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The effects of massed and distributed practice upon motor performance and learning in groups of different… Pouliot, Jacques 1971

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THE EFFECTS OF MASSED AND DISTRIBUTED PRACTICE UPON MOTOR PERFORMANCE AND LEARNING . IN GROUPS OF DIFFERENT INITIAL ABILITY By Jacques P o u l i o t B.P.E., Lav a l U n i v e r s i t y , Quebec, 1968 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF PHYSICAL EDUCATION i n the School of P h y s i c a l Education and Recreation We accept t h i s t h e s i s as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA June, 1971 In p r e s e n t i n g t h i s t h e s i s in p a r t i a l f u l f i l m e n t o f the r e q u i r e m e n t s f o r an advanced degree at 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 , I a g ree tha t the 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 and s t u d y . I f u r t h e r ag ree 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 pu rpo se s may be g r a n t e d by the Head o f my Department o r by h i s r e p r e s e n t a t i v e s . It 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 not 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 . J a c q u e s P o u l i o t Department o f P h y s i c a l EriimaHnn and Kprrp.aMnn The U n i v e r s i t y o f B r i t i s h Co lumbia Vancouver 8, Canada Date June 1971 ABSTRACT An investigation was conducted to determine i f the performance and learning of a pursuit rotor s k i l l was a function of practice sched-ule and i n i t i a l a b i l i t y level. Two groups of 30 subjects each were g i -ven two consecutive days of practice, with 22 and 20 t r i a l s respectively, on the pursuit rotor under different schedules of practice. The perfor-mance score of the massed practice group (30 sees, work, 5 sees, rest) was found to be significantly lower than that of the distributed practi-ce group (30 sees, work, 30 sees, rest) on the f i r s t day of practice. However, after 24 hours of interpolated rest, both groups were s t a t i s t i -cally equal in terms of the amount learned. A further analysis of the f i r s t day's performance scores of the 10 high i n i t i a l a b i l i t y and the 10 low i n i t i a l a b i l i t y subjects from each of the two main groups found no diff e r e n t i a l effect of practice schedule attributable to i n i t i a l a b i l i t y level. Further, there was no significant a b i l i t y levels by practice sched-ules interaction for learning. However, reminiscence was found to be re-lated to a b i l i t y level as low ab i l i t y subjects reminisced significantly more than high a b i l i t y subjects. TABLE OF CONTENTS CHAPTER PAGE I. STATEMENT OF THE PROBLEM 1 Introduction 1 The Problem 4 T h e o r e t i c a l Expectations . 4 D e f i n i t i o n s of Terms . . 6 Limitations of the Study 8 Delimitations of the Study 9 I I . REVIEW OF THE LITERATURE 1 0 Performance versus Learning 10 Theories concerned with the d i s t i n c t i o n between performance and learning ^ Experimental Studies Concerned With Massed versus D i s t r i b u t e d P r a c t i c e . . . . . ^3 Temporal Organization and H i e r a r c h i c a l Control i n S k i l l e d Performance . . . . . ^ A b i l i t y Level and Performance 2 2 I I I . METHODS AND PROCEDURES 2 8 Subjects . 2 8 O Q P r a c t i c e Schedules ° 2 R Experimental Design A b i l i t y Grouping J U Apparatus . ^ 32 Procedures 33 S t a t i s t i c a l Analysis CHAPTER IV. RESULTS AND DISCUSSION Results Discussion V. SUMMARY AND CONCLUSIONS Recommendations BIBLIOGRAPHY APPENDIX A Instructions APPENDIX B Raw Data LIST OF TABLES TABLE PAGE I. Summary of the t h e o r e t i c a l expectations f o r performance scores , 5 II . Summary of the t h e o r e t i c a l expectations f o r learning scores 6 I I I . Summary of the Experimental Design 29 IV. Means and Standard Deviations i n Seconds of the Two Main Groups f o r the Various Conditions 37 V. Analysis of Variance f o r the I n i t i a l Score . . . . . . . 37 VI. Analysis of Variance f o r the Performance Score . . . . . 38 VII. Analysis of Variance, f o r F i n a l Score One 39 VIII. Analysis of Variance f o r F i n a l Score Two 39 IX. Means and Standard Deviations i n Seconds of Each Subgroup f o r the Various Conditions 40 X. Analysis of Variance f o r the I n i t i a l Scores of the Four Subgroups 42 XI. Analysis of Variance f o r the Performance Scores of the Four Subgroups ^3 XII. Analysis of Variance f o r F i n a l Score One of the Four Subgroups ^ XIII. Analysis of Variance f o r F i n a l Score Two of the Four Subgroups ^ XIV. Analysis of Variance for Reminiscence Scores of the Four Subgroups ^ LIST OF FIGURES FIGURE PAGE 1. The Apparatus 31 2. Performance Curves of the Massed Practice and Distributed Practice Groups on the Pursuit Rotor for the Practice Sessions on Day One and Day Two 36 3. Day One and Day Two Performance Curves for the Four Subgroups as a Function of Their I n i t i a l Ability Level on the Pursuit Rotor 41 ACKNOWLEDGMENT I would l i k e to express my deepest appreciation to my advisor, Dr. R. Marteniuk, for h i s guidance and encouragement which began i n my i n i t i a l days as a graduate student at the University of B r i t i s h Columbia campus and culminated i n t h i s t h e s i s . I also wish to s i n c e r e l y thank a l l the members of my thesis com-mittee: Professor A. Bakogeorge, Professor N. Korchinsky and Dr. S.S. Lee f o r t h e i r h e l p f u l suggestions. I would l i k e to acknowledge f i n a n c i a l assistance from Le Ministere de 1'Education, Province de Quebec and the Fitness and Amateur Sport D i -rectorate. This aid made i t possible f o r me to continue my education at the graduate l e v e l . F i n a l l y , I cannot forget the contributions of my dear wife Colette to whom I owe a great deal. My degree and t h i s work equally r e f l e c t her s a c r i f i c e s and mine. CHAPTER I STATEMENT OF THE PROBLEM Introduction In a great deal of the experimental l i t e r a t u r e concerned with variables such as motivation, fatigue and d i s t r i b u t i o n of p r a c t i c e and th e i r influences upon motor performance and learning, there has been a gross neglect of a possible i n t e r a c t i o n occuring between i n d i v i d u a l d i f -ferences and experimental variables of i n t e r e s t . The fac t that l i t t l e a t t ention has been paid to i n d i v i d u a l differences as a quasi-independent v a r i a b l e