this t e s t . DO NOT TURN THE PAGE UNTIL YOU ARE TOLD TO DO SO. AFB AEB ^6 ACD ADB BaB B^A BAB BaB BaA ^EfA A7B AB7 7AB B7A T e s t A 1) dd4 d4b 4bd 4b4 ddb 2) 6v6 v44 44v 6v4 v46 3) L3x 3Lx XL 3 X3L 3xL 4) 312 zl3 z31 13z 3zl 5) bfm fbm mbf mfb frab 6) L3x 3Lx xL3 x3L 3xL 7) Aj8 jA8 J8A 8jA AjA 8) Y59 59Y 95Y 5Y9 Y95 9) lek elk kel kle ekl 10) cnA Acn CAn ncA Arte 11) mux mxu xmu uxra XUffl 12) emi mei iem eim iroe 13) h35 53h 5h3 3h5 35h 14) dlb bid lbd ldd ldb 15) ekl Ike kel lek kle 16) 69b 6b9 9b6 b6b b96 17) XXU UXS USX XSU .XUS 18) zfr rzf r f z fzr f r z 19) U4X X40 UX4 XU4 X4X 20) smn ssm msn mum rims 21) 17T 7IT TI7 1T7 7TI 22) 441 114 140 411 401 23) v z f v f f z f f zvf f vz 24) SRD DsR SRD DRs DSS d4b dd4 4bd ddb 4b4 6v4 v44 44v v46 6v6 3xL 3Lx L3x xL3 x3L zl3 13z 31z z31 3zl fmb mbf bfm mfb fbm 3xL L3x 3Lx xL3 x3L AjA J8A 8jA jA8 Aj8 59Y 95Y Y95 5Y9 Y59 elk ekl kle lek kel Anc cnA cAn Acn ncA uxm xum mux mxu xmu emi mei ime iem eim h35 5h3 3h5 53h 35h ldb lbd dlb bid ldd lek kel ekl kle Ike 69b b6b 6b9 b96 9b6 XXU USX XSU UXS XUS fz r f r z zfr r z f r f z D4X X4U UX4 X4X XU4 runs smn ssm mmn msn TI7 7IT 17T 1T7 7TI 441 401 140 114 411 vf f vzf zvf z f f f vz RsD DRs SRD DSR Dss 101 25) Rrr Rsr rqR ssr rrR Rsr rqR ssr 26) z x z ZXZ ZXX Xzx ZXZ zxX XZz ZXZ 27) rarA mAr mrr rmA rarA rmA Arm mrr 28) 338 A88 88A 88j jjA ........... 88j A88 jj A j j 8 29) L96 L69 6L9 69L L69 9L6 1.96 69L 30) mrf rmf fmr f rm mrf rmf fmr rfm 31) 4XU 4UX Uxx U4X X4X U4X 4XU 4UX 32) urns ussn suu smu usm smu urns suu 33) CPV PCV PVC VPC PCV CPV VCP PVC 34) RDB RBD BRD DRD RBD DBR BRD DRD 35) XXP XPU PPX PXU XPU XXP PPX PXU 36) HMM HSS SHH, SMM SHH SMM HSS HMM 37) auu UuA AUU UUA auu AUU aaU UuA 38) D8R R8D 8DR RD8 R8D D8R 8DR RD8 39) POC PCO OCP OPC POC OCP PCC OPC 40) PBD PDB DBP BPD DPB BPD PBD DBP 41) SYX SXY XYX XYS XYS SXY SYX XYX 42) PVC PCV VCP VPC VCP CPV PVC VPC 43) POC CCO OOC OPO PCO OOC POC OPO 44) SfS Ssf SFF sFf sFf SfS Sfs Ssf 45) GOQ GOq PPG pgO GOg OGp ppG pgO 46) MNn NNn MMn nunN mmN NNn MMn nNM 47) POo OpP OPO Pop POo Pop OpP OOq 48) PCc CPc PPc CcP PCC PPc CcP PCC 49) aA8 a8A 8A8 8aa 8aa 8A8 aA8 a8A 50) Sfs fSs SFs sFf SFf fSs fSF SFS 51) Dsd sdO dsd Dsd dsd qqs sdD 52) CS6 C66 6Sc c66 CS6 6Sc C66 53) 4cb lAb Ale 14b lAb 4cb AlC 54) Z83 ZC3 Z38 Z38 C53 ZC3 ZC8 55) a9d Ldb L9b a9d dL9 9dL L9b 56) L18 L81 L l l L81 1L8 L l l 81L 57) chc cho ohc ohc och oho chc 58) rzf rzr z r f rzf rzr zrf fzr 59) Arv Avr vrA Avr rAz Arv rvA 60) qpp pgg qgq qpp pgg qgq qgp 61) Anm mAn mnA Anm Amn mAn nmA 62) Uau Uua AUu Oaa uua AUu Uua 63) WNW wWN WWN WNw nWN WWN wNN 64) 4HM 4MH MH4 4MH MH4 HM4 HMH 65) Bbd BdB DbD DBB Bbd DdD DbD 66) Z83 833 Z38 833 Z38 83Z 