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UBC Theses and Dissertations

Effects of background information and social modeling on judgments of pain in others Currie, Neil Alan 1979

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EFFECTS OF BACKGROUND INFORMATION AND SOCIAL MODELING ON JUDGMENTS OF PAIN IN OTHERS by NEIL ALAN CURRIE B.A., U n i v e r s i t y of A l b e r t a , 1977 A t h e s i s s u b m i t t e d i n p a r t i a l f u l f i l l m e n t of t h e r e q u i r e m e n t s for':the degree of Master of A r t s i n t h e F a c u l t y of Graduate S t u d i e s Department o f P s y c h o l o g y We a c c e p t t h i s t h e s i s as co n f o r m i n g t o t h e r e q u i r e d s t a n d a r d THE UNIVERSITY OF BRITISH COLUMBIA MAY, 1979 © N e i l A l a n C u r r i e , 1979 I n p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r an a d v a n c e d d e g r e e a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t t h e L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e a n d s t u d y . I f u r t h e r a g r e e t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by t h e Head o f my D e p a r t m e n t o r by h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . D e p a r t m e n t o f Psychology The U n i v e r s i t y o f B r i t i s h C o l u m b i a 2075 W e s b r o o k P l a c e V a n c o u v e r , C a n a d a V6T 1W5 June 16, 1979 i i ABSTRACT P s y c h o l o g i c a l r e s e a r c h on p a i n has h i g h l i g h t e d the apparent p l a s t i c i t y o f the e x p e r i e n c e and the s u b s t a n t i a l impact t h a t s o c i a l e v ents have as d e t e r m i n a n t s of i t s e x p r e s s i o n . F o r example, a w e a l t h of e v i d e n c e has demonstrated t h a t exposure to s o c i a l models d i s p l a y i n g r e l a t i v e t o l e r a n c e or i n t o l e r a n c e f o r p a i n f u l s t i m u l a t i o n i n d u c e s sub-j e c t s t o a l t e r v e r b a l r e p o r t s o f p a i n i n t o l e r a n t and i n t o l e r a n t d i r e c t -i o n s , r e s p e c t i v e l y . R e s e a r c h on t h e s e e f f e c t s , employing S i g n a l D e t e c t i o n Theory (SDT) methods, s u g g e s t s t h a t t h e s e e f f e c t s may be mediated by a l t e r a t i o n s i n s e n s i t i v i t y t o p a i n f u l s t i m u l i ( C r a i g & Coren, 1975; C r a i g & P r k a c h i n , 1978). A l t h o u g h the r e l e v a n c e of SDT methods t o d i a g n o s t i c d e c i s i o n - m a k i n g p r o c e s s e s has f r e q u e n t l y been p o i n t e d out, r e l a t i v e l y few s t u d i e s have em-p l o y e d SDT methods to i n v e s t i g a t e d i a g n o s t i c p r a c t i c e s . The SDT p e r s p e c t i v e on d i a g n o s t i c , p r o c e s s e s emphasizes the n o t i o n t h a t a p a r t i c u l a r d e c i s i o n r e g a r d i n g t h e p r e s e n c e and s e v e r i t y of symptoms r e f l e c t s the o p e r a t i o n of two F a c t o r s : 1) e v i d e n c e t h a t a p a r t i c u l a r phenomenon i s p r e s e n t i n the p a t i e n t , and 2) the d i a g n o s t i c i a n ' s r e a d i n e s s t o a c c e p t weak or s t r o n g e v i -dence as i n d i c a t i n g t h e p r e s e n c e of the i n f e r r e d phenomenon. I n p a i n e v a l u a t i o n s , v a r i a b l e s s uch as background i n f o r m a t i o n about the p a t i e n t a r e i m p o r t a n t i n d e t e r m i n i n g the d i a g n o s t i c i a n ' s c r i t e r i o n f o r a c c e p t i n g a p a r t i c u l a r s e t of e v i d e n c e as i n d i c a t i v e of p a i n . F o r t h e p a i n s u f f e r e r t h e d i a g n o s t i c i a n ' s c r i t e r i o n i s c r i t i c a l . A b i a s t o i n t e r -p r e t e x p r e s s i v e b e h a v i o r as i n d i c a t i v e t h a t l i t t l e p a i n i s p r e s e n t may i i i have d r a s t i c consequences on subsequent c a r e t a k i n g r e s p o n s e s . The p r e s e n t s t u d y was an attempt to e v a l u a t e the impact of a p r i o r i p a i n - r e l e v a n t i n f o r m a t i o n on o b s e r v e r s ' r e a d i n e s s to r e p o r t the o c c u r r e n c e of p a i n i n o t h e r s . A second f o c u s was to e v a l u a t e the i n f l u e n c e of exposure t o s o c i a l models on d i s c r i m i n a b i l i t y of the o v e r t b e h a v i o r of s u b j e c t s e x p e r i e n c i n g p a i n . SDT methods were employed f o r b o t h p u r p o s e s . V i d e o t a p e s t a k e n of s u b j e c t s exposed t o e l e c t r i c shocks of v a r y i n g i n t e n s i t i e s were p r e s e n t e d t o 30 o b s e r v e r s who attempted t o d e t e r m i n e the l e v e l of p a i n t h a t observed " s e n d e r s " were e x p e r i e n c i n g . A n a l y s e s of o b s e r v e r s ' judgments i n d i c a t e d t h a t o b s e r v e r s who were i n s t r u c t e d t h a t senders had had a p a i n - e n h a n c i n g t r e a t m e n t were b i a s e d toward r e p o r t i n g p a i n i n senders r e l a t i v e t o o b s e r v e r s i n s t r u c t e d t h a t senders had e x p e r i -enced a p a i n - r e d u c i n g t r e a t m e n t and r e l a t i v e t o c o n t r o l s . The b e h a v i o r of senders exposed t o a t o l e r a n t model was l e s s d i s c r i m i n a b l e and e l i c i t e d lower average p a i n r a t i n g s r e l a t i v e t o t h a t of senders exposed to an i n -t o l e r a n t model. A d d i t i o n a l f i n d i n g s were t h a t 1) males produced r e l i a b l y h i g h e r d i s c r i m i n a b i l i t y r a t i n g s t h a n females and 2) d i s c r i m i n a b i l i t y o f p a i n e x p r e s s i o n s was i n v e r s e l y r e l a t e d t o o b s e r v e r empathy. These r e s u l t s i n d i c a t e d t h a t : 1) judgments of the p r e s e n c e and s e v e r i t y of p a i n e x p e r i -enced by o t h e r s a r e s u b s t a n t i a l l y a f f e c t e d by background i n f o r m a t i o n , and 2) v a r i a t i o n s i n s o c i a l e x p e r i e n c e a r e c a p a b l e o f a l t e r i n g s u b j e c t s ' o v e r t e x p r e s s i o n s of p a i n . F i n d i n g s a r e d i s c u s s e d i n r e l a t i o n t o e x i s t i n g t h e o r i e s of s o c i a l i n f l u e n c e s on p a i n , and i n r e l a t i o n t o d i a g n o s t i c p r a c -i c e s i n t h e e v a l u a t i o n of p a i n i n the n a t u r a l s e t t i n g . i v TABLE OF CONTENTS Page No. ABSTRACT i i TABLE OF CONTENTS i v LIST OF FIGURES v LIST OF APPENDICES v i ACKNOWLEDGEMENTS v i i INTRODUCTION 1 METHOD 19 RESULTS 27 DISCUSSION 36 REFERENCES 51 APPENDIX A 57 APPENDIX B 58 V LIST OF FIGURES Page No. FIGURE 1. I n t e r a c t i o n between M o d e l i n g C o n d i t i o n and D i s c r i m i n a t i o n l e v e l on the measure of d i s -c r i m i n a t i o n (E) 30 FIGURE 2. Mean A (average p a i n r a t i n g ) v a l u e s as a f u n c t i o n o f s e n d e r ' s M o d e l i n g C o n d i t i o n and Shock I n t e n s i t y 32 v i LIST OF APPENDICES Page No. APPENDIX A. Consent Form 56 APPENDIX B. P o s t - S e s s i o n Q u e s t i o n n a i r e 57 v i i ACKNOWLEDGEMENTS I would l i k e t o thank the members of my t h e s i s committee f o r t h e i r s p e c i f i c s u g g e s t i o n s and f o r t h e i r s u p p o r t : D r s . Ken P r k a c h i n , Park D a v i d s o n , and Ray C o r t e e n . I owe my f r i e n d Ken P r k a c h i n s p e c i a l m e n t i o n f o r t h e months of good-humored and s c h o l a r l y e f f o r t he s p e n t , g u i d i n g t h i s r e s e a r c h . I would l i k e t o i s s u e s e p a r a t e thanks t o Dr. Ken C r a i g , t h r o u g h whose s u p p o r t t h i s s t u d y was made p o s s i b l e , and who has p r o v i d e d me w i t h r e s e a r c h e x p e r i e n c e throughout g r a d u a t e s c h o o l . Dr. L a r r y Ward h e l p e d me a v o i d some b l i n d a l l e y s e a r l y on w i t h h i s i n c i s i v e recommendations. Howard G r e e n s t e i n p r o v i d e d me w i t h encourage-ment t h a t s t i m u l a t e d r a p i d p r o g r e s s i n the i n i t i a l s t a g e s . Judy Hawkins and Pat Waldron typed t h e m a n u s c r i p t . F i n a l l y , s p e c i a l thanks to my w i f e Lyn f o r her u n f a i l i n g e m o t i o n a l s u p p o r t a t a l l times d u r i n g t h i s p r o j e c t . INTRODUCTION The p r e s e n t study was concerned w i t h e v a l u a t i n g the i n f l u e n c e of ..a v a r i e t y o f s o c i a l m a n i p u l a t i o n s on the d i s c r i m i n a b i l i t y o f d i s p l a y s o f p a i n , and b i a s e s i n d e c i s i o n s about t h e p r e s e n c e and magnitude o f p a i n . Two s p e c i f i c i s s u e s were o f major i n t e r e s t : (1) the impact o f e x p o s i n g s u b j e c t s e x p e r i e n c i n g p a i n t o v a r i a b l y t o l e r a n t s o c i a l models on the d i s c r i m i n a b i l i t y o f t h e i r o v e r t p a i n e x p r e s s i o n s , and (2) the e f f e c t s o f exposure t o p a i n - r e l e v a n t i n f o r m a t i o n on o b s e r v e r s ' judgments o f t h e mag-n i t u d e of p a i n e x p e r i e n c e d by o t h e r s . These i s s u e s were examined i n the co n t e x t o f an e x p e r i m e n t a l analogue o f c l i n i c a l p a i n - d i a g n o s i s s i t u a t i o n s S o c i a l i n f l u e n c e s on p a i n r e a c t i o n F o r d y c e (1976) has made a b a s i c d i s t i n c t i o n between o p e r a n t and r e -spondent p a i n b e h a v i o r . The concept o f respondent p a i n i s most a p p r o p r i -a t e l y a p p l i e d t o i n s t a n c e s of apparent p a i n t h a t r e s u l t from a c u t e i n j u r y or those t h a t a r e the d i r e c t consequence o f e f f e c t i v e tissue-damage. I f a p e r s o n i s bombarded by p e r i p h e r a l n o x i o u s s t i m u l a t i o n , respondent p a i n b e h a v i o r s a r e l i k e l y t o be e m i t t e d a u t o m a t i c a l l y . I n a d d i t i o n t o th e s e r e f l e x i v e components o f n o x i o u s s t i m u l a t i o n , F o r d y c e has proposed t h a t ep sodes o f apparent p a i n may a l s o have prominent o p e r a n t components, espe-c i a l l y i f such e p i s o d e s a r e p r o t r a c t e d . I n i n s t a n c e s i n v o l v i n g o p e r a n t p a i n , b e h a v i o u r i n d i c a t i v e o f p a i n may be shaped, m a i n t a i n e d o r o t h e r w i s e m o d i f i e d as a f u n c t i o n o f t h e s o c i a l consequences o f p a i n d i s p l a y s . T h i s a n a l y s i s o f e n v i r o n m e n t a l f a c t o r s t h a t modulate p a i n b e h a v i o r emphasizes t h a t e x p r e s s i o n s o f p a i n a r e f r e q u e n t l y i n s t r u m e n t a l i n the a c q u i s i t i o n o f s o c i a l r e i n f o r c e r s o r the t e r m i n a t i o n o f a v e r s i v e s o c i a l s i t u a t i o n s . P a i n b e h a v i o r s a r e s t r e n g t h e n e d i n the absence of r e i n f o r c e m e n t f o r , or,: 2 perhaps punishment o f , w e l l b e h a v i o r . T h i s p e r s p e c t i v e u n d e r l i n e s the f a c t t h a t e x p r e s s i o n s of p a i n have come t o be r e g a r d e d as i n t e r p e r s o n a l communi-c a t i o n s p a r t i a l l y under the c o n t r o l o f s o c i a l c o n t e x t u a l events ( C r a i g , 1978; C r a i g & P r k a c h i n , i n p r e s s ) , C r o s s C u l t u r a l E v i d e n c e A s u b s t a n t i a l body o f s y s t e m a t i c and a n e c d o t a l e v i d e n c e d e a l i n g w i t h c u l t u r a l i n f l u e n c e s on r e a c t i o n s to p a i n f u l events s u p p o r t s t h i s p e r s p e c -t i v e . I n a r e c e n t r e v i e w , Weisenberg (1977) i d e n t i f i e d d i f f e r e n c e s among s e v e r a l e t h n i c groups r e l a t e d t o r a t e of a d a p t a t i o n to and t o l e r a n c e of e l e c t r i c shock. T u r s k y and S t e r n b a c h (1967) i n a s t u d y examining r e a c t i o n s to the p a i n o f e l e c t r i c shock found s u b s t a n t i a l c o r r e s p o n d e n c e between autonomic measures and a t t i t u d e s toward p a i n . Yankees, d e f i n e d as P r o t e s -t a n t s of B r i t i s h d escent who e x p r e s s e d a p h l e g m a t i c , m a t t e r - o f - f a c t o r i e n -t a t i o n toward p a i n i n a p r i o r i n t e r v i e w showed the f a s t e s t r a t e of a d a p t a -t i o n t o e l e c t r i c shock o f d i p h a s i c palmar s k i n p o t e n t i a l s . I r i s h s u b j e c t s , d e s c r i b e d as i n h i b i t i n g t h e i r e x p r e s s i o n of s u f f e r i n g and c o n c e r n f o r p a i n , showed a lower palmar s k i n r e s i s t a n c e , a s s o c i a t e d w i t h the c o n s i d e r a b l e a n x i e t y which the I r i s h f e e l c o n s t r a i n e d not to v e r b a l i z e o r e x p r e s s o v e r t l y , as p r e d i c t e d from the p r i o r i n t e r v i e w . I t a l i a n s , c h a r a c t e r i z e d as e x p r e s -s i n g d e s i r e f o r r e l i e f from p a i n , e v i d e n c e d a p o s i t i v e c o r r e l a t i o n between upper p a i n t h r e s h o l d and h e a r t r a t e . Jews, d e s c r i b e d as e x p r e s s i n g c o n c e r n f o r the i m p l i c a t i o n of p a i n and d i s t r u s t i n g p a l l i a t i v e s , showed the o p p o s i t e . Those w i t h the h i g h e s t upper t h r e s h o l d f o r p a i n had the lowest h e a r t r a t e . In a s t u d y of b l a c k , w h i t e , and P u e r t o R i c a n d e n t a l p a t i e n t s (Weisenberg, K r e i n d l e r , Schachat, & Werboff, 1975) a t t i t u d i n a l d i f f e r e n c e s were o b t a i n e d r e f l e c t i n g r e l a t i v e w i l l i n g n e s s e i t h e r to deny o r to a v o i d 3 d e a l i n g w i t h p a i n , o r to get r i d o f t h e p a i n . T h i s was shown by r e s p o n s e t o such items as "The b e s t way to h a n d l e p a i n i s to i g n o r e i t " , " I t i s a s i g n of weakness t o g i v e i n to p a i n " , o r "When I am s i c k I want the d o c t o r to get r i d of the p a i n even b e f o r e he f i n d s out what the t r o u b l e i s " . P u e r t o R i c a n p a t i e n t s showed the s t r o n g e s t endorsement of t h e s e i t e m s , w h i t e s the weakest, b l a c k s i n between. In a c l i n i c a l s t u d y of w h i t e s , b l a c k s and o r i e n t a l s (Woodrow, Friedman S i e g e l a u b & C o l l e n , 1972) t o l e r a n c e of deep p a i n was measured. S u b j e c t s p l a c e d t h e h e e l of one f o o t on t h e f l o o r w i t h the a c h i l l e s tendon p o s i t i o n e d between two m o t o r - d r i v e n r o d s . Whites were found to t o l e r a t e the g r e a t e s t amount o f p a i n , o r i e n t a l s t h e l e a s t , and b l a c k s were i n between. Weisenberg (1977) reasoned t h a t such d i f f e r e n c e s i n s o c i o c u l t u r a l r e a c t i o n s to p a i n a r e d etermined i n p a r t by o b s e r v i n g the r e a c t i o n s to p a i n o f members of one's c u l t u r e . S o c i a l m o d e l i n g s t u d i e s P r k a c h i n (1978) has ..argued . t h a t , r e l a t i v e . t o l e r a n c e o r i n t o l e r a n c e of n oxious s t i m u l a t i o n may l a r g e l y be the p r o d u c t o f exposure to o t h e r s d i s -p l a y i n g r e l a t i v e t o l e r a n c e o r i n t o l e r a n c e of s i m i l a r s t i m u l a t i o n . One l i n e o f e v i d e n c e s u p p o r t i n g t h i s p o s i t i o n has come from s t u d i e s i n which the b e h a v i o r of companions has been m a n i p u l a t e d w h i l e s u b j e c t s a r e exposed to p a i n f u l s t i m u l a t i o n and w i l l i n g n e s s t o r e p o r t p a i n employed as the depend-ent measure. Exposure t o a model s i m u l a t i n g r e l a t i v e t o l e r a n c e f o r n o x i o u s s t i m u l a t i o n has been 1shown t o be e f f e c t i v e i n r e d u c i n g p a i n r e p o r t e d by s u b j e c t s u n d e r g o i n g r a d i a n t - h e a t s t i m u l a t i o n ( N e u f e l d & D a v i d s o n , 1971) and p r e s s u r e - i n d u c e d p a i n (Chaves & B a r b e r , 1974). 