i n learning studies i s probably a t t r i b u t a b l e to the fac t that workers i n the f i e l d of learning have usually been interested i n formula-t i n g general laws for behavior, with the i m p l i c i t assumption being that these laws w i l l hold throughout the range of learning a b i l i t y . There i s , however, l i t t l e experimental basis f o r t h i s assumption. In f a c t , i t has been shown by Pew (57, 58) that t h i s assumption does not hold f o r the temporal organization of the components of a continuous motor s k i l l . He found that when subjects (Ss) had to control the p o s i t i o n of a target dot on an o s c i l l o s c o p e by a l t e r n a t e l y switching between two keys, better con-t r o l over higher l e v e l s of response organization were acquired e a r l i e r i n t r a i n i n g by Ss with an i n i t i a l l y high a b i l i t y l e v e l as compared with Ss of i n i t i a l l y low a b i l i t y . As a r e s u l t of the high a b i l i t y Ss' superior temporal organization of the reponse patterns (open-loop behavior) , i t appeared that, l a t e i n p r a c t i c e , these Ss were able to perform the c r i t e -2 r i o n task almost automatically. However, the strategy used by low a b i -l i t y Ss (closed-loop behavior) required much more concentration and thus they were unable to a t t a i n the responding rate of the superior Ss. The differences between these two groups resulted i n quantitative and q u a l i -t a t i v e differences i n performing the motor s k i l l . I f i n d i v i d u a l differences i n a b i l i t y l i k e those described by Pew e x i s t i n other s k i l l s of a continuous nature, the question might be asked as to what e f f e c t d i f f e r e n t p r a c t i c e schedules would have on d i f f e r e n t i a l a b i l i t y groupings i n r e l a t i o n to performance and learning. Past i n v e s t i -gations (13, 24, 31, 69) i n t o the e f f e c t s that massed p r a c t i c e (MP) and d i s t r i b u t e d p r a c t i c e (DP) schedules have on motor performance and l e a r -ning have shown that MP, while considerably i n h i b i t i n g performance had l i t t l e or no influence on learning. These studies showed that when a r e s t i n t e r v a l was introduced, to allow f o r d i s s i p a t i o n of fatigue that resulted from MP, post-rest performance of the groups previously p r a c t i -cing under massed conditions was nearly equal to groups that had pre-v i o u s l y p r a c t i c e d under d i s t r i b u t e d conditions. This occurred despite the f a c t that the pre-rest performance of the MP groups was s i g n i f i c a n t -l y lower than the DP groups. However, a recent study by Marteniuk and Carron (52) has found r e s u l t s contrary to these findings. While a MP group performed j u s t as w e l l as a DP group on the f i r s t day of p r a c t i c e , a f t e r 24 hours of interpolated r e s t , the MP Ss demonstrated s i g n i f i c a n t -l y greater amounts of learning. An important consideration i n the Marteniuk and Carron study was the f a c t that they used a work-rest r a t i o f or MP that was d i f f e r e n t from 3 t h e c l a s s i c a l d e s i g n used i n d i s t r i b u t i o n o f p r a c t i c e s t u d i e s . P a s t i n v e s t i g a t i o n s (3, 13, 20, 24, 50, 66, 69) have u t i l i z e d c o n s t a n t work i n t e r v a l s f o r MP and DP w h i l e d i f f e r e n t i a t i n g between t h e s e groups i n terms o f t h e r e s t i n t e r v a l s . However, M a r t e n i u k and C a r r o n used c o n s -t a n t r e s t i n t e r v a l s w h i l e t h e work i n t e r v a l s were v a r i e d . Thus, t h e r e -s u l t s o b t a i n e d by M a r t e n i u k and C a r r o n s u g g e s t t h a t t h e i s s u e i n t h e s t u -dy of t h e most e f f i c i e n t s c h e d u l e o f p r a c t i c e l i e s i n t h e p r a c t i c e l e n g t h r a t h e r t h a n t h e l e n g t h o f the r e s t i n t e r v a l s , p r o v i d i n g t h a t t h e r e s t i n -t e r v a l s a l l o w f o r p e r i o d i c d i s s i p a t i o n o f any i n h i b i t o r y e f f e c t s f r o m p r e v i o u s p r a c t i c e . (52: 147) Combining t h e f a c t t h a t l o w - a b i l i t y Ss a r e more l i k e l y t o o p e r a t e on a c l o s e d - l o o p b a s i s w i t h t h e f a c t t h a t MP i n h i b i t s p e r f o r m a n c e , M a r t e n i u k and C a r r o n (52) have s u g g e s t e d t h a t , f a t i g u e , e s p e c i a l l y a c e n -t r a l - t y p e o f f a t i g u e r e s u l t i n g f r o m MP on the P u r s u i t R o t o r , may i n t e r f e r e w i t h the c o n t i n u o u s m o n i t o r i n g b e h a v i o r of the l o w - a b i l i t y Ss t o a g r e a -t e r e x t e n t t h a n w i t h t h e more automated b e h a v i o r of h i g h - a b i l i t y Ss. F u r -t h e r , i t was s u g g e s t e d t h a t t h i s c e n t r a l t y p e of f a t i g u e m ight i n f l u e n c e t h e l o w - a b i l i t y Ss' p o t e n t i a l t o l e a r n a motor t a s k i n t h a t i t might i n -h i b i t t h e development o f h i e r a r c h i c a l p r o c e s s e s . However, M a r t e n i u k and C a r r o n ' s r e s u l t s were c o n t r a r y t o t h e i r h y p o t h e s i s i n t h a t t h e l o w - a b i l i -t y MP group l e a r n e d c o n s i d e r a b l y more th a n t h e l o w - a b i l i t y DP group; To f o l l o w up t h e above h y p o t h e s i s , the p r e s e n t i n v e s t i g a t i o n has been c a r r i e d out t o see i f t h e c l a s s i c a l use o f w o r k - r e s t r a t i o s m i ght p r o d u c e the e f f e c t s t h a t were h y p o t h e s i z e d by M a r t e n i u k and C a r r o n (52). 4 The Problem The purpose of the present study was to inv e s t i g a t e the e f f e c t s that MP and DP schedules have on the performance and learning a b i l i t i e s of Ss d i f f e r i n g i n t h e i r i n i t i a l a b i l i t i e s on the Pursuit Rotor task. T h e o r e t i c a l Expectations On the basis of the t h e o r e t i c a l formulations elaborated previous-l y , two s p e c i f i c hypotheses w i l l be investigated. 