383 67) qgj qjg iaa gqj qjg qgj jqp 68) tqf f t q f q t fqt f t q qtf tqf q f t 69) mrA rmA Amr mrA Amr rmA Arm 70) ddb bbd Ibb lbb ddb bbd dbb 71) 188 818 81A 818 81A 88A 188 72) XOU 00X UOX OOx OOX XOU XXU 73) Z85 C88 8C5 8Z5 8C5 C88 Z58 74) XL 9 09X U5L X9L U5L UL5 XL9 75) 7L7 717 1L7 1L7 171 7L7 717 76) RDB RBD BRD DRB RDB RBD BRD 103 77) 18L 81L L18 L81 81L L18 18L 811 78) Uuw Wwu wWu uwU Wwu wWu UWD Uuw 79) NNn NMn MMn Nmm MnN Nmm NNn MMn 80) d96 c69 69d 96d 69d c69 96c 96d 81) A4c 1AC IcA 14b IcA A4c 2bc lAc 82) HMH HSM SHH SMM HMH SMM MHS HSM 83) RRS DRD RDR DDS DRD DDS RDR RRS 84) CW W C VCC y z c WC VCC CCC VZC 85) 6RD 6DR RD6 R6D D6R 6DR R6D RD6 86) CKJ KJC JJC KKC CJK JJC KJC KKC 87) 2h4 h42 42h 4h4 42h 2h4 4h4 h24 88) YSX UYX OXY XYU UXY SXY UYX XYU 89) m3Z 3Zm 3zm 3m z Z3m 3Zm 3mz m3Z 90) rwo rro rwr owr rwo rwr owr rro 91) aro rao roa ora aro ora oar roa 92) mim eim emm imm imm mim mem eim 93) T i l ITT 11T TTt ITT 11T TTt TT l 94) ZXz ZXZ Zzx XXz ZXz zXz XZz XXz 95) 7Tt LTt tTt T i t L t t T i t tTt 7Tt 96) MSs Mss sSs sms sSs sms SMs MSS 97) GOg OOg ppg E 2 S L OOg OGg pgg ppg 98) wvu uvu uwv wwu vwu wwu uvu uwv 99) tht hft f f t fht f f t hft tht fht 100) ann man amn anm aara anm man ann STOP HERE — WAIT FOR FURTHER INSTRUCTIONS 104 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) 14) 15) 16) 17) 18) 19) 20) 21) 22) 23) 24) nvx bid aru vwu uwro 679 nra Test B nxv j L x n v vxn dlb ldb lbd bdl auc ura rau rua i i wvu xvn nvx xvn uvw vwv NAV COQ SCO N4H pRr 8Aa tLT VAV wura wmu mwu umw 769 967 697 976 rna anr arn nar j ^ ^ p mza amz azm maz AVN ANV VNA OCQ OQC CQO QOC UUS UCS 5X7 A97 520 oar c l c 31s cma H4N 4NH BN4 4HN pRP rpR PPr ^ X aA8 A8a a8A 8aA lTt U T T i t l t t aVv Vav aW vAA a4d 43c 34a 34c 5V9 7V5 5X9 A7b A79 A9b Ab7 250 0 2 5 ^ ^ 0 5 2 rao roa ora roo clo olc o c l lco 13s s31 3sl acm cca mca ante vxn nxv xnv bid bdl lbd aur rua rau 105 wvx wxv xvw dun dnu und udn l f k k f l lkf gpq gpq qpg gqp qu2 u2q J|| 2uq 441 410 140 rne ern enr lbd Ibb l i d BRD DRB RDB VMW WMV VWM DBO BDD BDO BPR RBP PRB bDb bDd bBd FFe eFF EEe ezE eZz EZz NZN NZz NzZ 97b 79b 79c 2b7 7b2| swv vwx fell 7c2 Sns 3sS Sns 3nS 052 025 205 cae ace eac h24 42h h42 4h2 ova avo ova r f a afr f r a mca acm craa cor roc rco ndu f k l k l f pqg q2u 2qu 411 114 nre rnr Idd Idb RBD BDR MVW MWV OBD ODB PBR BRP bDD dBd EFe EEf eZE EZe Nzn NZn 97c 79e 2d7 7d2 ^ Sn3 250 520 eca aec. 4h4 vao ava f r f arf arac cmc ocr ore 106 cho hoc hco och ohc rse sre esr ers aur ura rau rua gpg gqp qpg ann anm anm P93 199 9P3 ept tpe pte SXs A97 rna anr rrn arn . bid ^ ldb lbd . 81a 18a la8 ZHN ZNH NHZ BRB RBB BRP UCC USC SCC PRB BRP BBP CJC CKC CJK 11T T t l TTl sXs sxS xXs SXS .. l T t LtT 1T1 Ltt ... NzZ Nzn ZNz 41c 14d 41d S38 C83 C53 79b 9b7 1 I b79 . . 