4 The impact of modeling processes on pain threshold and tolerance judgements has been demonstrated i n a series of laboratory studies. Craig and Weiss (1971) exposed undergraduate volunteers to s i x series of e l e c t r i c shocks gradually increasing i n intensity. Subjects rated each shock on a categorical judgment scale ranging from "undetectable" to "painf u l " . A confederate peer model who was ostensibly another subject undergoing the same procedure dissimulated either greater or lesser tolerance than the actual subject by making lower or higher ratings, or made ratings that were not contingent upon those of the subject. Subjects imitated the behavior of models i n the two active modeling conditions, with those exposed to a tolerant model accepting s i g n i f i c a n t l y greater current i n t e n s i t i e s before reporting pain than those exposed to an intolerant model. Subjects exposed to the noncontingent co-participant accepted intermediate l e v e l s . Similar results were obtained i n subsequent studies that employed a standard inten-s i t y of e l e c t r i c shock o r d i n a r i l y rated as non-painful by uninfluenced sub-j e c t s . Craig & Weiss (1972) and Craig, Best, & Reith (1974) reported that subjects exposed to an intolerant model rated the shock as painful 77% of the time while control subjects did so only 3% of the time. In a l a t e r study (Craig & Neidermayer, 1974) behavioral (pain threshold report) and psychophysiologic measures were employed i n a similar paradigm i n order to examine the degree of convergence of alternative measures of the response to noxious e l e c t r i c a l stimulation. As i n pr i o r studies, sub-jects exposed to tolerant models accepted substantially more shock than those interacting with no model or a control model, while those exposed to an intolerant model accepted substantially less. Measures of skin conduct-ance and heart rate, however, did not permit d i f f e r e n t i a t i o n of the groups. The authors concluded that to the extent that the physiological variables 5 r e f l e c t e d the b i o l o g i c a l p r o c e s s e s m e d i a t i n g the e x p e r i e n c e o f p a i n and d i s c o m f o r t , s u b j e c t s who were i n f l u e n c e d to a c c e p t v e r y h i g h l e v e l s of shock s u f f e r e d no more d i s t r e s s t h a n those who d e s c r i b e d the lower l e v e l s of shock as p a i n f u l . However, T u r s k y (1974) r e p o r t e d t h a t palmar s k i n conductance d a t a e x h i b i t c e i l i n g e f f e c t s a t low l e v e l s o f s t i m u l a t i o n , s u g g e s t i n g t h a t C r a i g & Neidermayer's f i n d i n g may have been a r t i f a c t u a l . T u r s k y noted f u r t h e r t h a t measures o f s k i n p o t e n t i a l e x h i b i t e d c l o s e c o r -respondence to l e v e l s of n o x i o u s s t i m u l a t i o n . In a l a t e r s t u d y , C r a i g & P r k a c h i n (1978) sought to overcome the d i f -f i c u l t i e s • i n t h e C r a i g and Neidermayer (1974) study by r e c o r d i n g s k i n p o t e n t i a l from f o r e a r m and abdominal s i t e s . S u b j e c t s exposed to e i t h e r a t o l e r a n t model o r an i n a c t i v e c o - p a r t i c i p a n t g e n e r a t e d n u m e r i c a l magnitude e s t i m a t e s to shocks p r e s e n t e d i n a s i n g l e a s c e n d i n g s e r i e s , and a s e r i e s o f r a n d o m l y - p r e s e n t e d shocks at f i v e s t a n d a r d i n t e n s i t i e s . S u b j e c t s ex-posed t o a t o l e r a n t model e x h i b i t e d s i g n i f i c a n t l y lower degrees of h e a r t -r a t e a c c e l e r a t i o n t o the c u r r e n t , and, u n l i k e c o n t r o l s u b j e c t s , the magni-tude of t h e i r f o r e a r m s k i n - p o t e n t i a l r e s p o n s e s h a b i t u a t e d over the c o u r s e of the random s e r i e s . As w e l l , the t o l e r a n t m odeling s o c i a l i n f l u e n c e s t r a -tegy reduced r e p o r t s of p e r s o n a l d i s t r e s s and d i m i n i s h e d s e n s o r y - d e c i s i o n t h e o r y measures of s e n s i t i v i t y t o n o x i o u s s t i m u l a t i o n . The a u t h o r s con-c l u d e d t h a t s o c i a l i n f l u e n c e t e c h n i q u e s p r o d u c i n g r e d u c t i o n s i n s e n s o r y s e n s i t i v i t y produce concomitant r e d u c t i o n s i n p h y s i o l o g i c a l a r o u s a l , r e f l e c t -i n g a m a n i p u l a t i o n o f fundamental c h a r a c t e r i s t i c s of p a i n f u l e x p e r i e n c e . I s s u e s i n the measurement o f p a i n r e s p o n s e s The use o f autonomic r e s p o n s e s as dependent measures i n the s t u d i e s by C r a i g & Neidermayer (1974) and C r a i g & P r k a c h i n (1978) r e f l e c t s r e c e n t c o n c e r n o v e r i n f e r e n t i a l d i f f i c u l t i e s i n v o l v e d w i t h a l t e r n a t i v e measures 6 of p a i n r e a c t i o n s . I t has been t r a d i t i o n a l i n e x p e r i m e n t a l s t u d i e s o f human p a i n r e a c t i o n s to use some form o f v e r b a l r e p o r t as an in d e x o f t h e o c c u r r e n c e o r magnitude o f p a i n (Beecher, 1959; C l a r k , 1969; H i l g a r d , 1969). T u r s k y (1974) f o l l o w i n g Beecher (1959) i d e n t i f i e d two components of i n d i v i d u a l s ' r e a c t i o n s t o p a i n . One i s a p s y c h o l o g i c a l o r r e a c t i v e component, a s e r i e s o f v e r b a l o r p h y s i c a l r e s p o n s e s which a r e p a r t l y i n -f l u e n c e d by v a r i o u s p s y c h o l o g i c a l , c u l t u r a l , and s i t u a t i o n a l f a c t o r s . The o t h e r i s the s e n s o r y or p e r c e p t u a l component, and has been d e s c r i b e d as the a c t u a l s e n s a t i o n o r h u r t t h a t the i n d i v i d u a l f e e l s . C l a r k (1969) has a r -gued t h a t many o f t h e d r a m a t i c e l e v a t i o n s i n p a i n t h r e s h o l d r e p o r t e d i n the l i t e r a t u r e r e f l e c t a r e s p o n s e b i a s t o sup p r e s s r e p o r t s o f p a i n r a t h e r than an a m e l i o r a t i o n o f the p a i n e x p e r i e n c e i t s e l f . I n terms o f T u r s k y ' s d i s t i n c t i o n , C l a r k ' s p o i n t i s t h a t a l t e r a t i o n s i n p a i n t h r e s h o l d o f t e n r e -f l e c t m a n i p u l a t i o n of the p s y c h o l o g i c a l - r e a c t i v e component i n s t e a d o f the s e n s o r y - p e r c e p t u a l component o f p a i n . I n an e f f o r t t o ^ i n v e s t i g a t e the l a t t e r component, r e s e a r c h e r s have t u r n e d to.two p s y c h o p h y s i c a l s t r a t e g i e s . The f i r s t has been t o employ S.S. S t e v e n s ' power law (Stevens, 1975) and n u m e r i c a l magnitude e s t i m a t i o n (ME) t a s k s . ME methods do not l i m i t an i n d i v i d u a l ' s assessment o f no x i o u s s t i m u l i t o a narrow range o f c a t e g o r i e s d e v i s e d by the exp e r i m e n t e r but a l l o w each p e r s o n to c o n s t r u c t as s e n s i t i v e and unique a s c a l e as i s r e -q u i r e d ( G r o s s b e r g & Grant, 1978). The r e s u l t a n t s c a l e r a t i n g s y i e l d a power f u n c t i o n e x p r e s s e d by the e q u a t i o n : y = K S n i n d i c a t i n g t h a t the p e r c e i v e d magnitude *F grows as the p h y s i c a l v a l u e of the s t i m u l u s S r a i s e d t o some power n. Thus the f u n c t i o n a l r e l a t i o n s h i p 7 between s t i m u l u s and r e s p o n s e i s d e s c r i b e d i n p r e c i s e l y q u a n t i f i a b l e terms. The second approach t o i n v e s t i g a t i o n of s e n s o r y p r o c e s s e s u n d e r l y i n g the e x p e r i e n c e of p a i n has been the use of s i g n a l - d e t e c t i o n t h e o r y (SDT) methods ( P a s t o r e & S h e i r e r , 1974). SDT methods have been employed i n o r d e r to t e a s e a p a r t two parameters of r e s p o n s e to noxious s t i m u l a t i o n : r e s p o n s e  b i a s and d i s c r i m i n a t i v e performance ( o f t e n termed " s e n s o r y s e n s i t i v i t y " ) . The a p p l i c a t i o n of SDT methods to the i n v e s t i g a t i o n of p a i n b e h a v i o r i s c u r r e n t l y an e x t r e m e l y a c t i v e a r e a of r e s e a r c h . I n a r e c e n t r e v i e w of SDT p a i n r e s e a r c h , Rollman (1977) l i s t s s t u d i e s employing a wide v a r i e t y of e x p e r i m e n t a l methods, and s uch d i v e r s e s o u r c e s of n o x i o u s s t i m u l a t i o n as r a d i a n t h e a t , e l e c t r i c a l s t i m u l a t i o n of t o o t h p u l p , and e l e c t r i c shock. Changes i n p a i n r e s p o n s e s produced by p l a c e b o s ( C l a r k , 1969), drugs (Chapman, Murphy & B u t l e r , 1973), s u b j e c t c h a r a c t e r i s t i c s ( C l a r k & Mehl, 1971), acu p u n c t u r e ( C l a r k & Yang, 1974), t r a n s c u t a n e o u s s t i m u l a t i o n ( B l o e d e l , E r i c k s o n , & McCreery, 1974) and s o c i a l i n f l u e n c e s ( C l a r k & Goodman, 1974). have been examined. As c o u l d be expected from such a d i v e r s i t y of i n d e p e n -dent v a r i a b l e s and methods, no s i m p l e o v e r a l l p a t t e r n o f r e s u l t s i s d i s -c e r n i b l e i n t h i s f i e l d . F o r the p r e s e n t d i s c u s s i o n i t i s s u f f i c i e n t to f o c u s a t t e n t i o n on the use o f SDT to examine s o c i a l i n f l u e n c e s on p a i n be-h a v i o r . SDT i n v e s t i g a t i o n s of s o c i a l i n f l u e n c e s on p a i n r e a c t i o n s SDT i n v e s t i g a t i o n s o f t h e e f f e c t o f an o r a l p l a c e b o ( d e s c r i b e d as a p o t e n t a n a l g e s i c ) on.isubj e c t r e s p o n s e s to r a d i a n t h e a t s t i m u l i i n d i c a t e d t h a t c r i t e r i o n f o r r e p o r t i n g p a i n was i n c r e a s e d w h i l e d i s c r i m i n a b i l i t y (d') was not a l t e r e d ( C l a r k , 1969; F e a t h e r , Chapman, and F i s h e r , 1972). 8 Both studies led to the conclusion that sensory e f f e c t s of the radiant heat s t i m u l i did not change as a function of exposure to analgesic sug-gestions, i n s p i t e of the f a c t that a l t e r a t i o n s were observed i n conven-t i o n a l indices of pain threshold. Clark & Goodman (1974) investigated the e f f e c t s of verbal suggestion on detection and tolerance thresholds for radiant heat s t i m u l i . Suggestion that subjects could t o l e r a t e more stimulation before reporting pain was e f f e c t i v e i n a l t e r i n g the p r o b a b i l i -ty of a pain response, but i t was without e f f e c t on subjects' a b i l i t y to discriminate noxious stimulation. Again, the authors concluded that there was no a l t e r a t i o n i n the amount of pain experienced by the subjects. SDT i n v e s t i g a t i o n s of s o c i a l modeling influences on pain reactions have provided evidence that exposure of subjects to tolerant or i n t o l e r a n t models i s associated with a l t e r a t i o n s i n s e n s i t i v i t y to noxious stimula-t i o n . In a study by Craig & Coren, (1975) using sub-pain threshold inten-s i t i e s of e l e c t r i c a l stimulation, exposure to an i n t o l e r a n t model was as-sociated with an increase i n a measure of sensory s e n s i t i v i t y , while expo-sure to a tolerant model had no e f f e c t on this index. To examine the im-pact of s o c i a l modeling at c l e a r l y noxious l e v e l s of stimulation, Craig & Ward (1976) employed supra-threshold l e v e l s of stimulation. Results i n d i -cated that exposure to a tolerant model was associated with reduced s e n s i -t i v i t y . However, these studies have been c r i t i c i z e d on a number of metho-do l o g i c a l grounds. The l e v e l s of stimulus i n t e n s i t y accepted by subjects varied among groups exposed to d i f f e r e n t models, thus confounding stimulus i n t e n s i t y with groups. In a d d i t i o n , i t has been pointed out that too few s t i m u l i were presented at each i n t e n s i t y to allow r e l i a b l e estimation of SDT parameters i n these studies (Rollman, 1977). A t h i r d problem was that only an o v e r a l l index of d i s c r i m i n a b i l i t y was calculated for each 9 s u b j e c t ; thus i t was i m p o s s i b l e t o t e l l whether o b s e r v e d m o d u l a t i o n s i n d i s c r i m i n a t i v e a b i l i t y o c c u r r e d a t h i g h shock i n t e n s i t i e s , low shock i n -t e n s i t i e s , or b o t h . C r a i g and P r k a c h i n (1978) r e - e v a l u a t e d m o d e l i n g i n f l u e n c e s i n a study t h a t overcame the g r o u p / s t i m u l u s l e v e l c o n f o u n d i n g by a d m i n i s t e r i n g s t a n d -a r d c u r r e n t i n t e n s i t i e s t o a t o l e r a n t m odeling group and a no-modeling group. S u b j e c t s i n t h e t o l e r a n t group e x h i b i t e d lower o v e r a l l a b i l i t y t o d i s c r i m i n a t e the shock, as i n the C r a i g & Ward s t u d y . However, the gener-a l i z a b i l i t y o f t h e s e r e s u l t s was weakened by the f a c t t h a t t h e r e was no c o n c l u s i v e measure t a k e n to show t h a t the s t i m u l a t i o n exceeded noxious l e v e l s f o r a l l s u b j e c t s . As i n t h e C r a i g & Ward stud y , a m b i g u i t y s t i l l e x i s t e d as to whether the m o d u l a t i o n i n d i s c r i m i n a b i l i t y o c c u r r e d a t h i g h o r low i n t e n s i t i e s or b o t h . A r e c e n t study ( P r k a c h i n , 1978) attempted to overcome the shortcomings of the p r i o r SDT a n a l y s e s of the e f f e c t of s o c i a l m o deling p r o c e d u r e s on p a i n . Both noxious and non-noxious s t i m u l u s i n t e n s i t i e s , de-f i n e d by s u b j e c t b e h a v i o r i n a preassessment s e s s i o n , were employed. A l l groups r e c e i v e d a s t a n d a r d s e r i e s of i n t e n s i t y l e v e l s and the number of p r e -s e n t a t i o n s a t each s t i m u l u s i n t e n s i t y was i n c r e a s e d to 54. The r e s u l t s of the experiment i n d i c a t e d t h a t i n t o l e r a n t m o d e l i n g was a s s o c i a t e d w i t h i n -c r e a s e d s e n s o r y s e n s i t i v i t y a t n o x i o u s l e v e l s o f s t i m u l a t i o n . T o l e r a n t m o d e l i n g was not a s s o c i a t e d w i t h d i f f e r e n t i a l v a l u e s of s e n s i t i v i t y , sug-g e s t i n g t h a t p r e v i o u s p o s i t i v e f i n d i n g s be q u a l i f i e d . To summarize, the i n v e s t i g a t i o n o f s o c i a l i n f l u e n c e s on p a i n r e a c t i o n has h i g h l i g h t e d the p l a s t i c i t y of the p a i n e x p e r i e n c e . L a b o r a t o r y s t u d i e s have demonstrated a l t e r e d p a i n r e a c t i o n as a f u n c t i o n of such p e r v a s i v e s o c i a l i n f l u e n c e as c u l t u r a l d e s c e n t , as w e l l as d i r e c t l y m a n i p u l a t e d i n -f l u e n c e i n the form of p l a c e b o s , v e r b a l s u g g e s t i o n , and c o n f e d e r a t e models. 10 A wide v a r i e t y o f dependent measures have been employed, v e r b a l r e p o r t s of p a i n f u l n e s s , w i l l i n g n e s s t o t o l e r a t e noxious s t i m u l a t i o n , as w e l l as p h y s i o l o g i c a l measures. S o p h i s t i c a t e d q u a n t i t a t i v e t o o l s have e v o l v e d (ME and SDT m e t h o d o l o g i e s ) a p p r o p r i a t e to the i n v e s t i g a t i o n of p a i n r e -a c t i o n , w h e r e i n the s o c i a l i n f l u e n c e s a r e b e i n g shown to e x e r t a complex impact. I m p l i c a t i o n s of the s o c i a l p e r s p e c t i v e , : r e s p o n s e s of o t h e r s to e v i d e n c e  o f p a i n I n s t u d i e s employing human s u b j e c t s the t y p i c a l r e s e a r c h approach has been to employ v e r b a l c h a r a c t e r i z a t i o n s of the e x p e r i e n c e of p a i n as the dependent v a r i a b l e . Other components of the r e s p o n s e to p a i n have been employed l e s s f r e q u e n t l y i f a t a l l . However, c u r r e n t c o n c e p t i o n s of the c o m p l e x i t y o f p a i n r e a c t i o n s and the v a r i a b l e s t h a t c o n t r o l them have be-gun to emphasize the importance of examining o t h e r components of the r e -sponse to p a i n ( L i e b e s k i n d & P a u l , 1977) . The s o c i o - b e h a v i o u r a l p e r s p e c t i v e on p a i n has i m p l i c a t e d i n t e r p e r s o n a l e v e n t s as c r i t i c a l v a r i a b l e s a f f e c t i n g p a i n r e a c t i o n s i n humans. S i n c e the b e h a v i o u r o f o t h e r s i n r e s p o n s e t o d i s p l a y s of p a i n i s of major s i g n i -f i c a n c e i n t h e s e a c c o u n t s , i t i s i m p o r t a n t to e v a l u a t e the r o l e of p a i n -m o d u l a t i o n s t r a t e g i e s i n i n f l u e n c i n g phenomena t h a t may e x e r t p o w e r f u l con-t r o l over the b e h a v i o u r o f o t h e r s . One major group of phenomena t h a t i n -f l u e n c e the b e h a v i o u r o f o t h e r s c o n s i s t s of o v e r t , n o n v o c a l d i s p l a y s of p a i n . F a c i a l e x p r e s s i o n s of f e a r , i n c l u d i n g w i n c i n g , grimaces and d i s -t o r t e d m u s cles, and p r o t e c t i v e b o d i l y movements, i n c l u d i n g guarded a c t i o n and movements, have c o n s i d e r a b l e meaning to o b s e r v e r s as i n f o r m a t i o n con-v e y i n g the p r e s e n c e and magnitude of p a i n ( C r a i g & P r k a c h i n , i n p r e s s ) . 