1. Concerning performance, the working hypotheses w i l l be the following. a) Performance scores (PSs) for l o w - a b i l i t y Ss under MP w i l l be lower than the PSs for l o w - a b i l i t y Ss under DP; the PSs for h i g h - a b i l i t y Ss under the MP schedule w i l l be lower than the PSs f o r h i g h - a b i l i t y Ss under the DP schedule. b) Further, i t i s expected that the PSs f o r l o w - a b i l i t y Ss under DP w i l l be lower than PSs f o r h i g h - a b i l i t y Ss under MP. Also i t i s expec-ted that t o t a l PSs (MP + DP) for low a b i l i t y Ss w i l l be lower than the to-t a l PSs (MP + DP) f o r high a b i l i t y Ss. Table 1 schematically summarizes these working hypotheses for the PSs by ranking the scores (1 i s best) and comparing them on a r e l a -t i v e b a s i s . 5 TABLE I SUMMARY OF THE THEORETICAL EXPECTATIONS FOR PERFORMANCE SCORES Group Massed P r a c t i c e D i s t r i b u t e d P r a c t i c e High 2 < 1 A b i l i t y w Low A b i l i t y 4 < 3 I t i s expected that fatigue b u i l d up during MP w i l l depress per-formance when compared to performance under DP. The DP schedule i s such that fatigue d i s s i p a t e s during the frequent rest periods and thus never reaches a l e v e l that a f f e c t s performance. 2. Concerning learning the working hypotheses w i l l be the f o l -lowing: a) The learning scores (LSs) for l o w - a b i l i t y Ss w i l l be lower under MP than under DP. There w i l l be no differ e n c e i n the LSs of high-a b i l i t y Ss for both the MP and DP schedules. b) Further, i t i s expected that the LS for l o w - a b i l i t y Ss under DP w i l l be lower than the LS for h i g h - a b i l i t y Ss under MP. Table II schematically i l l u s t r a t e s the working hypothesis f o r the LSs i n a manner s i m i l a r to that followed for PSs. 6 TABLE II SUMMARY OF THE THEORETICAL EXPECTATIONS FOR LEARNING SCORES Group Massed Practice Distributed Practice High 1 = i Ability Low Ability 3 < 2 Since closed-loop behavior, which especially characterizes low-ab i l i t y Ss early in practice, i s a conscious phenomenon probably requi-ring considerable concentration, learning should be adversely affected by the fatigue built up under MP as compared with DP. However, high-a b i l i t y Ss working on open-loop behavior, which requires relatively l i t -tle concentration when compared to Ss working on a closed-loop basis, should not be affected by MP and thus i t is expected that no difference w i l l occur between high-ability Ss working under MP or DP schedules. Definitions of Terms Massed practice. This i s a practice schedule where the work periods on the criterion task are greater than the rest intervals. Since the rest interval i s rather short, fatigue tends to accumulate and as a 7 r e s u l t performance deteriorates. D i s t r i b u t e d p r a c t i c e . This i s a p r a c t i c e schedule where the work periods on the c r i t e r i o n task are equal to or shorter than the rest i n t e r v a l s . Performance i s at a maximum l e v e l at a l l times becau-se i t i s assumed that no fatigue accumulates. Performance. "This i s the score received on a s i n g l e d i s c r e t e t r i a l , or the average of a s p e c i f i c number of such t r i a l s during the t e s t i n g or measuring period." (23:27) Performance refe r s to a momenta-ry a b i l i t y l e v e l . t h a t could not only r e f l e c t learning but also the tem-porary e f f e c t s of fatigue, boredom or motivation. Thus when learning i s i n f e r r e d from performance a l l other variables that could i n h i b i t or f a c i l i t a t e performance must be c o n t r o l l e d . Learning. "This i s operationally defined as improvement i n per-formance consequent upon p r a c t i c e . " (23:27) In terms of the present stu-dy, learning i s the a c q u i s i t i o n of a h i e r a r c h i c a l process i n the organi-zation of response patterns through p r a c t i c e . This implies that early i n p r a c t i c e the learner executes each response as a separate u n i t , or on a closed-loop b a s i s , waiting for the feedback (F) from a response (R) and then i n i t i a t i n g a new response. ( i . e . R—-KF—*R—*F—*etc.) Later i n p r a c t i c e the learner programs several responses together before using error feedback, thus working on an open-loop basis, ( i . e . ^ " ^ ^ ^ ^ ^ ^ ^ R 2 ^ R n 2 - * F 2 - > e t c - ) Learning, as t r a d i t i o n a l l y defined, i s a r e l a t i v e l y permanent change i n behavior r e s u l t i n g from p r a c t i c e . (67:3) 8 Reminiscence. This i s operationally defined as an improvement in performance over rest without overt practice. It i s presumably due to the dissipation of reactive inhibition and/or fatigue which have ac-cumulated during the practice session. (67) Fatigue. In the present study, fatigue, reactive inhibition and performance decrement are used interchangeably. Practice under massed conditions results in poorer performance than practice under distributed conditions. There i s some controversy as to whether performance decre-ment i s actually due to a peripheral mechanism or to the inhibition of a central nervous mechanism. This issue, however, cannot be resolved in the present study. Warm-up decrement. "... is defined as a sudden i n i t i a l rise in performance after a rest." (35:350) The concept of warm-up implies that had the subject not lost his "set" during the rest (i.e. attitude toward the task or the posture adopted), his performance on the i n i t i a l postrest t r i a l or t r i a l s would have been better. Ability level. " A b i l i t i e s are variables postulated to account for individual differences in scores when experimental conditions are held constant." (49:536) ,In the present study, relative a b i l i t y level was determined by ranking individuals in terms of performance scores derived under con-trolled conditions. Limitations of the Study 1. Sixty volunteer undergraduate physical education students 9 were used as subjects. 