817 718 781 178 dbd bd4 4bd 64u 46u 464 hoc hco och ohc cho ers ser rse sre esr ura aur rau aru rua pqg |HSqgp gpg gqp asn an® tuna ann pgj S83 gpj i g p \im gjp jpg ept ete pte etp tpe arn nra anr rna rrn ldb bid lbb ldd lbd a81 81a 18a I^»al8 BHZ ZNH NZH NHZ BRP BBR RBB BRB BRR CUU^j^jUCC SCC USC BBP RPB A BRP PRB CJK CJC CKJ CKC T i l 1T1 11T T t l TTl sxS SXs sXs sXS xXs l T t L t t 1T1 LtT LTt NZn NzZ Nzn ZNz Zzn GQq Qgq QGq Gqg Gqq 41d 14d 41a 14c 41c S38 C53 C38 C83 97b A97 b79 9b7 79b 187 817 781 718 178 db4 d b d ^ ^ 4 b d bd4 u46 64u 464 u64 107 86] 87] 88] 89] 90! 9 i ! 92] 93] 94] 95] 96] 97; 98; 99; 100) i f k d69 aj8 796 enr v4X zvn RB8 COQ l k f k f l k l f 6d9 9d6 d96 VXX VXZ VZX a8j 8aj 3ja 769 767 969 rne ren ern 4Vv 4Vx nvz nzv R8B 8BR RBB CQO QCO OBD BDO DOB QOC OCQ .. ODB ZYX ZXY XYZ YZX c o o o c o u c o u o c OCc OOc cOO aA8 8aA a8A 8Aa zZe pBP Czz 3x7 37x 73x x73 l s 3 13s 31s r»dn ede enn n i f n f i nfn 3 5h h35 3h5 bdl l db b i d f k l • . ^ § \ > k i f k f l Ifk 96d .SS) d69 96d 6d9 d96 ZVX XVZ VXX VZX 2VX ja8 _ A«hsjL 8 a J 8ja a 8 j 797 ^ ... 767 769 797 nre j^fjP^S . ern e n r ( ^ ^ ) r n e V4x X4v . . t 5 l l ^ 4 V x X 4 v V 4 x znv vzn vzn nvz znv 8RB R8B RB8 CQO COQ QCO BOD ft OBD BOD DOB ODB YXZ • • . YXZ YZX ZXY U OCU UCO OCO COO OOc Occ cOO 8aA a8A 8aA Zze ZEe zEe zeZ bbB . czz . \ pb? bbB DBP zCC bPb pbP bpp CZZ Zee zCC STOP HERE -- WAIT FOR FURTHER INSTRUCTIONS czz CZZ 108 Test C 1) VYZ XVY VXY ZXY VYZ VZY ZXY VXY 2) b9c c69 69c 96b 69c 6cb 96b b9c 3) aou uoa oua auo oua aou auo uao 4) lc c c l o ole o c l lco c l o l c c o c l 5) X79 V97 V59 X95 V97 X95 V79 V59 6) Sc8 c8c 8sc cS8 cS8 Sc8 8sc c8S 7) otb bto obt tbo tbo otb obt bot 8) 5ed 3de 4de 2ed 2ed 3de 5sd 4de 9) red ede cdr rdc crd red rdc c^r 10) wst swt stw vtw wst swt wts vtw 11) uwm wum umu uwu umw uwm umu wum 12) qpp pqq EES ppg pqq ppq qpp ppg 13) xnv vnx nxn nvx vnx nxn xnv nvx 14) unu unm umn mnu umn unm mnu nmu 15) mzn mzz nzm nnz mzn mnz mzz nnz 16) Ypg ypg pyg pyg gyp ypg ygp 17) Y59 59Y 5Y9 Y95 5Y9 Y95 Y59 59Y .18) onu oun nou uno oun uno uon onu 19) udn und ndu dnu dun udn dnu und 20) 414 441 144 114 414 114 404 144 21) Rrp RPp pRr Ppr pRr RPp Rrp Ppr 22) TLT ITL ILT TLI LTI TLI TLT ILT 23) VMW VMV VWM WVM VWM VMW WMV VMV 24) WUu Wuu UWW WWU UWW WWU Wuu WUU 1 0 9 25) c3x 3xc xc3 cx3 3cx xc3 cx3 c3x 26) AVN VNA NNV NNA NVA VNA NNV NNA 27) yxx XXY YyX XyX YXX YyX XXY XyX 28) ELF FLE LFE LFL ELF FLE LFL ELE 29) MNV NMV VNM MVN MVN NMV MNV VNM 30) EEf E f f eFF FeF eFF FeF FFe EEf 31) CS8 C8S C8C 8SC CSC C8S S5C 8SC 32) hh6 6h8 h86 68h 68h hh6 h86 6h8 33) 34d 43c 