11 Some i n d i c a t i o n o f the i m p o r t a n t r o l e t h a t e x p r e s s i v e b e h a v i o r p l a y s i n d e t e r m i n i n g e v a l u a t i o n o f e m o t i o n a l s t a t e s comes from r e s e a r c h i n the f i e l d o f " n o n v e r b a l communication". E v a l u a t i o n s of a v a r i e t y o f i n t e r n a l s t a t e s have been conducted, u s i n g n o n v e r b a l b e h a v i o r as dependent v a r i a b l e , f o r example i n r e s e a r c h on l y i n g ( K r a u t , 1978; Ekman & F r i e s e n , 1974), a n x i e t y (Waxer, 1977), p a i n ( P r k a c h i n , 1978), d e p r e s s i o n ( P r k a c h i n , C r a i g , " t.c. P a p a g e o r g i a , & R e i t h , 1977), and s o c i a l i n t e r p r e t a t i o n a c c u r a c y ( A r c h e r & A k e r t , 1977). I n r e s e a r c h on the p e r c e p t i o n of i n c o n s i s t e n t emotions, Mehrabian (1972) has c o n c l u d e d t h a t 55% of t h e t o t a l impact of an emotion i s a t t r i b u -t e d to f a c i a l c h a n n e l s . Other e s t i m a t e s as to the importance o f n o n v e r b a l i n f o r m a t i o n have been g e n e r a t e d . B i r d w h i s t e l l o f f e r s the "guess" t h a t "no more than 30 to 35% of the s o c i a l meaning o f an i n t e r a c t i o n i s c a r r i e d by the words" (1970, p. 197). Mehrabian's c o n c l u s i o n , however, i s based on the way i n which s i n g l e words a r e j u d g ed i n i s o l a t i o n , u s i n g posed, c o n t e x t -f r e e c o n t r a d i c t i o n s between v e r b a l and n o n - v e r b a l c h a n n e l s . The a r t i f i -c i a l i t y o f such a p r o c e d u r e i s apparent (Archer & A k e r t , 1977). E s t i m a t e s of the r e l a t i v e s t r e n g t h of v a r i o u s types o f e x p r e s s i v e cue v a r y w i d e l y , thus i n d i c a t i n g t h a t t h e f o r m u l a t i o n of a m a t h e m a t i c a l r e l a t i o n s h i p between cues and p e r c e i v e d meaning i s p r e s e n t l y premature ( A f g y l e , Alkema, & G i l m o u r f . 1971). A r c h e r & A k e r t (1977) e v a l u a t e d the r e l a t i v e c o n t r i b u t i o n s of v e r b a l cues v e r s u s f u l l - c h a n n e l ( v e r b a l - p l u s - n o n - v e r b a l ) cues to a c c u r a t e i n t e r p r e -t a t i o n o f a sequence of spontaneous s o c i a l b e h a v i o r . S u b j e c t s were exposed to a t h i r t y - m i n u t e a u d i o v i s u a l p r e s e n t a t i o n c o n s i s t i n g of 20 n a t u r a l s e -quences of b e h a v i o r , each 30 to 60 seconds i n l e n g t h , i n one of two 12 communication c o n d i t i o n s . One group of s u b j e c t s r e a d a w r i t t e n r e c o r d of t h e d i a l o g u e o f the v i d e o t a p e d scenes ( v e r b a l t r a n s c r i p t ) . The second group was exposed to the f u l l a u d i o v i s u a l p r e s e n t a t i o n ( f u l l c h a n n e l ) . The answers t o 20 m u l t i p l e c h o i c e q u e s t i o n s (one p e r scene) were s c o r e d a c c o r d i n g t o an unambiguous c r i t e r i o n o f a c c u r a c y (e.g., in:..one scene, two men d i s c u s s a game of b a s k e t b a l l they have j u s t p l a y e d , and the v i e w e r i s asked to d e c i d e which man won the game). F u l l - c h a n n e l s u b j e c t s averaged 8.85 c o r r e c t answers, v e r b a l t r a n s c r i p t s u b j e c t s 5.50, out of 20. T h i s d i f f e r e n c e was h i g h l y s i g n i f i c a n t (p.<.001). Both samples d i f f e r e d s i g n i f i c a n t l y from the chance a c c u r a c y l e v e l , but the t r a n s c r i p t sample performed s i g n i f i c a n t l y below chance w h i l e t h e i f u l l -c h a n n e l sample performed s i g n i f i c a n t l y above chance. The a u t h o r s c o n c l u d e d t h a t p u r e l y v e r b a l i n f o r m a t i o n about i n t e r a c t i o n s makes no independent con-t r i b u t i o n t o a c c u r a t e i n t e r p r e t a t i o n , e x c l u s i v e of t h a t p r o v i d e d by non-v e r b a l i n f o r m a t i o n . A common t a s k f a c e d by i n d i v i d u a l s i n m e d i c a l d i a g n o s t i c s e t t i n g s i s to e v a l u a t e whether, o r to what e x t e n t , p a i n i s p r e s e n t i n a g i v e n p a t i e n t . S i n c e t h e r e i s no s i n g l e , o b j e c t i v e c r i t e r i o n r e f l e c t i n g the s e v e r i t y of p a i n , and s i n c e a m b i g u i t y a s . t o the p r e s e n c e and s e v e r i t y of symptoms may e x i s t , the p h y s i c i a n must c o n s i d e r and a s s i g n d i f f e r e n t i a l w e i g h t s to a v a r i e t y o f f a c t o r s i n coming up w i t h an o v e r a l l e v a l u a t i o n . I n s uch s i t u a t i o n s , the d i a g n o s t i c i a n r e l i e s h e a v i l y on the e x p r e s s i v e b e h a v i o u r o f the s u b j e c t i n f o r m u l a t i n g a d e c i s i o n . . , Spontaneous, n o n v e r b a l e x p r e s s i o n s of p a i n a r e c a r e f u l l y o b s erved and n o t e d . In c e r t a i n d i a g n o s t i c p r o c e d u r e s , such as p a l p a t i o n and t e s t i n g f o r range of m o t i o n , the phy-s i c i a n d e l i b e r a t e l y u n d e r t a k e s t o i n d u c e p a i n and c o n c l u d e s t h a t i t i s p r e -s e n t when he o r she o b s e r v e s some change i n n o n v e r b a l b e h a v i o u r , t h a t 13 i n d i c a t e s p a i n . S u c t v ^ r e l i a n c e on n o n v e r b a l b e h a v i o r i s c o n s i s t e n t w i t h e v i d e n c e t h a t c e r t a i n t y p e s o f n o n v e r b a l cue, p a r t i c u l a r l y f a c i a l e x p r e s -s i o n s , a r e l e s s s u b j e c t to d i s s i m u l a t i o n t h a n v e r b a l b e h a v i o u r (Ekman & F r i e s e n , 1969). The s i m i l a r i t y between d i a g n o s t i c d e c i s i o n s and s i g n a l - d e t e c t i o n t a s k s has f r e q u e n t l y been p o i n t e d o u t . Swets (1972, p . 8 ) , f o r example, noted t h a t : the d e t e c t i o n o f a weak s i g n a l by a p h y s i c i a n depends not o n l y upon h i s s e n s i t i v i t y but a l s o upon h i s d e c i s i o n b i a s . The d e c i s i o n b i a s , i n t u r n , depends upon the s u b j e c t i v e p r o b a b i l i t y o f the s i g n a l i n q u e s t i o n and upon t h e u t i l i t i e s o f t h e v a r i o u s p o s s i b l e d e c i s i o n outcomes. A l t h o u g h the r e l e v a n c e o f SDT methods to d i a g n o s t i c d e c i s i o n - m a k i n g p r o c e s s e s has f r e q u e n t l y been p o i n t e d out, r e l a t i v e l y few s t u d i e s have em-p l o y e d SDT methods t o i n v e s t i g a t e d i a g n o s t i c p r a c t i c e s . I n an analogue o f a c l i n i c a l d i a g n o s t i c s i t u a t i o n , Stenson, K l e i n m u n t z , & S c o t t (1975) a t -tempted to e v a l u a t e t h e a p p l i c a b i l i t y o f SDT methods to MMPI p r o f i l e a n a l y -s i s . S u b j e c t s were two e x p e r i e n c e d c l i n i c i a n s , e i g h t g r a d u a t e s t u d e n t s i n c l i n i c a l p s y c h o l o g y , and twel v e u n d e r g r a d u a t e s , I n s t r u c t i o n s were t o d i f -f e r e n t i a t e between 46 known abnormal MMPI p r o f i l e s and 80 known normal ones. One o f the two e x p e r t s was r e q u i r e d t o s o r t the p r o f i l e s i n t o 12 c a t e g o r i e s ; from l e a s t to most l i k e l y t o seek p s y c h o l o g i c a l t r e a t m e n t . The second e x p e r t s o r t e d the p r o f i l e s i n t o f i v e c a t e g o r i e s r a n g i n g from " d e f i -n i t e l y normal" t o " d e f i n i t e l y abnormal". C a l c u l a t i o n o f r e c e i v e r - o p e r a t i n g -c h a r a c t e r i s t i c (ROC) parameters based on h i t and f a l s e a f f i r m a t i v e p r o b a -b i l i t i e s r e v e a l e d t h a t t h e SDT p a r a m e t r i c assumptions o f n o r m a l i t y o f d i s -c r i m i n a t i v e d i s t r i b u t i o n s and e q u a l v a r i a n c e s were met f o r t h e s e d a t a . The two groups o f s t u d e n t judges s o r t e d the p r o f i l e s i n t o " h o s p i t a l i z e d " and "never h o s p i t a l i z e d " c a t e g o r i e s . Two types of b i a s i n g i n f o r m a t i o n were 14 employed. I n a m a n i p u l a t i o n d e s i g n e d t o a l t e r s u b j e c t i v e p r o b a b i l i t i e s , 10 o f the s t u d e n t s were t o l d t h a t the p r o p o r t i o n o f t h e p r o f i l e s t h a t be-lo n g e d i n the " h o s p i t a l i z e d " p i l e was e i t h e r 30% or 70%. The o t h e r 10 s t u d e n t s were g i v e n one o f two s e t s o f i n s t r u c t i o n s emphasizing d i f f e r i n g u t i l i t i e s of the d i a g n o s t i c d e c i s i o n . F i v e s t u d e n t s were t o l d t h a t hos-p i t a l i z a t i o n was c o s t l y and s t i g m a t i z i n g ; the o t h e r f i v e s t u d e n t s were t o l d t h a t the p a t i e n t s were dangerous t o s o c i e t y . T h i s m a n i p u l a t i o n of p r o b a b i l i t i e s and c o s t s produced no e f f e c t s on d' v a l u e s among groups. That t h e a u t h o r s r e p o r t e d o n l y the c h a r a c t e r i s t i c s o f d' ( s e n s i t i v i t y ) and not r e s p o n s e b i a s as a f u n c t i o n o f the i n s t r u c t i o n a l m a n i p u l a t i o n t e s t i f i e s to the n e g l e c t o f the r e s p o n s e b i a s parameter i n d i s c u s s i o n s o f d i a g n o s t i c d e c i s i o n - m a k i n g . I n an a p p l i c a t i o n o f SDT methods t o the a n a l y s i s o f the p e r c e p t i o n o f s o c i a l c ues, Thompson (1978) had 83 s u b j e c t s j udge how s u r e they were t h a t a p p r o v a l had o r had not been g i v e n i n . e a c h o f 104 v i d e o t a p e d remarks t a k e n from scenes d e p i c t i n g a c o l l e g e p r o f e s s o r commenting t o a s t u d e n t about a s u b m i t t e d paper. M u l t i p l e r e g r e s s i o n a n a l y s i s i n d i c a t e d t h a t s e v e r a l v a r i a b l e s p r e d i c t e d the n o n - p a r a m e t r i c measure o f s e n s i t i v i t y (A', G r i e r , 1971): age, sex, need f o r a p p r o v a l and l o c u s o f c o n t r o l . L u s t e d (1971) summarized s t u d i e s u s i n g SDT comparisons o f d i a g n o s e s based on c h e s t X - r a y s through d i r e c t p l a t e v i e w i n g . D i r e c t v i e w i n g y i e l d e d s i g n i f i c a n t l y l a r g e r d' v a l u e s , measuring the d i a g n o s t i c i a n s ' a b i l i t y t o d i s c r i m i n a t e known p o s i t i v e from n e g a t i v e p l a t e s . I n t h i s f i e l d , SDT p r o -cedures have a l s o been employed t o a s s e s s the e f f e c t o f t r a i n i n g on t e c h -n i c i a n s ' d i a g n o s t i c a c c u r a c y i n j u d g i n g c h e s t X - r a y s , and to compare the a c c u r a c y i n d i s c r i m i n a t i n g cancerous from noncancerous mammograms, of e x p e r i e n c e d r a d i o l o g i s t s compared to s e c r e t a r i e s and X-ray t e c h n i c i a n s . 15 I n l a t e r work L u s t e d (1975) has a p p l i e d SDT methods to remote TV v i e w i n g of n u c l e a r imaging scans ( s c i n t i g r a m s ) . D i a g n o s i s based on r e -mote v i e w i n g was as a c c u r a t e under c e r t a i n c o n d i t i o n s as t h a t based on d i r e c t v i e w i n g ; thus s a t e l l i t e s t a t i o n s t h a t c o u l d not j u s t i f y h i r i n g h i g h - s a l a r i e d f u l l - t i m e n u c l e a r d i a g n o s t i c i a n s c o u l d t r a n s m i t d i a g n o s t i c s c i n t i g r a m s to a c e n t r a l l o c u s f o r r e l i a b l e e v a l u a t i o n . I n t h e i r r e v i e w o f c l i n i c a l p s y c h o p h y s i c s , G o r s s b e r g and Grant (1978) n o t e o t h e r a p p l i c a -t i o n s . F o r example r e c e n t work has employed SDT methods f o r l e s i o n l o c a -l i z a t i o n (Metz, S t a r r & L u s t e d , 1976; S t a r r , Metz, L u s t e d , & Goodenough, 1975) and d e t e c t i o n o f lumps i n the human female b r e a s t (Adams e t a l . , 1976) . P r k a c h i n (1978) extended SDT methodology to an a n a l y s i s o f the e f f e c t s o f s o c i a l models on n o n - v e r b a l p a i n b e h a v i o r . The s t u d y was d e s i g n e d to i n v e s t i g a t e two i s s u e s : 1) whether o b s e r v e r s c o u l d i n f a c t d i s c r i m i n a t e e x p r e s s i v e b e h a v i o r r e s u l t i n g from d i f f e r e n t i n t e n s i t i e s of n o x i o u s s t i m u -l a t i o n , and 2) whether o b s e r v e r s ' r a t i n g s of the e x p r e s s i v e b e h a v i o r of s u b j e c t s exposed to t o l e r a n t or i n t o l e r a n t m odeling or c o n t r o l c o n d i t i o n s would e x h i b i t s y s t e m a t i c v a r i a t i o n s . V i d e o t a p e s t a k e n o f s u b j e c t s under-g o i n g one o f t h r e e m o d e l i n g . c o n d i t i o n s i n a p r e v i o u s experiment were p r e -s e n t e d t o o b s e r v e r s who attempted to p r e d i c t the l e v e l s o f c u r r e n t t h a t ob-s e r v e d s u b j e c t s were e x p e r i e n c i n g . SDT a n a l y s e s of o b s e r v e r s ' judgments i n d i c a t e d t h a t r e s p o n s e s to i n t e n s e s t i m u l i were more r e a d i l y d i s c r i m i n a t e d than r e s p o n s e s to l e s s i n t e n s e s t i m u l i . The b e h a v i o u r o f s u b j e c t s exposed to a t o l e r a n t model was l e s s d i s c r i m i n a b l e than t h a t o f i n t o l e r a n t s u b j e c t s . The b e h a v i o r of i n t o l e r a n t s was l e s s d i s c r i m i n a b l e than t h a t of c o n t r o l s . I t was argued t h a t t o l e r a n t m o d e l i n g produces r e d u c t i o n s i n o v e r t , non-v o c a l e x p r e s s i o n s of p a i n . 16 The SDT p e r s p e c t i v e on d i a g n o s t i c p r o c e s s e s emphasizes the n o t i o n t h a t a p a r t i c u l a r d e c i s i o n r e g a r d i n g the p r e s e n c e and s e v e r i t y o f symp-toms r e f l e c t s the o p e r a t i o n o f two f a c t o r s : 1) e v i d e n c e t h a t a p a r t i c u l a r phenomenon i s p r e s e n t i n the p a t i e n t , and 2) the d i a g n o s t i c i a n ' s r e a d i n e s s t o a c c e p t weak o r s t r o n g e v i d e n c e as i n d i c a t i n g the p r e s e n c e o f the i n -f e r r e d phenomenon. I n the c a s e o f p a i n e v a l u a t i o n s , t h i s p e r s p e c t i v e sug-g e s t s t h a t a d i a g n o s t i c i a n ' s d e c i s i o n r e g a r d i n g i t s p r e s e n c e and s e v e r i t y i s d e t e r m i n e d o n l y p a r t i a l l y by the o c c u r r e n c e of b e h a v i o u r i n d i c a t i v e o f p a i n . The f i n a l e v a l u a t i o n w i l l a d d i t i o n a l l y r e f l e c t the o b s e r v e r ' s t e n -dency t o r e q u i r e l i t t l e o r much e v i d e n c e b e f o r e c o n c l u d i n g t h a t p a i n i s p r e s e n t . As p o i n t e d out by Swets (1972), the v a l u e of the o b s e r v e r ' s c r i -t e r i o n w i l l be determined by the u t i l i t i e s a s s o c i a t e d w i t h a p a r t i c u l a r d e c i s i o n and by the d i a g n o s t i c i a n ' s s u b j e c t i v e assessment of the p r o b a b i l i -t i e s o f p a i n . I n p a i n e v a l u a t i o n s , a wide v a r i e t y of v a r i a b l e s a r e l i k e l y t o p l a y an i m p o r t a n t r o l e i n d e t e r m i n i n g the d i a g n o s t i c i a n ' s c r i t e r i o n f o r a c c e p t -i n g a p a r t i c u l a r s e t of e v i d e n c e as i n d i c a t i v e of p a i n . Background d a t a about the p a t i e n t ' s p e r s o n a l c h a r a c t e r i s t i c s , the h i s t o r y o f the problem, i t s r e s p o n s e to t r e a t m e n t , and o t h e r p a i n - r e l e v a n t phenomena are a t the c l i n i c i a n ' s d i s p o s a l and a r e c o n s i d e r e d when an e v a l u a t i o n i s f o r m u l a t e d . While no s y s t e m a t i c r e s e a r c h i n t o t h e s e p r o c e s s e s has been conducted, c l i n i c a l e x p e r i e n c e p r o v i d e s many examples. F o r example p a i n p a t i e n t s who d i s p l a y e v i d e n c e of the c o n c o m i t a n t p r e s e n c e of p s y c h i a t r i c d i s t u r b a n c e a r e l i k e l y t o be branded as " c r o c k s " ( S t e r n b a c h , 1974). T h i s i s l i k e l y t o have the consequence o f the c l i n i c i a n r e q u i r i n g an abundance o f e v i d e n c e o f p a i n b e f o r e c o n c l u d i n g t h a t a s i g n i f i c a n t p a i n problem i s p r e s e n t . S i m i l a r l y , a common assumption i n c l i n i c a l s e t t i n g s ( s u p p o r t e d by some 17 r e s e a r c h ) i s t h a t c e r t a i n e t h n i c groups re s p o n d d i f f e r e n t i a l l y to s i m i l a r amounts of p a i n (Weisenberg, 1977). Examples of t h i s i n c l u d e the p r e v a -l e n t b e l i e f t h a t M e d i t e r r a n e a n p e o p l e a r e e x c e s s i v e l y r e a c t i v e to m i n i m a l n o x i o u s