2. Only right-handed, naive subjects were used. 3. Each subject was tested on two consecutive days but no at-tempt was made to control the subjects' activities during the interpola-ted rest. 4. The effects of changing the Day 1 MP schedule group to a DP schedule for Day 2 cannot be ascertained. Delimitations of the Study 1. The only motor s k i l l used was the pursuit rotor tracking s k i l l at a speed of 60 rpm. CHAPTER II REVIEW OF THE LITERATURE The f i r s t section of the following review of literature, descri-bes prior research in motor learning related to practice schedule and i t s effects upon motor performance and learning. This review i s mainly limited to those studies published since the major work of Ammons (6) in 1947. The second section of the review covers temporal organization in skilled performance and a b i l i t y level. Performance versus Learning Theories concerned with the distinction between performance and  learning. Current theoretical approaches to motor learning (6, 37, 50) based mainly on Hull's (29) work have distinguished between performance and learning. It has been demonstrated repeatedly with various verbal and motor tasks (13, 31, 59, 66, 69) that the performance curve, for MP Ss i s depressed relative to the performance curve for Ss practicing under a DP schedule. However, these studies also have shown that i f a long enough rest period i s introduced, the post-rest performance level for the MP group improves to a level approximating the performance level of the DP group. Such an improvement over rest without overt practice i s referred to as reminiscence. Thus whether performance represents amount learned depends upon the presence or absence of certain performance variables. In particular, these include reactive inhibition, conditioned inhibition, reminiscence and warm-up decrement. Kimble (50), extending upon the H u l l i a n concepts (29:122) of conditioning phenomena such as e x t i n c t i o n and spontaneous recovery, has attempted to elaborate a theory that would account f o r the phenomena oc-cu r r i n g under MP conditions. Kimble (50) stated that the consistent su-p e r i o r i t y of DP over MP during s k i l l a c q u i s i t i o n r e s u l t s from the MP producing a p e r i p h e r a l type of i n h i b i t i o n c a l l e d reactive i n h i b i t i o n (Ir) which has the e f f e c t of reducing the work output of the performer. As a r e s u l t of I r buildup, a second decremental process i d e n t i f i e d as con-ditioned i n h i b i t i o n ( s i r ) i s produced. According to Kimble, I r i s e s s e n t i a l l y a negative drive which resembles f a t i g u e . I t i s temporary i n nature and d i s s i p a t e s with r e s t . However, i f the voluntary rest i n t e r v a l s imposed by the experimenter du-r i n g the p r a c t i c e schedule are too short to allow f o r the d i s s i p a t i o n of the majority of the accumulated I r (as i n the case of MP), then I r c o n t i -nues to accumulate and greater need to r e s t develops. At t h i s point an involuntary r e s t pause occurs, performance decreases, and part of the Ir d i s s i p a t e s , causing a need, reward, or reinforcement. This r e i n f o r c e -ment produces a habit of not responding c a l l e d s i r . Since s i r i s a habit, and thus permanent, i t i s unaffected by the r e s t periods introduced i n the p r a c t i c e schedule and s t i l l operates to depress performance when l e a r -ning i s resumed following an interpolated rest period. This two-factor theory ( i . e . I r and s i r ) of i n h i b i t i o n elaborated by Kimble has been extensively used i n the l i t e r a t u r e to explain tempora-ry and permanent decrement i n studies dealing with the r e l a t i v e e f f i c i e n c y of MP and DP upon motor performance and learning. However, t h i s theory has been subject to c r i t i c i s m f o r i t s f a i l u r e to account for the s p e c i f i c post-rest phenomena which characterized the post-rest performance curve fo r the MP group. These post-rest phenomena i d e n t i f i e d by Ammons (6) include: (1) a sharp i n i t i a l r i s e (warm-up) i n the performance curve, which i s followed (2) by a r e l a t i v e decrement, and then (3) a resumption of the i n i t i a l r i s e . Further, i t has been shown by Adams and Reynolds (3) that permanent work decrement ( s i r ) i s not r e a l l y permanent. S h i f t s from massed to d i s t r i b u t e d p r a c t i c e leads to s h i f t i n performance such as to make the performance of the s h i f t e d group resemble the performance of the other group u n t i l there i s a c t u a l l y no defference between the two groups. Similar findings have been reported by Archer and W i l l i g (14), Denny, Frisbey and Weaver (30) and Reynolds and Adams (62) Eysenck (37), i n a thorough review of the l i t e r a t u r e dealing with t h i s two-factor 'theory of i n h i b i t i o n presents some evidence that argues against the i n h i b i t i o n theory postulated by Kimble (50). Using Kimble's formulation, Eysenck (37) prefers to explain I r as the r e s u l t of a cen-t r a l type of fatigue rather than the p e r i p h e r a l type that Kimble has pos-tulated. Thus Eysenck rel a t e d the amount of i n h i b i t i o n to the duration of continued attention required by the task ( i . e . a "mental work" hy-pothesis rather than a " p h y s i c a l " one). Evidence f o r the existence of reminiscence e f f e c t s i n almost purely perceptual task (11) and studies of b i l a t e r a l t r a n s f e r e f f e c t s (10, 42), further serve to d i s c r e d i t the p e r i p h e r a l hypothesis. To explain the "mental work" hypothesis, Welford (72:260-262) states that the presence of fatigue or I r would imply some temporary c e n t r a l impairment e i t h e r caused by l o c a l neural impairment 13 where groups of nerve cells concerned with performance become insensiti-ve or by an increase of "neural noise" where fatigue resulting from the accumulated after-effects of stresses and annoyances would cause over-activity i n the brain or parts of i t . To close the discussion on the nature of Ir, Ammons and Ammons (12) after twenty years of research dealing with the problem have con-cluded that temporary work decrement is partially central in nature and seems to affect skilled performance by causing a partial distortion or disintegration of habits through a kind of f i l t e r i n g process. Thus accor-ding to Ammons and Ammons, Ir would be more related to a perceptual pro-blem where the S perceives the wrong cues instead of the proper ones which are necessary to perform the task properly. Although the information presented here does not offer any f i n a l solution concerning the nature of temporary work decrement, i t does c l a -r i f y i n more precise terms, Kimble's two-factor theory of inhibition. Experimental studies concerned with massed vs. distributed prac- tice. Singer (66) investigated the effects of massed and distributed practice upon the performance and learning of a novel basketball s k i l l . The s k i l l involved bouncing a b a l l off the floor into a basket. One hundred and twenty male Ss were divided into 3 groups of 40 Ss each and each group was assigned to MP or DP conditions. One group continuously attempted 80 shots at the