34a 34c 34d 43a 34c 43c 34) 4Z4 4Z1 414 412 41Z 14Z 414 4Z1 35) QQo Qqo QOQ Qoq oQQ QQo QOQ Qoq 36) exc. cex ecx xce cxe ecx cex exc 37) aro rao roa or a oar aro roa ora 38) 8c6 8a7 87a 86c 87c 86c 8a 7 8c 6 39) use ues seu sue ues sue eus use 40) rwp wro wrw owr owr wrw rwo rwr 41) MUZ VUW vwu wvu uwv wur wvu vwu 42) ier e r i e i r r i e e i r i e r i r e r i e 43) 312 231 321 132 321 312 213 231 ,44) q2u 2gui qu2 uq2 2qu q2u u2q uq2 45) XYW vxw vwx wxv vxw svw wvx wxv 46) aet eta eae tae ate tae eta eae 47) SVI SIV SVI VSI IVS SVI SIV VSI 48) eth het ete teh eth het eht ete 49) mza are z zraa azm raaz mza amz zma 50) asx sax axs xsa asx sax axs xsa 51) VAv Wa VaV Wa AAV Wa VaV Wa 52) Wmw WWM WMw MMw WMw mWM wWM MMw 53) N4H H4N 4NH KN4 H4N 4NH HN4 4HN 5.4) dDd bDb dBd bBd bDD dDd bBd dBd 55) 3S8 S83 8S3 S38 S83 8S3 83S S38 56) 0X0 OOX OXX OVX OOX OXX OX0 XXO 57) CS8 SC8 S8C 8SC 8SC S8C SC8 S5C 58) 5X7 5V9 7V5 7X9 7X9 7V5 5V7 5X7 59) 7L7 1L1 717 71L 717 71L 7L7 1L1 60) RBD RDB DRB BRD BRD RBD RDB DRB 61) 181 818 718 781 818 718 181 178 62) wVv vWw WW ywV vWw Wvv vwV WW 63) nMin mMN mNN Mnn nmM Mnn nMm mNN 64) b96 c69 69c 969 69c c69 96c 969 65) 14c lac lea 14d lea 14c 12d lac 66) 2h4 h42 42h 42h 2h4 24h 224 67) XYZ XVY VXY XYV VXY ZXY XVY XYV 68) Sn3 sn3 3sn ns3 3ns Sn3 ns3 sn3 69) rwo wro orw rwo orw owr wro 70) aro rao roa ora aro ora oar roa 71) f n i f i f i f n i n f n f i i nf f n i n f i f i f 72) vwu wvu wvw vwv uwv vwv wvu wvw 73) the net eth eht eth het the eht 74) amra mna anm aran nan amn mna amm 75) 3x7 37x 73x x37 3x7 37x 73x x37 76) j8a a8j 8aj 8ja 8aj 8ja a8j j8a 77) 59Y 9Y5 5Y9 95Y Y95 59Y 78) f k l l k f k l f l f k f k l k f l 79) cm a acm cma mca acm amc 80) xnv vnx xvn xnv vnx vxn 81) rse srs ers rse srs sre 32) V4X 4VX 4VX 4VX VX4 XV 4 83) mzn nzz mzn nzz znn mnz 84) ILT ITL ITL ILT TLI TIL 85) 410 441 401 140 411 441 86) use ues use esu seu eus 87) PRB PBR RPB PRB BPR RBP 88) Rrp RPp Prr RPp pRr PPr 89) SXX sXX SXx SXX SXS SXX 90) nra nar nra arn arn anr 91) OUU OCU OUU OCU COU OUC 92) RBD RDB RDB BDR DRB BRD 93) OXX XXO XXO OXX XOO OXV 94) HNZ NHZ SHN HZN NBZ HNZ 95) VAV Vva VAV VaV VAA Vva 96) COQ CQO OCQ QCO COQ QOC 97) ZeE ZzE < ZEZ eZz ZeE ZzE 98) GQq GQg GQq QGg Qqq Qqg 99) nMm mm Mnn nMH mm nmM 100) 30° qQq qQo Qoq qQq oQQ STOP HERE ~ WAIT FOR FURTHER INSTRUCTIONS 112 Appendix B The Stimulus S e l e c t i v i t y Inventory Name or Student Id STIMULUS SELECTIVITY INVENTORY Instructions This questionnaire deals with a number of common perceptually related situations. For each question you should select the response which best describes you and your behaviours. You can select from among the following response alternatives} Never (or almost never) Seldom Occasionally Frequently Always (or almost always) A l l that you need to do is to c i r c le the f i r s t letter which corresponds to your choice. Thus i f the question were (X) Do you feel tired when you get up in the morning? H 8 0 F A and you are frequently t ired, you would simply indicate i t by c i rc l ing the letter F. To help you keep the responses in mind they'are l isted on the top of each page. TURN TO THE NEXT PAGE AND BEGIN 114 ANSWER CODE« For each question c i r c le the letter which corresponds to the f i r s t letter of your choice from Never Seldom Occasionally Frequently Always 1) It is easy for me to keep sights and sounds froa interfering with ay thoughts. N 8 0 F A 2) I find i t d i f f i c u l t to concentrate while a faucet is dripping. H 8 0 F A 3) Uneven shadows on the page of a book sake i t d i f f i c u l t to read. N 3 0 F A 4) I get confused trying to watch ac t iv i t ies such as a football game or c ircus where a number of things are happening at the same t ine. R S 0 F A 5) Noise from flourescent l ights impairs my a b i l i t y to read. N S 0 F A 6) The sound of intermittent t ra f f i c , disrupts ay ab i l i ty to concentrate. N S 0 F A 7) When in a car at night, I am often bothered by the oncoming headlights of other cars. N S 0 F A 8) I find that reflections of nearby leaps or l ights on the face of a TV screen Which I aa watching to be very distract ing. N S 0 F A 9) I aa a cala person. R S 0 F A 10) X aa easi ly distracted by conversations going on around a«. R S 0 F A 11) Z get flustered- i f I have several things to do at once. H S 0 F A 12) I aa good at rapidly scanning crowds and picking out a particular peron or face. R S 0 F A 13) I find i t d i f f i c u l t to study or l i s ten to something with people talking nearby. R S 0 F A 14) Having heard a sound, X often lay awake at night for some time. R S 0 F A 15) Fl ickering or flashing l ights seldom bother me. N S 0 F A 16) I am strongly affected by sudden loud noises. N S 0 F A 17) Sudden changes of any kind produce an immediate emotional effect on me. N S 0 F A 18) I am strongly affected by bright colors. N S 0 F A 1 115 ANSWER CODEi For each question c i rc le the letter which corresponds to the f i r s t letter of your choice froa Never Seldom Occasionally Frequently Always 19) When colors are faded or "off", on a color TV or f i lm, i t is annoying to me. R S 0 F A 20) Sometimes lights and sounds come at me so rapidly they confuse me. H S 0 F A 21) My attention is easi ly captured by things around me. H 8 0 F A 22) It seldom bothers me i f the record which I am listening to is scratched. N S 0 F A 23) I get excited eas