s t i m u l a t i o n , w h i l e O r i e n t a l s tend to be s t o i c a l and f o r e b e a r i n g of g r e a t amounts o f p a i n . A d i a g n o s t i c i a n p r e s e n t e d w i t h i n f o r m a t i o n r e -g a r d i n g the p a t i e n t ' s e t h n i c background c o u l d be e x p e c t e d to be l e s s or more w i l l i n g to a c c e p t m a n i f e s t e v i d e n c e as i n d i c a t i v e o f p a i n i n t h e s e two r e s p e c t i v e i n s t a n c e s . F o r the p a i n r s u f f e r e r , the d e c i s i o n b i a s of h i s a t t e n d i n g d i a g n o s t i c i a n i s c r i t i c a l . A b i a s t o i n t e r p r e t e x p r e s s i v e be-h a v i o r as i n d i c a t i v e t h a t l i t t l e p a i n i s p r e s e n t may have d r a s t i c conse-quences on subsequent c a r e t a k i n g r e s p o n s e s . The p r e s e n t s t u d y was an attempt t o s y s t e m a t i c a l l y examine some o f the a f o r e m e n t i o n e d i s s u e s by means of SDT methodology. One p a r t of the experiment was d e s i g n e d as an attempt to r e p l i c a t e P r k a c h i n ' s (1978) f i n d -i n g t h a t exposure of s u b j e c t s e x p e r i e n c i n g p a i n to d i f f e r e n t i a l l y t o l e r a n t s o c i a l models a f f e c t s o b s e r v e r s ' a b i l i t y t o d i s c r i m i n a t e t h e i r b e h a v i o r . O b s e r v e r s r a t e d v i d e o t a p e s o f the b e h a v i o r of s u b j e c t s from P r k a c h i n ' s experiment, exposed to one of t h r e e c o n d i t i o n s d e s i g n e d t o i n f l u e n c e t h e i r r e a c t i o n t o n o x i o u s e l e c t r i c a l s t i m u l a t i o n : t o l e r a n t m o d e l i n g , i n t o l e r a n t m o d e l i n g , and exposure to an i n a c t i v e companion. O b s e r v e r s made judgments as t o the l e v e l o f p a i n t h a t o b s e r v e d s u b j e c t s were e x p e r i e n c i n g . P r k a c h i n ' s paradigm was m o d i f i e d s i g n i f i c a n t l y i n the p r e s e n t s t u d y . The number o f o b s e r v e d s u b j e c t s was i n c r e a s e d from 9 to 30 f o r each o b s e r v e r . I n P r k a c h i n ' s s t u d y each o b s e r v e r examined a r e l a t i v e l y l o n g sequence of b e h a v i o r (54 s t i m u l u s p r e s e n t a t i o n s ) f o r o n l y 9 s u b j e c t s . I n the p r e s e n t s t u d y , the f i r s t s i x p r e s e n t a t i o n s each of low, medium, and h i g h e l e c t r i c c u r r e n t s were;taken from each o f 30 s u b j e c t s . S e l e c t i o n o f t h e s e e a r l y 18 t r i a l s f o r r a t i n g by o b s e r v e r s a l l o w e d an assessment of the r e l a t i v e l y immediate impact on shocked s u b j e c t s of exposure to the v a r i o u s s o c i a l c o n d i t i o n s . I t was e x p e c t e d t h a t o b s e r v e r s r a t i n g s u b j e c t s exposed to t o l e r a n t o r i n t o l e r a n t models would e x p e r i e n c e p o o r e r d i s c r i m i n a b i l i t y t h a n o b s e r v e r s r a t i n g s u b j e c t s i n the c o n t r o l c o n d i t i o n . A second f o c u s of the p r e s e n t experiment was to s y s t e m a t i c a l l y eva-l u a t e the impact of a p r i o r i p a i n - r e l e v a n t i n f o r m a t i o n on o b s e r v e r s ' r e a d i n e s s to r e p o r t the o c c u r r e n c e of p a i n i n o t h e r s . Two types of b i a s -i n g i n f o r m a t i o n were p r e s e n t e d to o b s e r v e r s p r i o r to o b s e r v i n g the v i d e o -t a p e s . I n one c o n d i t i o n , i n t e n d e d t o d e c r e a s e o b s e r v e r s ' tendency to r e -p o r t the o c c u r r e n c e of p a i n i n o b s e r v e d s u b j e c t s , o b s e r v e r s were t o l d t h a t s u b j e c t s had r e c e i v e d two t a b l e t s o f an a n a l g e s i c drug b e f o r e u n d e r g o i n g the s e r i e s of e l e c t r i c s h o c k s . In a n o t h e r c o n d i t i o n , i n t e n d e d to i n c r e a s e t e n d e n c i e s to r e p o r t p a i n i n o b served s u b j e c t s , o b s e r v e r s were t o l d t h a t s u b j e c t s had been a d m i n i s t e r e d a p a i n enhancing treatment p r i o r t o under-g o i n g t h e s e r i e s o f e l e c t r i c s h o c k s . The i n f l u e n c e o f t h e s e t r e a t m e n t s was a s s e s s e d i n r e l a t i o n t o a group of s u b j e c t s who r e c e i v e d no p r i o r i n -f o r m a t i o n . 19 METHOD Subj e c t s T h i r t y u n dergraduate v o l u n t e e r s (15 males, 15 females) were r e -c r u i t e d from I n t r o d u c t o r y P s y c h o l o g y c o u r s e s a t the U n i v e r s i t y of B r i t i s h Columbia (males' mean age = 19.87, S.D. . = 2.53; f e m a l e s ' mean age = 19.13, S.D. = 2.29). S u b j e c t s were c o n t a c t e d by t e l e p h o n e and s o l i c i t e d f o r p a r t i c i p a t i o n i n an experiment on "the i n f l u e n c e of v a r i o u s t r e a t m e n t s on the e x p e r i e n c e of p a i n . " Of t h o s e who a r r i v e d a t the l a b o r a t o r y f o r the s e s s i o n , none r e f u s e d to p a r t i c i p a t e . Apparatus and E x p e r i m e n t a l Environment Two v i d e o t a p e s were shown to s u b j e c t s on a 2 3 - i n c h t e l e v i s i o n s e t v i a a Sony AV3400 v i d e o t a p e r e c o r d e r p l a y b a c k u n i t . The v i d e o t a p e s d e p i c t e d samples of b e h a v i o u r of t h i r t y s u b j e c t s who had t a k e n p a r t i n a p r e v i o u s experiment ( P r k a c h i n , 1978). I n the p r e v i o u s experiment, s u b j e c t s were exposed to a s e r i e s of e l e c t r i c shock r a n g i n g from 0.0 m i l l i a m p e r e s to i n t e n s i t i e s t h a t were j u d g e d by the s u b j e c t t o be p a i n f u l enough t h a t U t h e y d i d not w i s h to t o l e r a t e any g r e a t e r . The e x e r p t s on the v i d e o t a p e d e p i c t e d t h e r e s p o n s e s of t h e s e s u b j e c t s t o t h r e e s e t s of p a i r s of e l e c t r i c shocks o c c u r r i n g i n a random o r d e r . The t h r e e p a i r s of shocks had been r a t e d by t h e s u b j e c t s on the v i d e o t a p e s as a p p r o x i m a t e l y s e n s a t i o n t h r e s h o l d ( l o w ) , s l i g h t l y below p a i n t h r e s h o l d (medium), and halfway between„pain t h r e s -h o l d and p a i n t o l e r a n c e ( h i g h ) . P a i r s of s t i m u l i from each of t h e s e l e v e l s d i f f e r e d by 0.25 m i l l i a m p e r e s i n c u r r e n t i n t e n s i t y and were d e l i v e r e d a p p r o x i m a t e l y one t o two seconds a p a r t . Thus, each t r i a l on 20 t h e v i d e o t a p e c o n s i s t e d of t h e r e a c t i o n o f t h e s u b j e c t t o t h e p r e s e n t a -t i o n o f two e l e c t r i c shocks a t t h r e e l e v e l s of c u r r e n t i n t e n s i t y . The s u b j e c t s ( h e n c e f o r t h r e f e r r e d to as " s e n d e r s " ) r a t e d each c u r -r e n t on a 7 - p o i n t c a t e g o r i c a l judgement s c a l e w h i l e b e i n g exposed to one of t h r e e s o c i a l i n f l u e n c e c o n d i t i o n s d e s i g n e d t o a f f e c t t h e i r r e a c t i o n s to the shock. I n one c o n d i t i o n ( t o l e r a n t ) , s e n d e r s had been exposed t o a c o n f e d e r a t e model who d i s s i m u l a t e d r e l a t i v e t o l e r a n c e t o -ward t h e e l e c t r i c a l s t i m u l a t i o n . I n another c o n d i t i o n ( i n t o l e r a n t ) , s enders had been exposed to a model who d i s s i m u l a t e d r e l a t i v e i n t o l e r a n c e toward the s t i m u l a t i o n . I n the t h i r d c o n d i t i o n ( c o n t r o l ) senders had s i m p l y been exposed to an i n a c t i v e co-companion. The v i d e o t a p e s employed i n t h i s study sampled the b e h a v i o u r of senders d u r i n g t h e i n i t i a l t r i a l s o f t h e i r exposure to randomly o c c u r r i n g e l e c t r i c a l s t i m u l a t i o n . The f i r s t s i x p r e s e n t a t i o n s of each s t i m u l u s l e v e l t o each sender were sampled. Thus t h e v i d e o t a p e s com-p r i s e d a sequence of 180 s t i m u l u s p r e s e n t a t i o n s , c o n t a i n i n g 60 s t i m u l u s p r e s e n t a t i o n s of senders i n each of t h e t h r e e s o c i a l i n f l u e n c e c o n d i -t i o n s . The v i d e o t a p e s were 56 minutes i n l e n g t h . Each e x c e r p t showed the s e n d e r s ' upper b o d i e s from about the m i d d l e of the t o r s o up to t h e f a c e (the hands were u s u a l l y not v i s i b l e ) . To the r i g h t o f the sender, a t about h e a d - l e v e l , was a l i g h t which came on a t i n i t i a l shock p r e s e n t a t i o n , and t e r m i n a t e d f i v e seconds l a t e r . Each e x c e r p t of the b e h a v i o u r of a sender o c c u r r e d i n the f o l l o w i n g sequence. F o l l o w i n g s e v e r a l seconds o f TV b l a c k , t h e sender was shown p r i o r t o t h e p r e s e n t a t i o n of the shocks. T h i s exposure was measured i n tape to be one f o o t l o n g ( a p p r o x i m a t e l y two s e c o n d s ) . Then 21 the l i g h t b e s i d e the sender's head came on f o r f i v e seconds and t h e scene was c u t one second a f t e r the l i g h t went out. Thus, each e x c e r p t o c c u p i e d a t o t a l exposure time o f e i g h t seconds. E i g h t t o t e n seconds o f TV b l a c k s e p a r a t e d each t r i a l to g i v e t h e o b s e r v e r s u f f i c i e n t time to make a r a t i n g . Above t h e t e l e v i s i o n s c r e e n was mounted a sh e e t o f c a r d b o a r d d i s -p l a y i n g the f o l l o w i n g r a t i n g c a t e g o r i e s t h a t s u b j e c t s were to employ i n the experiment: A-UNDECTABLE, B-POSSIBLE SENSATION, C-NON-PAIN SENSATION, D-VERY FAINT PAIN, E-MILD PAIN, F-MODERATE PAIN, G-STRONG PAIN. T h i s s c a l e was i d e n t i c a l t o t h a t used by P r k a c h i n (1978) save one word. The e x p e r i m e n t a l room c o n t a i n e d t h e A/V equipment, a t a b l e , and f o u r c h a i r s . S u b j e c t s s a t a t a s e l f - c h o s e n d i s t a n c e from the t e l e v i s i o n monitor., r a n g i n g from two t o f o u r f e e t . The e x p e r i m e n t e r s a t b e s i d e t h e s u b j e c t , f a c i n g the s c r e e n and r e c o r d i n g the o r a l l y -g i v e n r e s p o n s e s on a c o d i n g s h e e t . P r o c e d u r e Upon a r r i v a l a t t h e l a b o r a t o r y s u b j e c t s were g r e e t e d and r e q u e s t e d t o t a k e a s e a t . The exp e r i m e n t e r i n f o r m e d them t h a t t h e i n s t r u c t i o n s f o r the s t u d y were t a p e - r e c o r d e d and t h a t he w o u l d ' o c c a s i o n a l l y be ad d i n g e x p l a n a t i o n s to them. They were a l s o t o l d t h a t they c o u l d i n t e r r u p t anytime i f they had q u e s t i o n s . The t a p e - r e c o r d e r was then t u r n e d on and the s u b j e c t l i s t e n e d t o the f o l l o w i n g p r e l i m i n a r y i n s t r u c t i o n s : " I n t h i s study we a r e i n v e s t i g a t i n g how p e o p l e respond to o t h e r s i n d i s t r e s s . More s p e c i f i c a l l y , we a r e i n t e r e s t e d i n how w e l l you i d e n t i f y and judge t h e e x p r e s s i v e b e h a v i o u r of o t h e r p e o p l e who a r e e x p e r i e n c i n g v a r i o u s l e v e l s of p a i n . 22 F i r s t , i f you wish to p a r t i c i p a t e you may g i v e your c o n s e n t . " The s u b j e c t s were th e n g i v e n the consent form (Appendix A) t o r e a d and s i g n . A l l s u b j e c t s gave t h e i r consent t o take p a r t . F o l l o w i n g t h i s , s u b j e c t s were r e q u e s t e d to complete a q u e s t i o n n a i r e measure o f e m o t i o n a l empathy (Mehrabian & E p s t e i n , 1972). A f t e r s u b j e c t s had f i l l e d out the q u e s t i o n n a i r e , the tape r e c o r d e r was t h e n t u r n e d back on. A t t h i s p o i n t s u b j e c t s l i s t e n e d to t h e f o l l o w i n g s t a n d a r d i n -s t r u c t i o n s : " F i r s t o f a l l , some d e s c r i p t i o n may h e l p you under-s t a n d what i s happening. The p e o p l e t h a t you w i l l be w a t c h i n g t o o k r p a r t i n an experiment on the p e r -c e p t i o n o f p a i n . " Depending on t h e e x p e r i m e n t a l group to which t h e s u b j e c t ( h e n c e f o r t h r e f e r r e d t o as " o b s e r v e r " ) had been a s s i g n e d , one o f t h e f o l l o w i n g s e t s of i n s t r u c t i o n s t h e n o c c u r r e d . Sandpaper (S) group. "They (the se n d e r s ) were s e a t e d i n the l a b o r a t o r y and as p a r t of the experiment, an a b r a s i v e s u r -f a c e t h a t produces p a i n h y p e r s e n s i t i v i t y was rubbed on t h e i r f orearm, a f t e r which they had an e l e c t r o d e a t t a c h e d to t h e i r arm .on the s e n s i t i z e d area.:. Then they were exposed t o a s e r i e s o f e l e c t r i c shocks of v a r y i n g i n t e n s i t i e s . These shocks were p r e s e n t e d over and over t o the s u b j e c t many ti m e s . The p a r t i c u l a r type of s u r f a c e , r o u g h l y a k i n t o a medium grade sandpaper, t h a t each s u b j e c t e l e c t e d t o have a d m i n i s t e r e d t o her fo r e a r m has a p a i n - e n h a n c i n g p r o p e r t y t h a t l a s t s f o r 2 t o 4 h o u r s . A l l s u b j e c t s had the o p t i o n of d i s c o n t i n u i n g the experiment a t any time. Your purpose i s to p r o v i d e r a t i n g s t h a t w i l l e n a b l e assessment o f the e f f e c t o f t h e a b r a s i v e s u r f a c e on p a i n s e n s i t i v i t y . " Darvon (D) group: "They were s e a t e d i n the l a b o r a t o r y and had an 23 e l e c t r o d e a t t a c h e d t o t h e i r arm. As p a r t o f the experiment, each p e r s o n was g i v e n two a n a l -g e s i c or p a i n - r e l i e v i n g t a b l e t s which they i n -g e s t e d b e f o r e p r o c e e d i n g . Then they were ex-posed t o a s e r i e s of e l e c t r i c shocks o f v a r y i n g i n t e n s i t i e s . These shocks were p r e s e n t e d over and over t o t h e s u b j e c t many t i m e s . "The p a r t i c u l a r type o f t a b l e t , Darvon, t h a t each s u b j e c t e l e c t e d t o t a k e , has a p a i n -r e d u c i n g p r o p e r t y t h a t l a s t s f o r 2 to 4 h o u r s . Your purpose i s to p r o v i d e r a t i n g s , t h a t w i l l e n a b l e assessment of t h e e f f e c t o f the t a b l e t s on p a i n s e n s i t i v i t y . " C o n t r o l (C) group. "They were s e a t e d i n t h e l a b o r a t o r y and had an e l e c t r o d e a t t a c h e d t o t h e i r arm. Then they were exposed t o a s e r i e s o f e l e c t r i c shocks of v a r y i n g i n t e n s i t i e s . These shocks were p r e -s e n t e d over and over t o the s u b j e c t many, t i m e s . " F o l l o w i n g exposure t o one of the above i n s t r u c t i o n a l m a n i p u l a t i o n s , i n s t r u c t i o n s c o n t i n u e d as f o l l o w s f o r o b s e r v e r s i n a l l groups. The v i d e o t a p e was t u r n e d on, d i s p l a y i n g a sample o f sender b e h a v i o u r . "Each time t h e l i g h t goes ion i n the f i l m the p e r s o n was shocked t w i c e f o r about a h a l f second." Then t h e r e was a f i v e second pause w h i l e t h e l i g h t came on i n the f i l m . " A f t e r the l i g h t has been on f o r two seconds, the shocks end, and the p e r s o n d e s c r i b e s i n words how the shock f e l t . You w i l l l o o k a t t h e s c r e e n and each time t h e l i g h t goes on, t r y to determine how much p a i n t h e p e r s o n i s f e e l i n g . I n f r o n t o f you i s a c h a r t p r o v i d i n g a s c a l e f o r r a t i n g the per s o n ' s p a i n . The s c a l e goes from A to G. In each c a s e , y o u ' l l l o o k a t t h e s c r e e n and each time the l i g h t goes on you w i l l view t h e p e r s o n r e c e i v i n g two b r i e f s h o c k s . Then a f t e r the shocks end, you w i l l l o o k a t the s c a l e and choose a l e t t e r from A t o G t h a t b e s t c o r r e s p o n d s t o how much p a i n t h e p e r s o n i n t h e f i l m seemed t o be f e e l i n g , u p o n r e c e i v i n g the s h o c k s . You w i l l t h e n say t h e l e t t e r o ut l o u d . I f you have any q u e s t i o n s , p l e a s e ask them now." 24 A t t h i s p o i n t , o b s e r v e r s were encouraged to ask q u e s t i o n s and t h e tape was t u r n e d o f f . Some a d d i t i o n a l d e s c r i p t i o n about t h e s c a l e was g i v e n by t h e ex p e r i m e n t e r . "The s c a l e goes from weak to s t r o n g ... a r a t i n g o f "A" means i t l o o k e d l i k e the p e r s o n c o u l d n ' t f e e l a n y t h i n g ... . a "B" means i t l o o k e d as though the p e r s o n MAY have f e l t something