basket while a second group paused 5 min. after each 20 continuous attempts and a third group rested 24 hr. between each of the four sessions. An analysis of variance for performance scores upon completion of practice and for learning scores after a 24 hr. inter-polated rest period revealed that the most DP schedule (the 24 hr. rest group) performance was s t a t i s t i c a l l y superior. However i n terms of l e a r -ning no s i g n i f i c a n t differences between groups were found. The e f f i c i e n c y of two p r a c t i c e schedules on two large muscle mo-tor tasks (stabilometer and ladder climb) was examined by Stelmach (69). One hundred and s i x t y subjects divided i n t o four groups were assigned to one of the two motor-tasks under one of two p r a c t i c e schedules. D i s t r i -buted p r a c t i c e consisted of a work-rest r a t i o of 30 sec. work- 30 sec. r e s t ; MP was continuous f o r 8 minutes. Comparisons made during the l a s t minute of p r a c t i c e p r i o r to a major rest pause revealed that the MP group showed a s i g n i f i c a n t decrement i n performance l e v e l . In contrast, when pr a c t i c e was resumed under a DP schedule, following 4 min. of interpo-l a t e d r e s t , no d i f f e r e n c e was found i n the amount learned. The findings applied to both the stabilometer and the ladder climb. An unpublished study by P o u l i o t (59) found r e s u l t s s i m i l a r to those of Stelmach's. Fourteen male students were evenly divided i n t o MP and DP conditions for learning a pursuit rotor s k i l l . I t was found that the DP group (20 sec. work, 30 sees, rest) performed s i g n i f i c a n t l y better (p<05) than the MP group (20 sees, work, 0 sec. rest) p r i o r to a 10 min. rest period allowed at the end of session one. However, a f t e r the i n t e r p o l a t e d r e s t , no s t a t i s t i c a l difference was found between the performance scores of the two groups. Carron (23) using the peg turn apparatus, which i s a d i s c r e t e motor task, i n v o l v i n g a short l i n e a r movement, tested 300 male Ss under two d i f f e r e n t highly massed schedules and three d i f f e r e n t d i s t r i b u t e d schedules. The r e s u l t s support the hypothesis that while increasing the amount of massing does have a deleterious e f f e c t on performance, i t does not reduce the amount learned. On the other hand, a recent i n v e s t i g a t i o n by Marteniuk and Carron (52) has presented findings contradictory to the above fin d i n g s . One hundred volunteer u n i v e r s i t y females were assigned randomly to e i t h e r a MP or DP schedule. Both groups performed 15 t r i a l s on each of 2 succes-sive days (24 hr. r e s t was allowed between the two sessions) on the Pur-s u i t Rotor. Massed p r a c t i c e on the f i r s t day had a work-rest r a t i o of 40 sees, work, 20 sees. r e s t . On Day 2, the MP group p r a c t i c e d under the same work-rest r a t i o as the DP group (20 sees, work, 20 sees. r e s t ) . On Day 1, i t was found that the MP group performed j u s t as w e l l as the DP group with a s u b s t a n t i a l portion of the MP group's scores being supe-r i o r to those of the DP group. Following the 24 hr. interpolated r e s t , the MP Ss demonstrated s i g n i f i c a n t l y greater amounts of learning on Day 2. The r e s u l t s obtained here for performance scores and learning scores contradict past i n v e s t i g a t i o n s . I t would seem that the difference i n methods of d i s t r i b u t i n g p r a c t i c e may have been a contributing f a c t o r i n y i e l d i n g these r e s u l t s . In f a c t , the schedules used were d i f f e r e n t from the schedules used i n t r a d i t i o n a l methods of d i s t r i b u t i n g p r a c t i c e where the i n t e r t r i a l r e s t i s varied and the work i n t e r v a l i s kept constant. The authors concluded that "the relevant issue i n the study of the most e f f i c i e n t schedule of p r a c t i c e i s not whether of not fatigue i s present during performance but whether there e x i s t s some optimum p r a c t i c e length a f t e r which there occurs maximum benefits from an in t e r p o l a t e d r e s t " . (52:147) 16 Temporal Organization and H i e r a r c h i c a l Control i n S k i l l e d Performance. The following review of l i t e r a t u r e dealing with s k i l l e d perfor-mance and i t s temporal organization has the purpose of attempting to present a general view of the a c q u i s i t i o n of s k i l l e d performance. In so doing i t i s hoped that the reader w i l l better understand the problem and the t h e o r e t i c a l expectations of the present study as stated i n Chap-ter One. In.an attempt to understand s k i l l e d motor performance and l e a r -ning, several researchers (39, 40, 56) have formulated theories e x p l a i -ning the organization of the mechanisms responsible for the execution of s k i l l e d behavior. The e f f e c t o r system as seen by these models exe-cutes a sequence of commands issued by the c e n t r a l d e c i s i o n mechanisms. In essence they explained how the responses of an i n d i v i d u a l are p r e c i -sely matched to the task and to the dynamic properties of body and limbs. It i s assumed that a l l the information necessary to perform a motor task, having been acquired through p r a c t i c e and past experiences, are directed by e f f e c t o r programmes. Most of t h i s information according to Crossman (28:35), i s held i n a permanent store b u i l t up during the a c q u i s i t i o n of various s k i l l s . Further, i t would seem that h i s information which i s stored and responsible f o r t i h e control and coordination of muscular movement i s organized i n a h i e r a r c h i c a l manner as advanced by Lashley (51), M i l l e r , Galanter and Pribram (56), and Hearnshaw (43). To best describe how s k i l l e d performance i s organized i n man and by extension, how the e f f e c t o r mechanism operates, F i t t s (40, 41) has made an analogy to a computer. According to F i t t s , information necessary to perform a particular s k i l l is selected and governed by a program or sequence of instructions. These short, fixed sequences of instructions or operations are written as subroutines which may be called into play by an overall program which controls a particular mo-tor activity. These subroutines may be repeated over and over again u n t i l some predetermined point i s reached or un t