i ly . N S 0 F A 24) When looking through a car windshield or window, I find spots or d irt distracting. N S 0 F A 25) I tend to remain excited or moved for a long period of time after seeing a good movie. N S 0 F A 26) The quality of the lighting in rooms has a strong effect on me. N 8 0 F A 27) Few places are quiet enough to allow me to fu l ly concentrate on d i f f i cu l t problems. N S 0 F A 28) Internal or personal thoughts frequently intrude on ay concentration. H 8 0 F A 29) - I .am good at picking a voice or instrument out of a piece of music that I am l istening to. N S 0 F A 30) I require a great deal of mental effort to maintain focused attention. N S 0 F A 31) I easily lose track of time when working at something. N 8 0 F A i 32) Strong emotions carry over for one or two hours after I leave the situation which caused them. R S 0 F A 33) I get caught up in my thoughts and become oblivious to what is going on around me. N S 0 F A 34) I am restless and fidgety. N S 0 F A 35) I startle easi ly. N 3 0 F A 36) I have no trouble reading or studying when thorp is noise or music around me. N S 0 F A 2 116 ANSWER CODEt For each question c i rc le the letter which corresponds to the f i r s t letter of your choice froa Never Seldoa Occasionally Frequently Always 19) When colors are faded or "off", on a color TV or f i l a , i t is annoying to ae. R 8 0 F A 20) Soaetiaes l ights and sounds coae at ae so rapidly they confuse ae. H 3 0 F A 21) My attention is easily captured by things around ae. R 8 0 F A 22) It seldom bothers me i f the record which I aa l istening to is scratched. R 8 0 F A 23) I get excited easi ly. R 8 0 F A 24) When looking through a car windshield or window, I find spots or dirt distracting. N S 0 F A 25) X tend to remain excited or moved for a long period of tiae after seeing a good movie. R 3 0 F A 26) The quality of the lighting in rooms has a strong effect on me. R 8 0 F A 27) Few places are quiet enough to allow ae to ful ly concentrate on d i f f i cu l t problems. R 8 O F A 28) Internal or personal thoughts frequently intrude on ay concentration. R 8 0 F A 29) X ,aa good at picking a voice or instruaent out of a piece of music that X aa listening to. R 8 0 F A 30) I require a great deal of aental effort to aaintain focused attention. R 8 O F A 31) I easily lose track of tiae when working at something. N 8 0 F A 32) Strong emotions carry over for one or two hours after I leave the situation which caused them. R S 0 F A 33) . X get caught up in my thoughts and become oblivious to what is going on around me. R S 0 F A 34) I am restless and fidgety. N S 0 F A 35) I startle easi ly. N S 0 P A 36) I have no trouble reading or