but they may NOT have, y o u ' r e not r e a l l y s u r e . A "C" means i t l o o k e d as though the p e r s o n d e f i n i t e l y d i d f e e l something, but i t was not p a i n f u l . A "D" means they d i d f e e l something and i t WAS p a i n f u l . The o t h e r r a t i n g s s t a n d f o r s u c c e s s i v l e y h i g h e r p a i n s e n s a t i o n s . I s t h a t c l e a r ? "Now, w e ' l l t r y a few p r a c t i c e t r i a l s . B e f o r e we b e g i n , I want t o draw your a t t e n t i o n to one t h i n g . There i s no sound on t h e s e v i d e o t a p e s . I n t h e experiment i t s e l f , the s u b j e c t s • c o u l d hear a sound t h a t i n d i c a t e d t o them when t h e shock was b e i n g a d m i n i s t e r e d . I t was a c l i c k i n g n o i s e . S i n c e t h e l i g h t i n t h e f i l m s t a y s on f o r 5 seconds, i t tends t o d e c e i v e p e o p l e i n t o t h i n k i n g t h a t the shock l a s t s f o r 5 seconds. So f o r the p r a c t i c e t r i a l s , I ' l l s i m u l a t e t h e sound t h a t the s u b j e c t h e a r s so t h a t you get t h e i d e a of how l o n g t h e shocks a c t u a l l y l a s t e d . " Then s i x p r a c t i c e t r i a l s were-.run, w i t h t h e exp e r i m e n t e r simu-l a t i n g the c l i c k i n g n o i s e t h a t o c c u r r e d a t t h e on s e t of each shock. A t the end of the p r a c t i c e t r i a l s , the tape r e c o r d e r was t u r n e d on a g a i n , and o b s e r v e r s l i s t e n e d t o the f o l l o w i n g s e t o f i n s t r u c t i o n s . "Remember t o pay c l o s e a t t e n t i o n t o t h a t f i r s t two seconds because t h a t i s when t h e p e r s o n i s b e i n g shocked. The b e h a v i o u r o f the p e r s o n AFTER t h e two second p e r i o d shows her making up her mind about the shock she j u s t r e c e i v e d and d e s c r i b i n g i t . Here a r e some f i n a l p o i n t s . F i r s t , when making your r a t i n g s on the s c a l e , t r y to s p r e a d your resp o n s e s out, t h a t i s , t r y to use a l l o f the c a t e g o r i e s from A to G. A v o i d r e p e a t i n g the same l e t t e r over and o v e r . Second, some p e o p l e w i l l be easy t o ju d g e , o t h e r s may seem q u i t e d i f -f i c u l t . P l e a s e pay c l o s e a t t e n t i o n and t r y to do your b e s t throughout. T h i r d , i t may have o c c u r r e d to you t h a t t h e p e o p l e y o u ' l l be s e e i n g a r e not 25 r e a l l y b e i n g shocked a t a l l , but a r e j u s t f a k i n g i t . T h i s i s not the c a s e . On each t r i a l , e v e r y s u b j e c t i s r e c e i v i n g a shock. F o u r t h , the t r i a l s appear i n random o r d e r and do not n e c e s s a r i l y f o l l o w an a c t u a l sequence i n time. Now you w i l l have some more p r a c t i c e t r i a l s . " A t t h i s p o i n t , o b s e r v e r s had s i x more p r a c t i c e t r i a l s , w i t h e x p e r i m e n t e r s u b s t i t u t i n g t h e word "NOW" a t the p o i n t a t which the shock ended on each t r i a l . O b s e r v e r s were th e n asked i f they f e l t they had had enough p r a c t i c e . A l l i n d i c a t e d t h a t they had had enough. F i n a l l y , t h e tape r e c o r d e r was t u r n e d on a g a i n , and t h e f o l l o w i n g i n s t r u c t i o n s were g i v e n . "Now you w i l l see more v i d e o t a p e s of p e o p l e ex-p e r i e n c i n g d i f f e r e n t l e v e l s o f p a i n . We a r e i n t e r e s t e d a g a i n i n how w e l l you can determine how much p a i n they a r e f e e l i n g . A t t h i s p o i n t I w i l l remind you a g a i n : when making your r a t i n g s on the s c a l e , t r y to s p r e a d your r e s p o n s e s o u t ; t h a t i s , make s u r e to use a l l of t h e c a t e g o r i e s from A to G. T r y to a v o i d r e p e a t i n g the same l e t t e r over and o v e r . I f you have any q u e s t i o n s ,. p l e a s e ask them now." At t h i s p o i n t t h e e x p l i c i t i n s t r u c t i o n s about the t r e a t m e n t ( e i t h e r sandpaper, darvon, or c o n t r o l ) were r e p e a t e d as above. Darvon and Sandpaper o b s e r v e r s were then asked i f they u n d e r s t o o d t h e p r o c e d u r e d e s c r i b e d . A l l i n d i c a t e d t h a t they had. The e x p e r i -m e n t a l t a s k t h e n began. F o l l o w i n g c o m p l e t i o n of t h e t a s k , o b s e r v e r s completed a two-page d e b r i e f i n g q u e s t i o n n a i r e (see Appendix B ) . The q u e s t i o n n a i r e c o n t a i n e d items a d d r e s s i n g observers;' u n d e r s t a n d i n g of t h e e x p e r i m e n t a l t a s k , o b s e r v e r s ' a t t i t u d e s toward the t a s k , and more s p e c i f i c a l l y , o b s e r v e r s ' b e l i e f s about the e f f e c t i v e n e s s of the t r e a t -ment (darvon o r sandpaper) on senders and on t h e i r own r a t i n g s . I t a l s o i n v e s t i g a t e d t h e importance of elements of the f i l m e d p r e s e n t a -t i o n i n t h e i r r a t i n g s . When the q u e s t i o n n a i r e had been completed, the 2 6 experiment was explained to the p a r t i c i p a n t s and any questions were answered. Subjects were then thanked for t h e i r p a r t i c i p a t i o n and requested not to t a l k about the experiment. 27 RESULTS For the purpose of SDT a n a l y s e s , the d i s c r i m i n a b i l i t y measure _ (Simpson & F i t t e r , 1973) was used. E i s a n o n - p a r a m e t r i c measure of d i s c r i m i n a b i l i t y d e f i n e d as f o l l o w s : _ , _ 2 i E = ^ A - V ^ s f + s ^ 2 ' A B where i and i a r e the average r a t i n g s g i v e n to the s t i m u l i A and B A. 15 2 2 and s and s a r e t h e v a r i a n c e s of t h e two r a t i n g d i s t r i b u t i o n s . E A a i s e q u i v a l e n t t o the a r e a under the r e c e i v e r o p e r a t i n g c u r v e , P ( A ) . Frequency t a b l e s were g e n e r a t e d f o r use i n the c a l c u l a t i o n o f a r e s p o n s e - b i a s measure, average s c a l e r a t i n g ( h e r e a f t e r r e f e r r e d to as A ) . T h i s measure was o b t a i n e d by t a k i n g the average of the 7 - p o i n t s c a l e r a t i n g s g i v e n by o b s e r v e r s t o samples of sender b e h a v i o u r e l i c i t e d by h i g h , medium, and low shock i n t e n s i t i e s , and was c a l c u l a t e d s e p a r a t e l y w i t h i n t o l e r a n t , c o n t r o l , and i n t o l e r a n t m o d e l i n g c o n d i t i o n s . The d a t a d e r i v e d were i n v e s t i g a t e d by a n a l y s i s of v a r i a n c e (ANOVA). Three p o t e n t i a l e f f e c t s were o f p r i n c i p a l i n t e r e s t i n t h e s e a n a l y s e s : (1) whether the SDT parameters v a r i e d s y s t e m a t i c a l l y as a f u n c t i o n of the d i s c r i m i n a t i o n t h a t o b s e r v e r s performed ( t h a t i s , d i d E_ and/or A d i f f e r between t h e h i g h v s . medium (HM) and medium v s . low (ML) d i s -c r i m i n a t i o n ) ; (2) whether the parameters v a r i e d s y s t e m a t i c a l l y as a f u n c t i o n o f the' m odeling c o n d i t i o n to which o b s e r v e d s u b j e c t s had been exposed; and (3) whether the parameters v a r i e d s y s t e m a t i c a l l y as a f u n c t i o n of the i n s t r u c t i o n a l c o n d i t i o n to which o b s e r v e r s were exposed. The a n a l y s i s of E was conducted a c c o r d i n g t o a 3 ( I n s t r u c t i o n a l 28 C o n d i t i o n ) x 2 (Sex) x 2 ( D i s c r i m i n a t i o n L e v e l ) x 3 (Modeling C o n d i t i o n ) , ANOVA w i t h r e p e a t e d measures on the l a s t two di m e n s i o n s . The a n a l y s i s of A was the same except t h a t the 3 l e v e l Shock I n t e n s i t y v a r i a b l e r e p l a c e d t h e D i s c r i m i n a t i o n v a r i a b l e o f the E_ a n a l y s i s . The a n a l y s i s o f E_ r e s u l t e d i n a s i g n i f i c a n t D i s c r i m i n a t i o n e f f e c t , F_(l,24) = 173.14, £ < -001, a s i g n i f i c a n t M o d e l i n g C o n d i t i o n e f f e c t , F(2,48) = 28.59, £ < .01, and a s i g n i f i c a n t Sex e f f e c t , F ( l , 2 4 ) = 8.75, p_ < .01. A s i g n i f i c a n t i n t e r a c t i o n o c c u r r e d between M o d e l i n g C o n d i -t i o n and D i s c r i m i n a t i o n L e v e l , F_(2,48) = 8.23, p_ < .001. E x a m i n a t i o n o f means r e v e a l e d t h a t E_ v a l u e s f o r the HM d i s c r i m i n a -t i o n were g r e a t e r t h a n t h o s e f o r the ML d i s c r i m i n a t i o n (mean E_ = 0.509 and -0.126, r e s p e c t i v e l y ) . Thus, t h e a b i l i t y t o d i s c r i m i n a t e shock-e l i c i t e d e x p r e s s i v e b e h a v i o u r was c l o s e l y r e l a t e d t o the magnitude o f c u r r e n t t h e o b s e r v e d s u b j e c t was exposed t o . Mean E_ v a l u e s f o r t h e s i g n i f i c a n t M o d e l i n g C o n d i t i o n main e f f e c t were 0.039 f o r group T, 0.248 f o r group I , and 0.288 f o r group C. The d i f f e r e n c e s between t h e t o l e r a n t group and t h e o t h e r two groups exceeded the c r i t i c a l v a l u e f o r Dunn's m u l t i p l e comparison p r o c e d u r e ( t ' D .01/2; 3,48 = .08). Thus, o b s e r v e r s e x h i b i t e d r e l i a b l y lower F, v a l u e s when o b s e r v i n g t h e b e h a v i o u r o f s u b j e c t s exposed t o a t o l e r a n t model than when they o b s e r v e d the b e h a v i o u r o f s u b j e c t s exposed t o an i n t o l e r a n t model o r t o c o n t r o l s . E x a m i n a t i o n of means r e v e a l e d t h a t E_ v a l u e s f o r male .observers were g r e a t e r t h a n t h o s e f o r female o b s e r v e r s (mean E = 0.232 and 0.151, r e s p e c t i v e l y . Thus, males e x h i b i t e d b e t t e r p e r f o r -mance i n d i s c r i m i n a t i n g s h o c k - e l i c i t e d e x p r e s s i v e b e h a v i o u r t h a n d i d f e m a l e s . 29 The s i g n i f i c a n t M o d e l i n g x D i s c r i m i n a t i o n i n t e r a c t i o n i s d e p i c t e d i n F i g u r e 1. T e s t of t h i s i n t e r a c t i o n f o r s i m p l e e f f e c t s i n d i c a t e d a s i g n i f i c a n t d i f f e r e n c e among M o d e l i n g C o n d i t i o n s a t t h e HM l e v e l of d i s c r i m i n a t i o n , F_(2,48) = 52.47, p_ < .01. T e s t f o r a s i m p l e e f f e c t between HM and ML l e v e l s o f d i s c r i m i n a t i o n r e v e a l e d a s i g n i f i c a n t d i f -f e r e n c e a t t o l e r a n t , F(2,48) = 20.09, p_ < .01, c o n t r o l , F(2,48) = 105.37, p_ < .01, and i n t o l e r a n t , F_(2,48) = 59.04, p_ < .01, m o d e l i n g c o n d i t i o n s . F u r t h e r p o s t - h o c a n a l y s i s (a = .05) w i t h Tukey's HSD p r o c e d u r e r e v e a l e d t h a t t h e s i g n i f i c a n t d i f f e r e n c e among M o d e l i n g C o n d i t i o n s a t t h e HM l e v e l o f d i s c r i m i n a t i o n o c c u r r e d between group T and the o t h e r two groups w i t h groups I and C not d i f f e r i n g , c r i t i c a l v a l u e = 0.17. Thus, the e x p r e s s i v e b e h a v i o u r of senders exposed to a t o l e r a n t model was s i g n i f i c a n t l y l e s s d i s c r i m i n a b l e r e l a t i v e t o sen d e r s exposed to an i n t o l e r a n t model or an i n a c t i v e companion,, a t t h e HM l e v e l o f d i s -c r i m i n a t i o n . R e s u l t s of the a n a l y s i s of A i n d i c a t e d a s i g n i f i c a n t main e f f e c t f o r I n s t r u c t i o n a l C o n d i t i o n , F_(2,24) = 4.22, p_ < .03, f o r D i s c r i m i n a -t i o n L e v e l , F(2,48) = 186.28, p_ < .001, and f o r M o d e l i n g C o n d i t i o n , F_(2,48) = 20.46, _ < .001. A s i g n i f i c a n t i n t e r a c t i o n o c c u r r e d between M o d e l i n g C o n d i t i o n and D i s c r i m i n a t i o n L e v e l , F_(4,96) = 26.37, p_ < .001. Mean A v a l u e s f o r t h e s i g n i f i c a n t I n s t r u c t i o n a l C o n d i t i o n main e f f e c t were 2.772 f o r group D, 2.963 f o r group C, and 3.466 f o r group S. The d i f f e r e n c e between groups S and D and t h e d i f f e r e n c e between S and C exceeded the c r i t i c a l v a l u e f o r Dunn's m u l t i p l e comparison p r o c e d u r e ( t T D .05/2; 3,24 = .45). Thus, o b s e r v e r s e x h i b i t e d " h i g h e r A v a l u e s when i n s t r u c t e d t h a t an a b r a s i v e ( s a n d p a p e r - l i k e ) 30 F i g u r e 1. I n t e r a c t i o n between M o d e l i n g C o n d i t i o n and D i s c r i m i n a t i o n l e v e l on t h e measure of d i s c r i m i n a t i o n (E) . 30CL. 31 s u r f a c e had been a d m i n i s t e r e d to the f o r e a r m of s u b j e c t s , r e l a t i v e t o ob-s e r v e r s i n s t r u c t e d t h a t s u b j e c t s were r e c e i v i n g darvon and r e l a t i v e to c o n t r o l s . Mean A v a l u e s f o r the s i g n i f i c a n t Shock I n t e n s i t y e f f e c t were 3.431 f o r h i g h , 2.959 f o r low, and 2.810 f o r medium l e v e l s o f shock. The d i f f e r -ences between a l l t h r e e means exceeded the c r i t i c a l v a l u e f o r Tukey's m u l t i p l e comparison p r o c e d u r e (0.13). Thus, o b s e r v e r s e x h i b i t e d r e l i a b l y lower A v a l u e s when o b s e r v i n g t h e b e h a v i o u r o f s u b j e c t s r e c e i v i n g h i g h l e v e l s o f shock r e l a t i v e to when they were o b s e r v i n g the b e h a v i o u r o f s u b j e c t s r e c e i v i n g low l e v e l s o f shock, and, p a r a d o x i c a l l y , they e x h i b i t e d even lower A v a l u e s when o b s e r v i n g the b e h a v i o u r of s u b j e c t s r e c e i v i n g medium l e v e l s o f shock. Mean A v a l u e s f o r the s i g n i f i c a n t M o d e l i n g C o n d i t i o n e f f e c t were 2.927 f o r group T, 3.068 f o r group I , and 3.205 f o r group C. The d i f f e r -ences between a l l t h r e e means exceeded the c r i t i c a l v a l u e f o r Tukey's m u l t i p l e comparison p r o c e d u r e (0.13). Thus o b s e r v e r s e x h i b i t e d r e -l i a b l y lower A v a l u e s when o b s e r v i n g the b e h a v i o u r o f s u b j e c t s exposed, to an i n t o l e r a n t model r e l a t i v e t o when they were o b s e r v i n g the b e h a v i o u r of c o n t r o l s , and they e x h i b i t e d even lower A v a l u e s when o b s e r v i n g the b e h a v i o u r o f s u b j e c t s exposed to a t o l e r a n t model r e l a t i v e to when they o b s e r v e d e i t h e r i n t o l e r a n t o r c o n t r o l s u b j e c t s . The s i g n i f i c a n t M o d e l i n g x Shock I n t e n s i t y i n t e r a c t i o n i s d e p i c t e d i n F i g u r e 2. A n a l y s e s of s i m p l e e f f e c t s i n d i c a t e d a s i g n i f i c a n t d i f -f e r e n c e among M o d e l i n g C o n d i t i o n s a t the h i g h shock i n t e n s i t y , F_(4,96) = 69.32, p_<.01. Po s t - h o c a n a l y s i s w i t h Tukey's HSD p r o c e d u r e r e v e a l e d t h a t a l l t h r e e M o d e l i n g C o n d i t i o n s d i f f e r e d s i g n i f i c a n t l y ( c r i t i c a l s a F i g u r e 2. Mean A (average p a i n r a t i n g ) v a l u e s as a f u n c t i o n of s ender's M o d e l i n g C o n d i t i o n and Shock I n t e n s i t y . ' ^ < ? C ; ^ , Note: A v a l u e of 1 = U n d e t e c t a b l e shock, a v a l u e of 7 = s t r o n g p a i n . 2.1 Tolerant Control IhtoLenuit MoietinOf condition Q£ sender 33 v a l u e = 0.15). T e s t f o r s i m p l e e f f e c t s among Shock I n t e n s i t y r e v e a l e d s i g n i f i c a n t d i f f e r e n c e s a t t o l e r a n t , F_(4,96) = 26.90, _ < ,01, c o n t r o l , F(4,96) = 344.81, _ < .01, and i n t o l e r a n t , F(4,96) = 135.49, _ < .01, mode l i n g c o n d i t i o n s . F u r t h e r p o s t - h o c a n a l y s i s i n d i c a t e d t h a t means f o r h i g h , medium, low shock i n t e n s i t i e s d i f f e r e d a t t o l e r a n t and con-t r o l m o deling c o n d i t i o n s . A t the i n t o l e r a n t m odeling c o n d i t i o n the h i g h l e v e l o f shock i n t e n s i t y d i f f e r e d s i g n i f i c a n t l y from t h e low and medium l e v e l s , which were . i n s i g n i f i c a n t l y d i f f e r e n t from each other,. Empathy R a t i n g s and Body A r e a R a t i n g s A n a l y s e s o f o b s e r v e r s c o r e s on the q u e s t i o n n a i r e measure o f emo-t i o n a l empathy were conducted a c c o r d i n g to a 3 x 2 ANOVA ( I n s t r u c t i o n a l C o n d i t i o n x Sex). T h i s a n a l y s i s r e v e a l e d a s i g n i f i c a n t main e f f e c t f o r Sex, _F(1,24) = 25.36, p_ < .001. E x a m i n a t i o n o f means r e v e a l e d t h a t empathy s c o r e v a l u e s were h i g h e r f o r females than f o r males (means = 65.87, 29.47, r e s p e c t i v e l y ) . R e l a t i o n s h i p s between o b s e r v e r empathy s c o r e s and o t h e r response parameters were a n a l y z e d by P e a r s o n c o r r e l a t i o n c o e f f i c i e n t s . Average v a l u e s of E _ ( d i s c r i m i n a b i l i t y ) were c a l c u l a t e d f o r each o b s e r v e r . These v a l u e s c o r r e l a t e d -.37 (_p < .05) w i t h s c o r e s on the e m o t i o n a l empathy s c a l e , w h i l e average v a l u e s of A (response b i a s ) f o r each o b s e r v e r c o r r e l a t e d .13 (n.s.) w i t h s c o r e s i n the same s c a l e . These r e s u l t s i n d i c a t e t h a t o b s e r v e r s o b t a i n i n g h i g h e s t E_ s c o r e s tended t o o b t a i n r e l a t i v e l y low e m o t i o n a l empathy s c o r e s . Observer r a t i n g s on the p o s t e x p e r i m e n t a l q u e s t i o n n a i r e e v a l u a t i n g the importance of body a r e a s were i n v e s t i g a t e d by a 3 x 2 x 10 ANOVA ( I n s t r u c t i o n a l C o n d i t i o n x Sex x Body A r e a ) . Average o r d i n a l r a t i n g s 34 a r e p r e s e n t e d i n T a b l e l a n d as can be seen from t h i s T a b l e , o b s e r v e r s i n d i c a t e d t h a t a r e a s of t h e f a c e , p a r t i c u l a r l y the eyes,.were the most i m p o r t a n t a r e a s t h a t they a t t e n d e d t o when making t h e i r r a t i n g s . 