i l i t i s interrupted by the overall program. The executive program provides the overall logical or decision framework that gives the system i t s flexible and adaptive characteristics. Learning, then, as seen by Fitts would involve a new integra-tion and ordering of these fixed subroutines, many of which may be transferred as a whole from other activities. (41:10-11) Crossman (28) has pointed out that the basic s k i l l s or subroutines are acquired pie-cemeal during the lengthy period of t r i a l and error behavior in child-hood. This account of s k i l l acquisition gives an overall view of the sequential and hierarchical organization of skilled performance. In essence the basic subroutines are at the lowest order of organization, while higher level programs or plans can modify the lower ones on the basis of accumulated information acquired from past experiences. Support for viewing behavior as involving temporal and hierar-chical organization has come from Woodworth (76) when he pointed out that behavioral activities are frequently organized i n two or more stage. In a well determined activity, like the golf swing for instance, each part, such as the grip, the stance, the backswing, etc., may be i d e n t i f i e d as a stage. These stages or subroutines represent a h i e r a r -chy of motor units oriented towards a s p e c i f i c goal. One of the f i r s t studies to investigate t h i s temporal organi-zation i n s k i l l e d learning was the c l a s s i c a l work of Bryan and Harter (21, 22). Their papers contained the f i r s t known records of learning i n sending and r e c e i v i n g Morse Code. The learning curves f o r r e c e i v i n g Morse Code showed that one acquires a hierarchy of habits. According to these r e s u l t s , Bryan and Harter (22:356) concluded: " . . . that the telegrapher must acquire besides l e t t e r , s y l l a b l e and word habits, an array of higher language habits, associated with the combination of words i n connected discourse. Mastery of the telegraphic language i n -volves mastery of the habits of a l l orders." This means that l e t t e r s must f i r s t be mastered, then s y l l a b l e s and words, and f i n a l l y , phrases and sentences. Further, i t appeared that mastery of the higher-order habits depended on the mastery of the lower-order ones. To receive sen-tences, that i s , one must f i r s t have acquired the component word-habits; to receive words, one must have acquired the l e t t e r - h a b i t s . Further evidence f o r the b u i l d i n g up of sequences of action into higher units of performance has also been provided i n an experiment by Book (19) concerned with learning to typewrite. The stages i n l e a r -ning to typewrite by the "touch method", with the keyboard concealed by a screen were as follows: E a r l y i n learning, the Ss acquired the l e t t e r -habits where one l e t t e r at a time was struck, and the response checked for i t s accuracy. Later on, the word-habits were acquired. Now that each letter and i t s place on the keyboard had been learned, the Ss were able to program and execute a series of letters together without inter-ruption. This enabled them to type a series of words at a faster rate. Finally, a continuous sequence of words or even a phrase was struck as an entity without interruption. In other words, as the typist became s k i l l f u l , she took words and phrases as a single complex response. (54:66-67) Control of details by broader aspects of performance was further illustrated in a series of experiments by Pew (57,58) whose Ss attempted to control position of a target dot on an oscilloscope by alternately switching between two keys. When the left-hand key was depressed, the target accelerated to the l e f t . When the right-hand key was pushed the target decelerated, reversed direction, and accelerated to the right. The S's task was to keep the target dot as near the centre to the screen as possible for the duration of each t r i a l . Accurate performance demanded a rapid alternation between the two keys. Pew noted that the strategies used in dealing with this task could be divided into three types. Early i n training, the simplest, but least effective,was to observe the effect of pressing each key before pressing the other; this resulted i n a series of large overshoots. Pew classified this particular strategy as a "closed loop" mode of operations in which the student responded, waited for feedback about the results of this response, and then initiated a new response the intent of which was to compensate for the inadequacies of the previous one. Pew (57,58) called this mode of responding "closed-loop" behavior. A second strategy, used late in practice, occured when the student ut i l i z e d error feed-back over a longer time span which Pew (57,58) called "open-loop" be-havior. The third strategy again involved pressing the keys alterna-tely in rapid succession but adjusting the intervals between each res-ponse so that the spot remained approximately at the centre of the tar-get. With this mode, identified as a modulation-mode, there were no pauses for corrections. It involved a continuous modulation of the inter-response time. Thus the S appeared, to observe and control not instantaneous target position, rate^ or acceleration, but the mean re-sult which was achieved by a sequence of responses. The Ss using this kind of responding-mode imposed a pattern of timing upon their perfor-mance which ordered the individual actions so as to maintain a uniform overall result.(57:53) This introduction of higher-order control meant that the S was able to organize a sequence of responses at a higher l e -vel, taking into account the effects of more than one response at one time.