studying when thorp is noise or music around me. N S 0 F A 2 117 ANSWER CODE: For each question c irc le the letter which corresponds to the f i r s t letter of your choice froa Never Seldom Occasionally Frequently Always 37) It is easy for me to ignore a bussing insect while studying. N 8 0 F A 38) I find i t d i f f i c u l t to carry on a conversation when the TV or radio is playing in the background. R S 0 F A 39) My mood is quickly influenced by entering new places. R 8 0 F A 40) with so much going on around me, i t ' s d i f f i c u l t for me to think about anything for any length of time. H 8 0 F A 41) When I read i t is easy to block out everything but the book. N S 0 F A 42) I find i t d i f f i c u l t to sleep i f there is a l ight on. N S 0 F A 43) I switch back and forth from task to task. N 8 0 F A 44) I find that my heart keeps beating fast for awhile after I have been 'st i rred up 4 . R 8 0 F A 45) I can be emotionally moved by what other people consider to be simple things; H 8 0 F A 46) Are you easily frustrated? R 8 0 F A 47) Scratches or dust on projected films and sl ides can often be distracting to me. H 8 0 F. A 48) It is easy for me to keep my mind on a single sight or sound. R S 0 F A 49) I tend to find vision uncomfortable in bright sunshine. R S 0 F A '50) I frequently find my mind wondering from the task at hand. N 8 0 F A 3 Appendix C Thayer S e l f - R e p o r t of A r o u s a l Name ; Sex Age instructions! Below you wi l l find a l i s t of words. Bach of the words describes feelings or mood. Please use the rating scale next to each word to describe, your feelings at this moment. You can select from among the following response alternatives! Definitely feel at this moment c i rc le D Moderately feel at this moment c i rc le M Slightly feel at this moment c i rc le S Definitely do not feel at this moment c i rc le N Example: If the item were relaxed D M S N and you feel s l ight ly relaxed at this moment, you would c i rc le S, i f you def in i te ly do not feel relaxed at this moment you would c i rc le Hj. and so forth. Work rapidly, but please mark a l l the words. Your f i r s t reaction is best. This should take only a minute or two. 1) active 0 II 8 N ID drowsy D M 8 N 2) placid D M 8 N 12) fearful D M 3 N 3) sleepy D M 8 N 13) l ive ly D M 8 N 4) j i t tery D M 8 N 14) s t i l l D M S N 5) energetic D M S N 15) wide-awake D M S N 6) intense D M S N 16) clutched-up D M s N 7) calm D M S N 17) quiet D M s N 8) tired D M S N 18) full-of-pep D M S N 9) vigorous D M S N 19) tense D M s N 10) at-rest D M S N 20) wakeful D M s N STOP HERE UNTIL INSTRUCTED TO GO ON 

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