35 T a b l e 1 Average O r d i n a l R a t i n g s o f Body Areas Average. R a t i n g , Body A r e a ( c f . Waxer, 1977) 1.7 eyes 3.1 eyebrows 3.2 e y e l i d s 3.7 mouth 5.6 a n g l e o f head 5.7 f o r e h e a d 7.4 s h o u l d e r p o s t u r e 7.5 t o r s o p o s i t i o n 8.3 arm p o s i t i o n 8.9 hands 36 DISCUSSION The f i n d i n g s of t h i s study may be summarized as f o l l o w s . O b s e r v e r s were c a p a b l e of d i s c r i m i n a t i n g d i f f e r e n c e s i n the b e h a v i o u r e l i c i t e d by low, me-dium and h i g h shock l e v e l s . The a b i l i t y t o d i s c r i m i n a t e s h o c k - e l i c i t e d be-h a v i o u r was c l o s e l y r e l a t e d t o t h e magnitude o f c u r r e n t to which the sender was exposed. The d i f f e r e n c e between b e h a v i o r e l i c i t e d by h i g h l e v e l s o f shock and b e h a v i o r e l i c i t e d by medium l e v e l s o f shock was more r e a d i l y d i s c r i m i n a t e d than was the d i f f e r e n c e between b e h a v i o r e l i c i t e d by medium l e v e l s o f shock and b e h a v i o r e l i c i t e d by low l e v e l s of shock. The d i s c r i m i n a b i l i t y of shock-e l i c i t e d e x p r e s s i o n s v a r i e d s y s t e m a t i c a l l y as a f u n c t i o n o f the modeling con-d i t i o n o f the sender, w i t h the b e h a v i o r of senders exposed to a t o l e r a n t model a s s o c i a t e d w i t h the lowest v a l u e s of E_, and the b e h a v i o r of senders exposed to an i n a c t i v e c o - p a r t i c i p a n t a s s o c i a t e d w i t h the h i g h e s t E_ v a l u e s . V a r i a t i o n i n t h i s e f f e c t o c c u r r e d between the medium v s . low (ML) and the medium v s . h i g h (HM) d i s c r i m i n a t i o n , i n d i c a t i n g t h a t the r e d u c t i o n i n E_- f o r senders i n the t o l e r a n t m o d e l i n g c o n d i t i o n o c c u r r e d o n l y a t the HM d i s c r i m i n a t i o n . Males d i s c r i m i n a t e d sender b e h a v i o r more a c c u r a t e l y than d i d f e m a l e s . O b s e r v e r s r e p o r t e d o b s e r v i n g l e s s d i s t r e s s i n senders (lower A s c o r e s ) when i n s t r u c t e d t h a t senders were r e c e i v i n g d a r v o n , , r e l a t i v e t o o b s e r v e r s i n s t r u c t e d t h a t an a b r a s i v e s u r f a c e had been a d m i n i s t e r e d to the f o r e a r m of senders and r e l a t i v e t o c o n t r o l s . O b s e r v e r s r e p o r t e d l e s s sender d i s t r e s s when o b s e r v i n g the b e h a v i o r o f senders r e c e i v i n g low l e v e l s o f shock, and p a r a d o x i c a l l y , they r e p o r t e d even l e s s sender d i s t r e s s when o b s e r v i n g t h e be-h a v i o r of senders r e c e i v i n g medium l e v e l s o f shock. T h i s e f f e c t o c c u r r e d a c r o s s a l l m o d e l i n g c o n d i t i o n l e v e l s except i n the I n t o l e r a n t c o n d i t i o n where-i n low and medium d i d not d i f f e r s i g n i f i c a n t l y . O b s e r v e r s r e p o r t e d l e s s 37 sender d i s t r e s s when o b s e r v i n g the b e h a v i o r o f senders exposed to an i n t o l e r -ant model than when they o b s e r v e d controls.,and they e x h i b i t e d even lower A v a l u e s when o b s e r v i n g the b e h a v i o r o f senders exposed to a t o l e r a n t model r e -l a t i v e t o when they o b s e r v e d e i t h e r i n t o l e r a n t o r c o n t r o l s e n d e r s . V a r i a t i o n i n t h i s e f f e c t o c c u r r e d among the t h r e e l e v e l s o f shock i n t e n s i t y , i n d i c a t i n g t h a t the r e d u c t i o n i n A f o r senders i n the i n t o l e r a n t m odeling c o n d i t i o n and the f u r t h e r r e d u c t i o n i n A f o r senders i n the t o l e r a n t m odeling c o n d i t i o n o c c u r r e d o n l y a t h i g h l e v e l s o f shock. O b s e r v e r s who e x h i b i t e d good d i s c r i m i -n a t i v e performance tended t o o b t a i n r e l a t i v e l y low e m o t i o n a l empathy s c o r e s . O b s e r v e r s ' p o s t - o b s e r v a t i o n r a t i n g s i n d i c a t e d t h a t a r e a s of the f a c e , p a r t i -c u l a r l y the eyes, were the most i m p o r t a n t a r e a s t h a t they a t t e n d e d t o when making t h e i r r a t i n g s . The f a c t t h a t the HM d i s c r i m i n a t i o n was a s s o c i a t e d w i t h g r e a t e r v a l u e s of E_ than t h e ML d i s c r i m i n a t i o n r e p l i c a t e s P r k a c h i n ' s (1978) f i n d i n g s . T h i s e f f e c t was thus e f f e c t i v e l y g e n e r a l i z e d t o a l a r g e r sample o f ob s e r v e d s e n d e r s . The c u r r e n t i n t e n s i t i e s p r e s e n t e d to observed s e n d e r s were s e l e c t e d , p r i o r t o t h e i r u n d e r g o i n g e l e c t r i c shock, from 3 s u b j e c t - d e f i n e d l e v e l s : (1) t h e n o n - a v e r s i v e s e n s a t i o n t h r e s h o l d ( L ) , (2) s l i g h t l y below p a i n t h r e s h o l d (M), (3) the c l e a r l y p a i n f u l m i d p o i n t between p a i n t h r e s h o l d and p a i n t o l e r -ance (H) ( c f . , P r k a c h i n , 1978, Experiment 1 ) . Only the l a t t e r s t i m u l u s l e v e l would be expe c t e d t o r e l i a b l y e l i c i t e x p r e s s i v e r e s p o n s e s c l e a r l y i n d i c a t i v e o f p a i n . Observer E_ v a l u e s f o r the HM d i s c r i m i n a t i o n were much h i g h e r than f o r the ML d i s c r i m i n a t i o n , s u g g e s t i n g t h a t the s u p e r i o r performance was due to the o c c u r r e n c e o f e x p r e s s i v e r e s p o n s e s c l e a r l y i n d i c a t i v e o f p a i n among senders r e c e i v i n g l e v e l s of c u r r e n t i n t e n s i t y (H) p r e v i o u s l y determined to be p a i n f u l . 38 The f a c t t h a t o b s e r v e r s r e p o r t e d g r e a t e r sender d i s t r e s s ( h i g h e r A v a l u e s ) f o r senders r e c e i v i n g h i g h l e v e l s of shock s u p p o r t e d the e x p e c t a t i o n t h a t e x p r e s s i v e r e s p o n s e s i n d i c a t i v e o f p a i n would o c c u r and be o b s e r v e d more r e a d i l y a t t h i s l e v e l o f c u r r e n t i n t e n s i t y t h a n a t n o n - p a i n f u l l e v e l s . The f i n d i n g t h a t o b s e r v e r s r e p o r t e d g r e a t e r sender d i s t r e s s f o r senders r e c e i v i n g low l e v e l s of shock r e l a t i v e t o senders r e c e i v i n g medium l e v e l s o f shock p r o -v i d e s some i n t e r p r e t i v e problems. The d i f f e r e n c e s , a l t h o u g h s m a l l i n r a t i n g s c a l e v a l u e , a r e s i g n i f i c a n t f o r two m o d e l i n g c o n d i t i o n s ( t o l e r a n t and c o n t r o l ) . One p o s s i b l e e x p l a n a t i o n d e r i v e s from t h e i n c i d e n t a l a s p e c t s o f sender r e -sponse t o n o x i o u s s t i m u l a t i o n . Senders g e n e r a t e d a v a r i e t y o f b e h a v i o r ap-p a r e n t l y u n r e l a t e d t o the o c c u r r e n c e o f the e l e c t r i c shock, f o r example, chew-i n g gum, t u r n i n g the head, o r g a z i n g around t h e e x p e r i m e n t a l room. Among senders r e c e i v i n g n o n - p a i n f u l l e v e l s o f shock (Medium and Low), such i n c i d e n -t a l movements may have appeared t o o b s e r v e r s as r e l a t i v e l y major s o u r c e s of v a r i a t i o n i n sender r e s p o n s e t o t h e ' e x p e r i m e n t a l s t i m u l u s . I t was ob s e r v e d by the exp e r i m e n t e r t h a t the on s e t o f the s t i m u l u s u s u a l l y i n h i b i t e d o r t e r -minated such i n c i d e n t a l movements. Senders r e c e i v i n g p a i n f u l l e v e l s o f shock (H) g e n e r a l l y e v i d e n c e d c o n s i d e r a b l e i n h i b i t i o n of i n c i d e n t a l movement i n a d d i t i o n t o e x p r e s s i v e b e h a v i o r s more c l e a r l y i n d i c a t i v e o f p a i n . Medium l e v e l s of shock may have produced somewhat l e s s i n t e r r u p t i o n o f i n c i d e n t a l movement and low l e v e l s the l e a s t . I t may be h y p o t h e s i z e d t h a t , among medium and low l e v e l s of shocks i n the absence o f c l e a r i n d i c a t i o n s of p a i n , o b s e r v -e r s may have m i s t a k e n l y i n t e r p r e t e d g r e a t e r r e s i d u a l amounts of i n c i d e n t a l movement as i n d i c a t i v e o f more p a i n , and thus r e p o r t e d more d i s t r e s s , f:or senders r e c e i v i n g low l e v e l s o f shock r e l a t i v e t o medium l e v e l s . T h i s e x p l a -n a t i o n c o u l d be t e s t e d by r a t i n g senders on amount of movement ( i n c i d e n t a l o r o t h e r w i s e ) , t h e n examining t h e c o r r e s p o n d e n c e between o b s e r v e r r e p o r t s of 39 sender movement and sender d i s c o m f o r t . A second p o s s i b l e i n t e r p r e t a t i o n d e r i v e s from the o b s e r v a t i o n t h a t s e n d e r s r e c e i v i n g low l e v e l s o f shock appeared more f r e q u e n t l y to e x h i b i t an e x p r e s s i o n of i n t e n s e c o n c e n t r a t i o n w h i l e a t t e m p t i n g to d i s c e r n the p r e -sence or absence o f the b a r e l y d e t e c t a b l e ( t h r e s h o l d ) s t i m u l u s . Such an ex-p r e s s i o n b e a r s a resemblance to someone i n d i s t r e s s and c o u l d have produced a r t i f a c t u a l e l e v a t i o n s i n r a t i n g s . The f a c t t h a t o b s e r v e r s r e p o r t e d l e a s t d i s t r e s s (lower A v a l u e s ) when o b s e r v i n g the b e h a v i o r of senders exposed to a t o l e r a n t model and most d i s t r e s s when o b s e r v i n g s e n d e r s exposed to an i n -a c t i v e c o - p a r t i c i p a n t i n d i c a t e s t h a t b o t h a c t i v e m odeling i n f e r e n c e s ( e s -p e c i a l l y the t o l e r a n t model) produced d i s c e r n i b l e r e d u c t i o n s i n e x p r e s s i v e r e -a c t i o n to n o x i o u s s t i m u l a t i o n . E p l e y ' s (1974, p. 273) o b s e r v a t i o n t h a t "a companion t h a t emits calm r e s p o n s e s i n a t h r e a t e n i n g s i t u a t i o n may e l i c i t s i m i l a r b e h a v i o r s from the o b s e r v i n g s u b j e c t " i s s u p p o r t e d i n t h a t b o t h the t o l e r a n t and i n t o l e r a n t model made r a t i n g s i n an e x p r e s s i v e s t y l e t h a t was q u i t e d i s p a s s i o n a t e (independent of the a c t u a l c o n t e n t of t h e i r r a t i n g s ) and b o t h produced r e d u c t i o n s i n p a i n d i s p l a y of s e n d e r s . The i n a c t i v e c o - p a r t i c i -pant made no e x p r e s s i v e communication, thus m i n i m i z i n g any c a l m i n g i n f l u e n c e t h a t might a r i s e t h r o u g h the e x p r e s s i v e s t y l e of a companion. R e l i a b l e d i f f e r e n c e s i n t h e d i s c r i m i n a b i l i t y o f s h o c k - e l i c i t e d e x p r e s s i o n s were o b t a i n e d as a f u n c t i o n o f the m odeling c o n d i t i o n of the sender, f o r d i s -c r i m i n a t i o n s i n v o l v i n g noxious l e v e l s o f s t i m u l a t i o n . The b e h a v i o r of senders exposed to a t o l e r a n t model was l e s s d i s c r i m i n a b l e than the b e h a v i o r o f send-e r s i n b o t h of the o t h e r groups. In c o n t r a s t to P r k a c h i n ' s (1978) s t u d y , however, o n l y th e b e h a v i o r of senders exposed to a t o l e r a n t model was s i g n i -f i c a n t l y l e s s d i s c r i m i n a b l e than t h a t of c o n t r o l ' s u b j e c t s . In P r k a c h i n ' s ex-p e r iment, which used s i m i l a r s t i m u l u s m a t e r i a l s , a s i m i l a r p a t t e r n of f i n d i n g s 40 emerged, w i t h t h e b e h a v i o r o f s e n d e r s exposed to a t o l e r a n t model b e i n g l e s s d i s c r i m i n a b l e than t h a t o f s u b j e c t s exposed to an i n t o l e r a n t model o r c o n t r o l s . The b e h a v i o r o f s u b j e c t s exposed to an i n t o l e r a n t model was a l s o l e s s d i s c r i m i n a b l e than t h a t o f c o n t r o l s u b j e c t s . I t i s l i k e l y t h a t the s o u r c e o f t h i s d i s c r e p a n c y l i e s i n the manner i n which e x c e r p t s of b e h a v i o r were chosen f o r v i e w i n g by o b s e r v e r s i n the two s t u d i e s . I n P r k a c h i n ' s s t u d y , o b s e r v e r s viewed fewer senders but f o r longer' p e r i o d s of time. I n the p r e -s e n t s t u d y , o b s e r v e r s viewed o n l y the f i r s t two examples of sender b e h a v i o r at each of th e t h r e e l e v e l s o f shock i n t e n s i t y f o r 30 s u b j e c t s . F o r the f o r e -g o i n g r e a s o n i t can be concludedofrom the p r e s e n t s t u d y t h a t the impact of exposure to a t o l e r a n t model on p a i n d i s p l a y s of senders i s r e l a t i v e l y power-f u l and immediate. The r e d u c t i o n s i n p a i n d i s p l a y s f o r senders exposed to an i n t o l e r a n t model a p p a r e n t l y o c c u r r e d l e s s r a p i d l y t h a n d i d r e d u c t i o n s i n p a i n d i s p l a y s f o r senders exposed to t o l e r a n t models. The r e l a t i v e d e l a y i n the e f f e c t i v e n e s s o f exposure t o an i n t o l e r a n t model i n r e d u c i n g p a i n d i s p l a y s may imply t h a t t h e i n t o l e r a n t and t o l e r a n t m o d e l i n g i n f l u e n c e s may have e l i c i t e d d i f f e r e n t p r o c e s s e s i n s e n d e r s exposed to them. While b o t h models may have e x e r t e d a c a l m i n g e f f e c t on senders ( E p l e y , 1974), i t i s p o s s i b l e t h a t h i g h e r s u b j e c t i v e p a i n r a t i n g s g i v e n by the i n t o l e r a n t model e x e r t e d an e f f e c t on senders t h a t was superimposed upon the c a l m i n g e f f e c t . The n u m e r i c a l e s t i -mate i n f o r m a t i o n p r o v i d e d by the i n t o l e r a n t model, w h i l e s a l i e n t d u r i n g t h e i n i t i a l s t a g e s of the shock s e r i e s , may have d i m i n i s h e d i n importance a f t e r s e v e r a l exposures t o the shock, as the sender became aware of the c o m p e l l i n g f a c t o f the i n t o l e r a n t model's d i s p a s s i o n a t e demeanor. The d i f f e r e n c e s i n e x p r e s s i v e r e s p o n s e produced by m o d e l i n g i n f l u e n c e s may have i m p o r t a n t r e l a t i o n s h i p s t o o t h e r a s p e c t s of the e x p e r i e n c e of p a i n . 