-Finally, Ammons (9) investigated the temporal patterning of the contacts or "hits" for the Pursuit.Rotor under different distributions of practice. According to the author, a simple time on target i s not sufficient to study the nature of the rotary pursuit response and i t s acquisition. The purpose of the study was to determine the effects of distribution of practice upon performance in rotary pursuit as measured by the number of hits, v a r i a b i l i t y i n number of hits, mean duration of hits, v a r i a b i l i t y in mean duration of hits, mean duration of misses, and v a r i a b i l i t y in mean duration of misses. Due to the fact that twelve to fifteen hours were required to read and evaluate each record, only 10 Ss per group were used. The massed group was given 36 t r i a l s of 22 sees, duration without a rest between t r i a l s while the distributed group rested 5 min. between each pair of 22 sec. t r i a l s . Results i n -dicated that the mean duration of hits showed a negatively accelerated increase during practice for both groups. The number of hits and mean duration of hits was greater for the DP group than for the MP group. Finally, mean duration of misses were less during DP, decreasing quick-ly to a stable minimum of about 4 sees.''" Ammons concluded that the hit indices permitted clear differentiation between performance under MP and DP schedules. In terms of temporal organization, this study showed that Ss learn to make longer and longer unbroken sweeps and to correct more quickly for deviations from these movements which would take him off the target. Thus, Ammons maintained that the Ss learned to make longer and longer sweeping type movements of both eyes and the tracking hand and that they also learned to correct "errors" in a shor-ter time, both because they were sensitive to more cues than i n i t i a l l y and because they had learned more efficient corrective movements. Im-provement took place because the Ss were able to make longer and longer movements without direct "voluntary" control. (9:21) (1) A miss roughly represents the duration of a combination visual and kinesthetic reaction time to the start of a movement of the stylus tip off the target plus the duration of the corrective movement. It appeared that this adjustment could not be made, on the average, in less than about .4 sec. It is interesting to note that Craik (25,26) and Vince (71) found that i t took from .4 to .5 sec. to make similar corrections during linear tracking. 22 In summary of this section i t can be stated that commands res-ponsible for the execution of movement are issued by the central mecha-nisms, and are directed by stored effector programmes. These commands comprising the effector programmes have been stored through learning and are organized in a hierarchical manner. The acquisition of higher response patterns, such as open-loop mode and modulation mode i s based on the fact that basic subroutines involved in movement are automati-cally executed. Further, Welford (71:194) points out that the level at which awareness is centered should rise as the operator becomes more expert and masters larger and larger units. Thus performance tends to become stereotyped in the course of practice, and the whole cycle can be run off very much as a chain response with each member acting as the cue for the one that follows. At this performance level, i t i s pos-sible ,to organize a sequence of action without immediate feedback so that performance is essentially anticipatory and b a l l i s t i c . This has been verified by Pew (57,58) when he found that Ss were able to free themselves from the need.of continuously monitoring the most elementary parts of their own performance and thus were able to exert control over larger sets of responses at the higher level of organization.(57:70) Ability Level and Performance When individual differences in the acquisition of a psychomotor response are studied, one question arises: What is the nature of the acquisition curves for Ss having different levels of i n i t i a l a b i l i t y in the task? This question bears on such problems as the interaction bet-ween ab i l i t y measures and learning variables, and what might be expected in the training of Ss differing i n i n i t i a l a b i l i t y in a task. In an extensive study, Reynolds and Adams (2, 63) investigated the i n t e r a c t i o n between i n d i v i d u a l differences and d i s t r i b u t i o n of prac t i c e on the Pursuit Rotor. Nine-hundred and s i x t y Ss were assigned i n equal numbers to eit h e r DP or MP schedules and were trained under these schedules throughout three or four sessions respectively, with each session consisting of twenty t r i a l s . The duration of each t r i a l was 20 sees, f o r both groups. The i n t e r t r i a l r e s t was 5 sees, f o r the mas-sed group and 60 sees, f o r the d i s t r i b u t e d group. There was a 30 min. rest between sessions. Upon completion of the study, Ss within each experimental group were s t r a t i f i e d into d e c i l e s on the basis of t h e i r cumulative scores f o r the f i r s t f i v e t r i a l s . Thus 10 subgroups were obtained f o r each p r a c t i c e schedule. T o t a l group comparisons showed that the curves obtained under the two conditions of p r a c t i c e d i s t r i b u t i o n were s i m i l a r to those usual l y observed with MP and DP on the rotary pursuit t e s t . Comparisons between performance curves were then done among sub groups f o r each p r a c t i c e condition. In other words, performance curves f o r low and high-deciles under MP. conditions were compared f o r d i f f e -rences i n t h e i r slopes throughout each session. The same was done f or low and high de c i l e s under DP conditions. Within each group, under both MP and DP, the i n i t i a l slope i n the f i r s t session appeared to be much steeper f or h i g h - a b i l i t y Ss than the l o w - a b i l i t y Ss. In other words, greater improvement took place during the early t r i a l s f o r Ss having i n i t i a l l y a h i g h - a b i l i t y l e v e l . Under MP, the curve f o r the lower d e c i l e tended to be l i n e a r i n form with a slow rate of r i s e throughout. The curve f o r the highest d e c i l e showed rapid increases i n i t i a l l y , and then e s s e n t i a l l y zero slope. Under DP, the curves d i f -f e r i n g i n slope-constants were e s s e n t i a l l y the same as i n the case of, MP. The combined curves f o r the two main groups were quite r e p r e s e n t a t i -ve of the curve f o r each of the d e c i l e s . F i n a l l y , the mean curves were e s s e n t i a l l y p a r a l l e l i n the f i n a l session, with l i t t l e tendency to con-verge. It-appeared that a l l Ss did not a t t a i n the task-assymptote but rather attained an assymptote commensurate with t h e i r own a b i l i t y . The r e s u l t s of t h i s study are - consistent with those of Farmer (38) who showed p a r a l l e l performance curves f o r groups of d i f f e r e n t i n i t i a l a b i l i t y and supports the assumption of H u l l (45) that i n d i v i -dual differences a f f e c t the constants of a behavioral equation but not the general mathematical form. The relationship, between c e r t a i