41 I n a s e r i e s of s t u d i e s , K l e c k , L a n z e t t a , and t h e i r c o l l e a g u e s have m a r s h a l l e d e v i d e n c e c o n s i s t e n t w i t h the n o t i o n t h a t the e x p e r i e n c e of p a i n may be d i r e c t l y modulated by o v e r t e x p r e s s i v e b e h a v i o r . I n t h r e e experiments de-s i g n e d t o e x p l o r e the r e l a t i o n s h i p between e x p r e s s i v e b e h a v i o r and the i n -t e n s i t y o f e m o t i o n a l a r o u s a l , L a n z e t t a , C a r t w r i g h t - S m i t h & K l e c k (1976) asked s u b j e c t s e i t h e r t o exaggerate, o r to c o n c e a l the f a c i a l d i s p l a y a s s o c i a t e d w i t h the a n t i c i p a t i o n and r e c e p t i o n o f p a i n f u l shocks t h a t v a r i e d i n i n t e n s i t y , i n o r d e r to examine the e f f e c t s o f augmentation and r e d u c t i o n of f a c i a l e x p r e s -s i o n on s e l f - r e p o r t s "of p a i n and s k i n conductance measures o f a r o u s a l . R e s u l t s i n d i c a t e d p a r a l l e l changes i n both i n d i c e s among s u b j e c t s i n s t r u c t e d t o a l t e r f a c i a l r e s p o n s e s . Both the magnitude of s k i n conductance r e s p o n s e s and s e l f - r e p o r t s of d i s c o m f o r t were lower d u r i n g pose-no shock t r i a l s compared to p o s e - i n t e n s e - s h o c k t r i a l s . The a u t h o r s a c c o u n t e d f o r t h e s e f i n d i n g s by p r o -p o s i n g t h a t s u b j e c t s may have responded to the r e q u e s t t o pose f a c i a l e x p r e s -s i o n s by r e a p p r a i s i n g the p a i n f u l n e s s o f the shock i n o r d e r to make t h e i r ex-p r e s s i o n s appear a u t h e n t i c . T h i s c o g n i t i v e r e a p p r a i s a l was s u g g e s t e d to have reduced or augmented the a c t u a l l e v e l o f s t r e s s . I n an e x t e n s i o n o f t h i s paradigm, K l e c k , Vaughan, C a r t w r i g h t - S m i t h , Vaughan, C o l b y , and L a n z e t t a (1976) examined the e f f e c t s of the p r e s e n c e of an o b s e r v e r on e x p r e s s i v e r e s p o n s e s to p a i n f u l s t i m u l i and on s u b j e c t i v e and au-tonomic r e a c t i o n s . S u b j e c t s who were l e d to b e l i e v e they were b e i n g o b s e r v e d b e h i n d a one-way window e v i d e n c e d a t t e n u a t e d e x p r e s s i v e r e s p o n s e s t o shock, accompanied by a g e n e r a l d e c r e a s e i n s u b j e c t i v e p a i n r e p o r t s and autonomic r e -sponses to the n o x i o u s s t i m u l i . The a u t h o r s e x p l a i n e d the c o v a r i a n c e of ex-p r e s s i v e and s u b j e c t i v e i n d i c e s of p a i n i n terms of c l a s s i c a l c o n d i t i o n i n g . E x p r e s s i v e r e s p o n s e s as w e l l as autonomic a c t i v i t y were c o n c e i v e d as u n c o n d i -42 t i o n e d r e s p o n s e s to e m o t i o n a l l y a r o u s i n g s t i m u l i . By t a k i n g the t e m p o r a l r e l a t i o n s h i p s between the two s e t s of r e s p o n s e s i n t o a c c o u n t , i t was sug-g e s t e d t h a t the former i n v a r i a b l y p r e c e d e , and o f t e n o v e r l a p , the l a t t e r r e s p o n s e s . Thus e x p r e s s i v e cues may come to f u n c t i o n as c o n d i t i o n e d s t i m u l i f o r autonomic r e s p o n s e s . E x p r e s s i v e cues and autonomic r e s p o n s e s may be con-c e p t u a l i z e d as i n t e r a c t i n g w i t h the u n c o n d i t i o n e d s t i m u l u s , so t h a t changes i n one component o f the i n t e r a c t i o n may produce p a r a l l e l changes i n one or b o t h of the o t h e r s . C o l b y , L a n z e t t a , & K l e c k (1977) i n s t r u c t e d s u b j e c t s to adopt f a c i a l ex-p r e s s i o n s of p a i n of v a r i o u s i n t e n s i t i e s under c o n d i t i o n s i n which they t e r -minated i n c r e a s i n g l y i n t e n s e e l e c t r i c shocks a t t h e i r t o l e r a n c e l e v e l . T h i s p r o c e d u r e was i n s t i t u t e d t o i n v e s t i g a t e whether o v e r t l y i n s t r u m e n t a l r e s p o n -ses r e l a t e d to p a i n , i n a d d i t i o n to s u b j e c t i v e and autonomic r e s p o n s e s , a r e s u b j e c t to m o d u l a t i o n v i a f a c i a l e x p r e s s i o n . A l t h o u g h the e f f e c t o f p o s i n g on l e v e l o f shock t o l e r a t e d by s u b j e c t s was not s i g n i f i c a n t , the p r e v i o u s l y o b t a i n e d c o r r e s p o n d e n c e between f a c i a l e x p r e s s i o n . a n d s k i n conductance was o b s e r v e d . S u b j e c t s i n one c o n d i t i o n o f the s t u d y were p r o v i d e d w i t h d i r e c t c o n t r o l over the s t r e s s o r , thus o b v i a t i n g the p o t e n t i a l i n s t r u m e n t a l v a l u e of f a c i a l e x p r e s s i o n i n t e r m i n a t i n g the p a i n . The l i n k between f a c i a l ex-p r e s s i o n and s k i n conductance remained however, l e a d i n g the a u t h o r s to sug-g e s t t h a t f a c i a l f eedback e f f e c t s a r e not l i m i t e d t o c o n d i t i o n s i n which ex-p r e s s i o n s may p l a y a communicative o r i n s t r u m e n t a l f u n c t i o n . A l t h o u g h the s p e c i f i c mechanisms r e s p o n s i b l e f o r the c o v a r i a n c e o f ex-p r e s s i v e and s u b j e c t i v e i n d i c e s o f p a i n a r e not c l e a r , the c l a s s i c a l c o n d i -t i o n i n g e x p l a n a t i o n o f f e r e d by K l e c k e_t a l . (1976) may p rove f r u i t f u l : , i n i t s c o n c e p t i o n of e x p r e s s i v e b e h a v i o r working i n r e c i p r o c a l i n f l u e n c e w i t h sub-j e c t i v e and autonomic r e s p o n s e s to p o t e n t i a l l y p a i n f u l s t i m u l i . Such a view 43 r e f l e c t s . r e c e n t c o n c e p t i o n s o f the cause of b e h a v i o r i n which b e h a v i o r i s no l o n g e r c o n s i d e r e d t o be a b y - p r o d u c t of i n t e r d e p e n d e n t p e r s o n s and s i t u a t i o n s , but i s r e c o g n i z e d as an i n t e r l o c k i n g d e t e r m i n a n t i n the c a u s a l p r o c e s s (Bandura, 1978). The i n s t r u c t i o n s d e s i g n e d to i n c r e a s e r e p o r t s of observed p a i n were r e -l a t i v e l y e f f e c t i v e i n e l e v a t i n g r e p o r t s of observed p a i n w h i l e those d e s i g n e d to d e c r e a s e r e p o r t s of observed p a i n were r e l a t i v e l y i n e f f e c t i v e i n p r o d u c i n g such d e c r e a s e s . Thus, p r o v i d i n g o b s e r v e r s w i t h p a i n - r e l e v a n t i n f o r m a t i o n p r i o r t o o b s e r v i n g senders was e f f e c t i v e i n a l t e r i n g r e p o r t s of o b s e r v e d p a i n w i t h -out a l t e r i n g the d i s c r i m i n a b i l i t y o f p a i n b e h a v i o r . The r e l a t i v e i n e f f e c t i v e -ness of the darvon i n s t r u c t i o n s i s not c l a r i f i e d by o b s e r v e r r e s p o n s e s to t h e d e b r i e f i n g q u e s t i o n n a i r e (Appendix B ) . On a s c a l e where 1 was v e r y much so and 5, not a t a l l , o b s e r v e r s gave the darvon and sandpaper t r e a t m e n t s mean r a t i n g s of 2.4 and 2.7, r e s p e c t i v e l y as making a d i f f e r e n c e to the s e n d e r s ' e x p e r i e n c e o f p a i n . In r e s p o n s e to the q u e s t i o n n a i r e i t e m a s k i n g whether know-l e d g e of the treatment a f f e c t e d t h e i r r a t i n g s , 44% of the o b s e r v e r s r e c e i v i n g d a r von and 30%...of .observers, r e c e i v i n g sandpaper i n s t r u c t i o n s responded a f f i r m a -t i v e l y . The i n e f f e c t i v e n e s s o f the darvon i n s t r u c t i o n s i n i n f l u e n c i n g p a i n r e p o r t s downward may i n d i c a t e t h e o p e r a t i o n of a k i n d of basement e f f e c t . Sender ex-p r e s s i v e d i s p l a y s produced an average r a t i n g by u n i n f l u e n c e d o b s e r v e r s of 2.963 on the 7 - p o i n t s c a l e . T h i s number c o r r e s p o n d s a p p r o x i m a t e l y to the t h i r d l owest s c a l e c a t e g o r y , n o n - p a i n s e n s a t i o n . The f o u r t h lowest s c a l e c a -t e g o r y (very f a i n t p a i n ) i s , by d e f i n i t i o n , the t h r e s h o l d f o r p a i n o b s e r v a t i o n . The average o b s e r v e r r a t i n g of 2.963 i n d i c a t e s t h a t the m a j o r i t y of sender r e s p o n s e s were r a t e d as below t h i s t h r e s h o l d . Thus i t may be t h a t the darvon 44 i n s t r u c t i o n s were i n e f f e c t i v e i n r e d u c i n g o b s e r v e r r e p o r t s of sender p a i n because o b s e r v e r s weire a l r e a d y r e p o r t i n g v e r y l i t t l e p a i n . The e f f e c t i v e n e s s of the sandpaper i n s t r u c t i o n s i s i n t e r e s t i n g i n l i g h t o f numerous i n c i d e n t a l o b s e r v e r comments which s u g g e s t e d t h a t o b s e r v e r s i n the sandpaper group be-l i e v e d t h i s t r e a t m e n t to be l e s s e f f e c t i v e due to the g e n e r a l l y low l e v e l of d i s t r e s s they p e r c e i v e d i n o b s e r v e d senders subsequent t o b e i n g i n f o r m e d o f the h i g h l y p a i n f u l sounding e x p e r i e n c e t o which they had been exposed. Ap-p a r e n t l y t h e p r i o r b i a s i n g i n f o r m a t i o n e x e r t e d an e f f e c t on o b s e r v e r r a t i n g s d e s p i t e c o n s i d e r a b l e doubt as to i t s e f f e c t i v e n e s s . T h i s s u g g e s t s t h a t ob-s e r v e r w i l l i n g n e s s t o r e p o r t p a i n can be i n f l u e n c e d i n d e p e n d e n t l y o f d i r e c t e v i d e n c e of. p a i n . 45 The f i n d i n g t h a t p r i o r p a i n - r e l e v a n t i n f o r m a t i o n i s e f f e c t i v e i n a l t e r i n g r e p o r t s of o b s e r v e d p a i n i s an i m p o r t a n t one. The importance and v a l i d i t y o f t h i s phenomenon would i n c r e a s e w i t h a d e m o n s t r a t i o n t h a t a l t e r e d b i a s e s have f u r t h e r b e h a v i o r a l consequences f o r o b s e r v e r s of p a i n . I t would be p o s s i b l e t o p r o v i d e o b s e r v e r s w i t h an o p p o r t u n i t y to demon-s t r a t e o v e r t c a r e t a k i n g r e s p o n s e s to persons i n d i s t r e s s by means of a d e s i g n whereby o b s e r v e r s would r e c e i v e b i a s i n g p a i n - r e l e v a n t i n f o r m a t i o n , t h e n would r a t e a sender's e x p r e s s i v e b e h a v i o r , as i n the p r e s e n t s t u d y , w i t h the f o l l o w i n g m o d i f i c a t i o n s . F i r s t , t h e o b s e r v e r would a c t u a l l y be p r e s e n t d u r i n g the a d m i n i s t r a -t i o n o f t h e shock; second, t h e o b s e r v e r would make r a t i n g s on paper, r a t h e r than a l o u d ; t h i r d , the o b s e r v e r would be r e q u e s t e d to a s s i s t i n e n s u r i n g t h e comfort of th e p e r s o n r e c e i v i n g the s h o c k s , and so would be i n s t r u c t e d to engage i n one of a v a r i e t y of c a r e t a k i n g r e s p o n s e s f o l l o w i n g each r a t i n g . F o r example, i f a 7 - p o i n t s c a l e were employed by o b s e r v e r s , where 1 i s UNDETECTABLE SENSATION, 7 i s STRONG PAIN, and 4 i s VERY FAINT PAIN, o b s e r v e r s would be i n s t r u c t e d to r a t e the amount of p a i n o b s e r v e d f o r each p r e s e n t a t i o n of shock t o the s e n d e r . A d d i t i o n a l l y , they would be i n f o r m e d of t h e i r o p t i o n t o communicate, a f t e r any t r i a l s " a message of s u c c o r to the sender, such as a r e q u e s t as to how the sender was f e e l i n g , o r a reminder of the sender's r i g h t t o t e r m i n a t e the s e s s i o n a t any t i m e . I t would thus be p o s s i b l e to i n v e s t i g a t e the e f f e c t o f p r i o r p a i n -r e l e v a n t i n f o r m a t i o n i n a l t e r i n g not o n l y r e p o r t s o f o b served p a i n , but a l s o o v e r t b e h a v i o r a l r e s p o n s e s to p a i n d i s p l a y s . Of note i s the a d d i t i o n -a l f a c t t h a t o b s e r v e r s ' c a r e t a k i n g r e s p o n s e s would be made d i r e c t l y t o shocked s e n d e r s , e n a b l i n g i n v e s t i g a t i o n of p o s s i b l e s h a p i n g i n f l u e n c e s of •46 the c a r e t a k i n g r e s p o n s e s on sender judgments o f c u r r e n t i n t e n s i t y . A l -though d e t a i l s o f t h i s example a r e not complete, i t s u g g e s t s a d e s i g n t h a t might c l a r i f y n a t u r a l l y - o c c u r r i n g p r o c e s s e s o f mutual i n f l u e n c e between p a i n s u f f e r e r and c a r e t a k e r . •The f i n d i n g t h a t o b s e r v e r s who o b t a i n e d h i g h e s t d i s c r i m i n a b i l i t y s c o r e s tended t o o b t a i n r e l a t i v e l y low e m o t i o n a l empathy s c o r e s r e q u i r e s some d i s c u s s i o n . I n reviews of r e s e a r c h on empathy, Mehrabian & E p s t e i n (1972) no t e two d i f f e r e n t approaches t o empathy. The f i r s t i s r e p r e s e n t e d by Dymond's (1949) c o g n i t i v e r o l e - t a k i n g approach; an empathic p e r s o n i s s a i d t o i m a g i n a t i v e l y t a k e the r o l e o f another and can u n d e r s t a n d and p r e -d i c t t h a t person's t h o u g h t s , f e e l i n g s , and a c t i o n s . I n t h i s c o n t e x t , the n e u t r a l i t y and detachment o f the em p a t h i z i n g p e r s o n was viewed as a i d i n g a c c u r a c y (e.g., Rogers, 1957). The second approach d e f i n e d empathy as a v i c a r i o u s e m o t i o n a l r e s p o n s e t o the p e r c e i v e d e m o t i o n a l e x p e r i e n c e s of o t h e r s . The c r i t i c a l d i f f e r e n c e i s t h a t c o g n i t i v e r o l e - t a k i n g i s the r e c o g -n i t i o n o f a n o t h e r ' s f e e l i n g s , whereas empathic e m o t i o n a l r e s p o n s i v e n e s s i n -c l u d e s s h a r i n g of those f e e l i n g s , a t l e a s t a t the g r o s s a f f e c t ( p l e a s a n t -u n p l e a s a n t ) l e v e l . S c o r e s on Mehrabian & E p s t e i n ' s empathy s c a l e r e f l e c t the second d e f i n i t i o n o f empathy. The s i g n i f i c a n t n e g a t i v e i - c o r r e l a t i o n between empathy s c a l e s c o r e s and o b s e r v e r s ' d i s c r i m i n a t i o n s c o r e s has some i n t e r e s t i n g t h e o r e t i c a l i m p l i c a t i o n s . The n o t i o n t h a t empathic p r o c e s s e s a r e c r i t i c a l c o n d i t i o n s . f o r s u c c e s s f u l p s y c h o t h e r a p y i s a fundamental p r o -p o s i t i o n o f c l i e n t - c e n t e r e d t h e r a p y (Rogers, 1957), and i s a w i d e l y h e l d b e l i e f among c l i n i c i a n s and r e s e a r c h e r s a l i k e . Mehrabian and E p s t e i n (1972), among o t h e r s , have s u g g e s t e d t h a t h i g h l e v e l s o f e m o t i o n a l empathy may p r e d i c t s u c c e s s o f b e g i n n i n g t h e r a p i s t s . Taken a t f a c e v a l u e , the r e -l a t i o n s h i p d i s c o v e r e d i n t h e p r e s e n t study s u g g e s t s a more c a u t i o u s 47 a t t i t u d e toward such s p e c u l a t i o n . O b s e r v e r s who o b t a i n e d h i g h empathy s c o r e s tended to be poor o b s e r v e r s of b e h a v i o r . Assuming t h e v a l i d i t y o f t h i s r e l a t i o n s h i p , a t l e a s t two p o s s i b l e i n t e r p r e t a t i o n s havingr-tele-cs-vance to t h e r a p e u t i c p r o c e s s e s can be o f f e r e d . One i s t h a t e f f e c t i v e t h e r a -p e u t i c change o c c u r s when a t h e r a p i s t behaves i n an e m o t i o n a l l y empathic manner, and t h a t s k i l l i n o b s e r v i n g the b e h a v i o r of another i s i r r e l e v a n t t o t h e r a p e u t i c change. A l t e r n a t i v e l y , , i f i t i s a c c e p t e d t h a t e f f e c t i v e t h e r a p y r e q u i r e s a c c u r a t e o b s e r v a t i o n of b e h a v i o r on the p a r t of the t h e r a -p i s t , i t may be t h a t employing t h e r a p i s t s who a r e n a t u r a l l y empathic, o r t r a i n i n g t h e r a p i s t s i n empathy, f o c u s e s on a f a c t o r t h a t makes f o r i n e f f e c t -i v e t h e r a p y . S t r o n g sex d i f f e r e n c e s i n s c o r e s on the empathy s c a l e and i n d i s c r i m i -n a t i v e performance were o b s e r v e d : men o b t a i n e d much lower e m o t i o n a l empa-thy s c o r e s (X = 29.47) than women (X = 65.87) and h i g h e r E_ s c o r e s (means 0.232 and 0.151, f o r males and f e m a l e s , r e s p e c t i v e l y ) . I n the p r e s e n t s t u d y , use of SDT methodology a l l o w e d the s e p a r a t i o n of two components of o b s e r v e r s ' r e s p o n s e to e v i d e n c e of p a i n i n o t h e r s : a b i l i t y t o d i s c r i m i n a t e d i f f e r e n c e s i n s ' h o c k - e l i c i t e d e x p r e s s i o n s and t e n -dency t o r e p o r t the p r e s e n c e of p a i n . The f i n d i n g . t h a t i n s t r u c t i o n a l mani-p u l a t i o n s were c a p a b l e of a f f e c t i n g the second component has potential:., i m p l i c a t i o n s beyond the e x p e r i m e n t a l s e t t i n g employed i n t h i s s t u d y . The . t a s k u n d e r t a k e n by o b s e r v e r s i n t h i s study was r o u g h l y analogous to the type o f a c t i v i t y engaged i n by p h y s i c i a n s a t t e m p t i n g to a s s e s s the magni-tude of p a i n e x p e r i e n c e d by p a t i e n t s . 48 The p r e s e n t f i n d i n g s i n d i c a t e t h a t i n f o r m a t i o n about a p a t i e n t ' s t reatment may be an e f f e c t i v e d e t e r m i n a n t o f a d i a g n o s t i c i a n ' s c r i t e r i o n f o r a c c e p t i n g a p a r t i c u l a r s e t o f e v i d e n c e as i n d i c a t i v e o f p a i n . A g r e a t number of v a r i a b l e s have the p o t e n t i a l to i n f l u e n c e the d e c i s i o n s o f d i a g n o s t i c i a n s i n the n a t u r a l s e t t i n g . The e f f e c t i v e n e s s o f i n f o r m a t i o n about a p a t i e n t ' s p e r s o n a l c h a r a c t e r i s t i c s , the h i s t o r y o f the problem, i t s r e s p o n s e to t r e a t m e n t , t h e p r e s e n c e of p s y c h i a t r i c d i s t u r b a n c e , and the p a t i e n t ' s e t h n i c i t y , may prove o f d i f f e r e n t i a l i mportance i n p a i n d i a g n o s i s . T h e o r e t i c a l l y , . , t h e s i g n a l d e t e c t i o n parameters o f d i s c r i m i n a b i l i t y and b i a s a r e c o n c e i v e d t o be independent of one a n o t h e r . F a c t o r s t h a t produce a l t e r a t i o n s i n one index need n o t have any e f f e c t on the o t h e r t h a t can be s p e c i f i e d a. p r i o r i . C l a r k (1974) has e m p i r i c a l l y demonstrated such independence w i t h r e s p e c t t o d i r e c t p s y c h o p h y s i c a l judgments by s u b j e c t s u n d e r g o i n g p a i n f u l e x p e r i e n c e . The f a c t t h a t the i n s t r u c t i o n a l m a n i p u l a -t i o n s employed i n t h e p r e s e n t study e x e r t e d t h e i r e f f e c t e x c l u s i v e l y on the measure o f b i a s and had no impact on the measure o f d i s c r i m i n a t i o n i s , of c o u r s e , c o n s i s t e n t w i t h the common b e l i e f t h a t i n s t r u c t i o n a l m a n i p u l a -t i o n s a f f e c t o n l y d e c i s i o n - m a k i n g p r o c e s s e s . I t i s p o s s i b l e , however, t h a t c e r t a i n p a i n - r e l e v a n t i n f o r m a t i o n c o u l d i n d u c e a l t e r a t i o n s i n b o t h the tendency o f a d i a g n o s t i c i a n t o a c c e p t b e h a v i o r a l e v i d e n c e as i n d i c a t i v e o f p a i n , and i n the a c c u r a c y o f the d i a g n o s t i c i a n s ' judgments. F o r example, i n the n a t u r a l s e t t i n g , p r i o r i n f o r m a t i o n r e g a r d -i n g a number of c h a r a c t e r i s t i c s might a f f e c t d i a g n o s t i c a c c u r a c y by way of i n f l u e n c i n g f a c t o r s such as w i l l i n g n e s s t o spend s u f f i c i e n t time w i t h a p a t i e n t i n o r d e r t o o b s e r v e an adequate sample o f h i s / h e r b e h a v i o r , or 49 closeness of a t t e n t i o n to d e t a i l s of a patient's behavior i n a r r i v i n g at a decision. Consider a hypothetical example i n which diagnosticians are required to evaluate the severity of two groups of patients' pain expressions i n r e l a t i o n to some category scale. Assume that p r i o r c a l c u l a t i o n of d i s c r i -m i n a b i l i t y scores of two groups of diagnosticians reveals exactly equal values (e.g., E_ = 1.0) for the two groups of patients. Another two groups of diagnosticians are now-: presented with the same pain expressions, except that t h i s time, one group i s t o l d that the patients are a l l I t a l i a n , whereas the second group i s t o l d that the patients have p s y c h i a t r i c problems and are obsessive neurotics. Conceivably, both types of information could induce s i m i l a r biases against diagnosing severe pain i n both patient groups. For example, what was formerly judged as severe pain might now be accepted as evidence f o r mild pain. This would be revealed as a c r i t e r i o n s h i f t when SDT parameters were ca l c u l a t e d . However, the presence of biasing i n -formation might a d d i t i o n a l l y a f f e c t processes underlying diagnostic accuracy as w e l l . For example, i f the information that the patient was I t a l i a n tended to make diagnosticians r e l a t i v e l y l e s s a t t e n t i v e to the patient's behavior and l e s s w i l l i n g to spend s u f f i c i e n t time before a r r i v i n g at a dec i s i o n , the accuracy of the judgment could be v i t i a t e d . I f , on the other hand, the information that the patient was obsessive induced a r e l a t i v e l y close scrutiny of h i s behavior and a more thorough examination than for a non-obsessive patient, judgment accuracy could be enhanced. I t can be seen how a d i f f e r e n c e i n closeness of attention and time spent making a judgment could a f f e c t h i t and f a l s e alarm rates i n a s i g n a l detection task. For t h i s hypothetical case, subsequent c a l c u l a t i o n of judgment accuracy scores 50 on the d e c i s i o n s g e n e r a t e d by each group o f p h y s i c i a n s under the i n f l u e n c e o f one o f t h e two types of b i a s i n g i n f o r m a t i o n c o n c e i v a b l y c o u l d r e v e a l t h a t the p h y s i c i a n s i n f o r m e d t h a t the p a t i e n t was I t a l i a n e v i d e n c e d a v e r -age E s c o r e s o f 0.7 w h i l e t h o s e i n f o r m e d t h a t the p a t i e n t was o b s e s s i v e e v i d e n c e average E s c o r e s of 1.2. In t h i s example, b o t h types of b i a s i n g i n f o r m a t i o n c o u l d be e q u a l l y e f f e c t i v e i n a l t e r i n g the p h y s i c i a n s ' tendency to a c c e p t a p a r t i c u l a r s e t of e v i d e n c e as i n d i c a t i v e o f p a i n . However, one ty p e ( e t h n i c i n f o r m a t i o n ) produced a d e c r e a s e i n d i a g n o s t i c a c c u r a c y (E went from 1.0 to 0.7) w h i l e the o t h e r type ( p s y c h i a t r i c i n f o r m a t i o n ) produced an i n c r e a s e i n d i a g n o s t i c a c c u r a c y (E went from 1.0 t o 1.2). V a r i o u s types o f p a i n - r e l e v a n t i n f o r m a -t i o n c o u l d be e v a l u a t e d i n t h i s way as b e i n g p o t e n t i a l l y v a l u a b l e , u s e l e s s , or even d e t r i m e n t a l to d i a g n o s t i c d e c i s i o n - m a k i n g . Subsequent i d e n t i f i c a -t i o n o f the i n f l u e n c e on s p e c i f i c f a c t o r s d e t e r m i n i n g judgment a c c u r a c y of b i a s i n g i n f o r m a t i o n c o u l d s t i m u l a t e r e s e a r c h i n t o p r o c e s s e s u n d e r l y i n g a c c u r -a t e d i a g n o s t i c d e c i s i o n - m a k i n g , and p o s s i b l y r e s u l t i n i n c r e a s e s i n a c c u r a c y . 51 REFERENCES Adams, C., H a l l , D., Pennypacker, H., G o l d s t e i n , M., Hench, L., Madden, M., S t e i n , G., & C a t a n i a , A. Lump d e t e c t i o n i n s i m u l a t e d human b r e a s t s . P e r c e p t i o n & P s y c h o p h y s i c s , 1976, 20_, 163-167. A r c h e r , D., & A k e r t , . R.M. Words and e v e r y t h i n g e l s e : V e r b a l and n o n v e r b a l cues i n s o c i a l i n t e r p r e t a t 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 P s y c h o l o g y , 1977, 86, 224-234. 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P e r c e p t u a l and Motor S k i l l s , 1972, 34, 943-944. Dymond, R.F. A s c a l e f o r measurement of empathic a b i l i t y . J o u r n a l o f  C o n s u l t i n g P s y c h o l o g y , 1949, 14, 127-133. Ekman, P., & F r i e s e n , W.V. N o n v e r b a l l e a k a g e and c l u e s t o d e c e p t i o n . P s y c h i a t r y , 1969, 32, 88-106. Ekman, P., & F r i e s e n , W.V. D e t e c t i n g d e c e p t i o n from the body or f a c 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 P s y c h o l o g y , 1974, 29, 288-298. E p l e y , S.Wo R e d u c t i o n of the b e h a v i o r a l e f f e c t s o f a v e r s i v e s t i m u l i by the p r e s e n c e o f companions. P s y c h o l o g i c a l B u l l e t i n , 1974, _81, 271-283. F e a t h e r , B.W., Chapman, C.F., & F i s h e r , S.B. The e f f e c t of a p l a c e b o on the p e r c e p t i o n o f p a i n f u l r a d i a n t heat s t i m u l i . P s y c h o s o m a t i c M e d i c i n e , 1972, 34, 270-294. For d y c e , W.E. B e h a v i o r a l methods f o r c h r o n i c p a i n and i l l n e s s . S t . L o u i s : C.V. Mosby, 1976. Green, D.M., & Swets, J.A. S i g n a l d e t e c t i o n t h e o r y and p s y c h o p h y s i c s . New York: W i l e y , 1966. 54 G r o s s b e r g , J.M. , & Grant, B.F. C l i n i c a l p s y c h o p h y s i c s : A p p l i c a t i o n s of r a t i o s c a l i n g and s i g n a l d e t e c t i o n methods to r e s e a r c h on p a i n , f e a r , d rugs, and m e d i c a l d e c i s i o n making. P s y c h o l o g i c a l B u l l e t i n , 1978, 85_, 1154-1176. H i l g a r d , E.R. P a i n as a p u z z l e f o r p s y c h o l o g y and p h y s i o l o g y . American P s y c h o l o g i s t , 1969, 24> 103-113. K l e c k , R.E., Vaughan, R.C., C a r t w r i g h t - S m i t h , J . , Vaugan, K.B., C o l b y , C.Z., & L a n z e t t a , J.T. E f f e c t s of b e i n g observed on e x p r e s s i v e , s u b j e c t i v e , and p h y s i o l o g i c a l r e s p o n s e s t o p a i n f u l s t i m u l i . J o u r n a l o f P e r s o n a l i t y and S o c i a l P s y c h o l o g y , 1976, 34, 1211-1218. K r a u t , R.E. V e r b a l and n o n v e r b a l cues i n the p e r c e p t i o n o f l y i n g . 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 P s y c h o l o g y , 1978, 36. 380-391. L a n z e t t a , J.T., C a r t w r i g h t - S m i t h , J . , & K l e c k , R.E. E f f e c t s of n o n v e r b a l d i s s i m u l a t i o n on e m o t i o n a l e x p e r i e n c e and autonomic a r o u s a l . 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 P s y c h o l o g y , 1976, _ 3 , 354-370. L i e b e s k i n d , J.C., & P a u l , L.A. P s y c h o l o g i c a l and p h y s i o l o g i c a l mechanisms of p a i n . A n n u a l Review of P s y c h o l o g y , 1977, 28, 41-60. L u s t e d , L.B. S i g n a l d e t e c t a b i l i t y and m e d i c a l d e c i s i o n - m a k i n g . S c i e n c e , 1971, 171, 1217-1219. L u s t e d , L.B. R e c e i v e r o p e r a t i n g c h a r a c t e r i s t i c a n a l y s i s and i t s s i g n i f i c a n c e i n i n t e r p r e t a t i o n o f r a d i o l o g i c images. In E . J . Potchen ( E d . ) , C u r r e n t c o n c e p t s i n r a d i o l o g y . ( V o l . 2.) S t . L o u i s , Mo: Mosby, 1975. Mehrabian, A. N o n v e r b a l communication. C h i c a g o : A l d i n e - A t h e r t o n , 1972. Mehrabian, A., & E p s t e i n , N. A measure -of e m o t i o n a l empathy. J o u r n a l of P e r s o n a l i t y , 1972, 4_, 525-543. Mehrabian, A., & Weiner, M. Decoding o f i n c o n s i s t e n t communications. 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 P s y c h o l o g y , 1967, _6, 109-114. 55 Metz, C , S t a r r , S., & L u s t e d , L.B. Q u a n t i t a t i v e e v a l u a t i o n of s i g n a l d e t e c t -i o n performance i n m e d i c i n e . ROC a n a l y s i s and d e t e r m i n a t i o n of d i a g n o s t i c b e n e f i t . I n G.A. Hay (Ed.) M e d i c a l images: F o r m a t i o n , p e r c e p t i o n and measurement. London: W i l e y , 1977. N e u f e l d , R.W.J., & Davidson, P.O. The e f f e c t s o f v i c a r i o u s and c o g n i t i v e r e h e a r s a l on p a i n t o l e r a n c e . J o u r n a l of Ps y c h o s o m a t i c R e s e a r c h, 1971, 15, 329-335. P a s t o r e , R.E., & S c h e i r e r , C.J. S i g n a l d e t e c t i o n t h e o r y : C o n s i d e r a t i o n s f o r g e n e r a l a p p l i c a 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 , 1974, 81, 945-958. P r k a c h i n , K.M. I n t e r p e r s o n a l i n f l u e n c e s on p a i n e x p r e s s i o n s . U n p u b l i s h e d d o c t o r a l d i s s e r t a t i o n . U n i v e r s i t y o f B r i t i s h Columbia, Vancouver, B r i t i s h Columbia, Canada, 1978. P r k a c h i n , K.M., C r a i g , K.D., P a p a g e o r g i s , D., & R e i t h , G. N o n v e r b a l communi-c a t i o n d e f i c i t s and re s p o n s e t o performance feedback i n d e p r e s s i o n . J o u r n a l of Abnormal P s y c h o l o g y , 1977, 86, 224-234. Rogers, C.R. The n e c e s s a r y and s u f f i c i e n t c o n d i t i o n s of t h e r a p e u t i c p e r s o n -a l i t y change. J o u r n a l of C o n s u l t i n g P s y c h o l o g y , 1957,. 2JL, 95-103. Rollman, G.B. S i g n a l d e t e c t i o n t h e o r y measurement o f p a i n : A r e v i e w and c r i t i q u e . P a i n , 1977, _3> 187-211. S t a r r , S., Metz, C , L u s t e d , L. , & Goodenough, D. V i s u a l d e t e c t i o n and l o c a l i z a t i o n o f r a d i o g r a p h i c images. R a d i o l o g y , 1975, 116, 533-538. Stenson, H., Kl e i n m u n t z , B., & S c o t t , B. P e r s o n a l i t y assessment as a s i g n a l d e t e c t i o n t a s k . J o u r n a l of C o n s u l t i n g and C l i n i c a l P s y c h o l o g y , 1975, 43, 794-799. Stevens, S.S. P s y c h o p h y s i c s . New York: W i l e y , 1975. 56 Swets, J.A. S i g n a l d e t e c t i o n i n m e d i c a l d i a g n o s i s . I n J.A. Jacquez ( E d . ) , Computer d i a g n o s i s and d i a g n o s t i c methods. S p r i n g f i e l d , 111.: C h a r l e s C. Thomas, 1972. Thompson, S.C. D e t e c t i o n o f s o c i a l cues: A s i g n a l d e t e c t i o n t h e o r y a n a l y s i s . P e r s o n a l i t y and S o c i a l P s y c h o l o g y , 1978, _ , 452-455. T u r s k y , B. P h y s i c a l , p h y s i o l o g i c a l , and p s y c h o l o g i c a l f a c t o r s t h a t a f f e c t p a i n r e a c t i o n t o e l e c t r i c shock. P s y c h o p h y s i o l o g y , 1974, 11, 95-112. Tu r s k y , B., & S t e r n b a c h , R.A. F u r t h e r p h y s i o l o g i c a l c o r r e l a t e s of e t h n i c d i f -f e r e n c e s i n r e s p o n s e s t o shock. P s y c h o p h y s i o l o g y , 1967, 4_, 67-74. Waxer, P.H. N o n v e r b a l cues f o r a n x i e t y : An e x a m i n a t i o n o f e m o t i o n a l l e a k a g e . J o u r n a l of Abnormal Psychology-, 1977, 86, 306-314. Weisenberg, M. P a i n and p a i n c o n t r o l . P s y c h o l o g i c a l B u l l e t i n , 1977, 84, 1008-1044. Weisenberg, M., K r e i n d l e r , M.L., Schachat, R., & Werboff, J . P a i n : A n x i e t y and a t t i t u d e s i n b l a c k , w h i t e and P u e r t o R i c a n p a t i e n t s . Psychosoma- t i c M e d i c i n e , 1975, 3]_, 123-135. Woodrow, K.M., Friedman, C D . , S i e g e l a u b , A.B., & C o l l e n , M.F. P a i n d i f f e r -ences a c c o r d i n g t o age, sex, and r a c e . P s y c h o s o m a t i c Medicine,. 1972, 34, 548-556. 57 APPENDIX A CONSENT FORM NAME I hereby consent t o p a r t i c i p a t e i n a r e s e a r c h p r o j e c t t h a t i n v o l v e s t h a t I : 1) f i l l out a 33-item p e r s o n a l i t y q u e s t i o n n a i r e AND 2) view a number of v i d e o t a p e s taken of 30 p e o p l e who p a r t i c i p a t e d i n another experiment where they were s u b j e c t e d t o e l e c t r i c shocks o f d i f f e r i n g i n t e n s i t i e s , and r a t e the d i s c o m f o r t of each p e r s o n i n the v i d e o t a p e . A l l of t h i s w i l l t ake a p p r o x i m a t e l y one hour, t h i r t y m i n u t e s . At no time d u r i n g t h i s experiment w i l l I r e c e i v e any shocks m y s e l f . I may withdraw from t h i s experiment a t any time. I u n d e r s t a n d t h a t t h e r i s k s a r e m i n i m a l . The p e r s o n a l i t y q u e s t i o n n a i r e d a t a and r a t i n g s w i l l o n l y be a v a i l a b l e t o the p e r s o n n e l i n v o l v e d i n t h i s r e s e a r c h p r o j e c t . S i g n a t u r e Date 58 APPENDIX B POST-SESSION QUESTIONNAIRE 1. Do you t h i n k the treatment made a d i f f e r e n c e t o t h e p a i n o f the perso n s r e c e i v i n g the shocks? 1 2 3 4 5 v e r y much not a t so a l l Why o r why not? 2. D i d you f e e l c o n f i d e n t about your r a t i n g s of the p a i n of each p e r s o n i n the f i l m ? 1 2 3 4 5 v e r y n o t a t a l l c o n f i d e n t c o n f i d e n t Comment: 3. What do you f e e l was;the purpose of t h i s experiment? 4. D i d a n y t h i n g seem odd or s u s p i c i o u s throughout? 5. Rank each of t h e s e time p e r i o d s from 1 s t most i m p o r t a n t t o 4 t h most i m p o r t a n t i n making your r a t i n g s . 1) b e f o r e the l i g h t came on. 2) when the l i g h t came on u n t i l 2 seconds l a t e r . 3) more than 2 seconds a f t e r t h e l i g h t came on u n t i l i t went o f f . 4) a f t e r t h e l i g h t went o f f . 6. Do you f e e l t h a t your knowledge of t h e treatment a f f e c t e d your r a t i n g s of each s u b j e c t ' s d i s c o m f o r t ? I f so, how? 7. Rank the f o l l o w i n g i n terms of how your judgments. Use 1 f o r the most f o r e h e a d eyebrows e y e l i d s eyes mouth important they were i n d e t e r m i n i n g ; i m p o r t a n t , 2 f o r the n e x t , e t c . an g l e o f head s h o u l d e r "posture arm p o s i t i o n t o r s o p o s i t i o n hands THANK YOU FOR PARTICIPATING. 

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