n measures of a b i l i t y and the a c q u i s i t i o n of a four-unit d i s c r i m i n a t i o n reaction time test (where speed of an arm-hand response to a v i s u a l d i scrimination i s measured) has been investigated by Adams (5). Eight hundred and s i x t y Ss were tested and a l l Ss performed 160 t r i a l s continuously. The Ss were s t r a -t i f i e d i n t o . d e c i l e s on the basis of t h e i r score on t r i a l one. The per-formance curves indicated that generally the deci l e s maintained t h e i r i n i t i a l rank order throughout t r a i n i n g . The curve f o r the lowest d e c i -l e showed a great deal of improvement early i n t r a i n i n g . As the l e v e l of i n i t i a l a b i l i t y increased, the performance curves tended to be l i -near throughout p r a c t i c e . The 10 curves obtained were e s s e n t i a l l y pa-r a l l e l i n the f i n a l t r i a l s and there was l i t t l e i n d i c a t i o n that they were going to eventually converge to a common level since each group appeared to be approaching i t s own assymptote. A certain number of i n i t i a l l y poor Ss in decile one made a transition to the level of i n i -t i a l l y proficient Ss (decile 10) as training progressed. As a matter of fact, by t r i a l 16, a substantial number of decile one Ss were equal or superior to the performance of decile 10 Ss. The findings of this study are similar to those of Reynolds and.Adams (2, 63). However, i t is d i f f i c u l t to interpret these results in terms of performance and learning since practice was continuous and only included a single session. The results obtained by Reynolds and Adams (2, 63) and Farmer (38) are consistent with Hull's (45) postulate that a l l individuals be-have the same way, in a given condition, according to a set of esta-blished primary laws which are expressed under the form of an equation (that i s : E = H x D). Further, Hull postulated that Ss with innate s r s r r differences, mostly due to differences i n past experiences, w i l l behave according to the general laws established while only the constants of this general law w i l l be affected. A recent investigation by Marteniuk and Carron (52), which was discussed previously (p. 14) i n this chapter, looked at the effect of MP and DP upon pursuit rotor performance and learning i n groups of d i f -ferent i n i t i a l a b i l i t i e s and found results somewhat different to those discussed above. Marteniuk and Carron formulated the following hypo-thesis: If individual differences in abilit y , . . . exist in other s k i l l s of a continuous nature, then the question might be asked as to whether schedules of practice which di f f e r i n their work-rest ratio differentially affect low and high-ability Ss in relation to performance and learning. . . ., i f i t can be assumed that low-ability Ss are more likely to operate on a closed-loop basis early in practice, then fatigue, especially a central type of fatigue that results from MP on the pursuit rotor, could interfere with this continuous monitoring behaviour to a greater extent than with the more automated be-haviour of high-ability Ss. It might also be expec-ted that fatigue would influence the low-ability Ss' potential to learn a motor task in that the presence of fatigue would inhibit the development of hierar-chical processes. (52:141) To test this hypothesis, the mean of the f i r s t two t r i a l s perfor-med under a DP schedule was used to divide, within each group, the MP and DP groups into low and high-ability subgroups of 15 Ss each. Upon completion of the practice sessions, an analysis of variance revealed a significant a b i l i t y level by practice schedule interaction late in prac-tice. It appeared that the low-ability Ss under the MP schedule learned more than the high-ability Ss under MP when compared to the corresponding scores of the two DP groups. Of interest was the fact that late in lear-ning the performance curve for the low-ability MP subgroup was essential-ly equal to that of the high-ability DP group. The greater learning of the low-ability Ss under MP was not expected and could not be explained. However, these results are consistent with findings reported by Reynolds and Adams (63) and Adams (5) when they observed throughout their study that a substantial number of i n i t i a l l y low-ability Ss performed, late in practice, as well as high-ability Ss. Adams (5) has suggested that this transition may be caused by the fact that some Ss have low i n i t i a l status because of lack of prior experiences in one or more extra-experi-mental situations. When given the opportunity to practice, however, a number.of these i n i t i a l l y poor Ss achieve a performance level that i s equal to or superior to that of i n i t i a l l y proficient Ss because of rapid acquisition rates and/or because of possession of a high level of one or more factors necessary to perform the task. In summary, i t has been shown that differing results have been obtained when individual differences were employed as a quasi-indepen-dent variable in learning studies. Reynolds and Adams (63) have concluded that general laws of learning based on sample statistics hold throughout the range of learning a b i l i t y . Farmer (38) showed parallel performance curves for Ss differentiated on the basis of their i n i t i a l level of abi-l i t y . Pew (58) on the other hand had demonstrated a different temporal organization, developed through practice, for Ss with different i n i t i a l a b i l i t y levels. Several studies (5, 33, 73, 77) have shown a tendency for groups of different i n i t i a l a b i l i t i e s to become closer at the end of practice without converging. One exception to these findings was Marteniuk and Carron's (52) study where a low-ability MP group demonstra-ted learning that was superior to a high-ability group trained under DP. These results were obtained, however, by using a distribution of practice schedule different from conventional methods of distributing practice. In fact Marteniuk and Carron varied the work interval while keeping the rest interval constant when, conventionally, the work interval i s kept constant and the rest interval varies. From these findings, then, i t appears that further research dealing with individual differences and practice schedules is warranted. CHAPTER I I I METHODS AND PROCEDURES Subjects Sixty volunteer r i g h t handed male Ss with a mean age of 21.77 years (SD = _+ 2.88 yrs.) were used. The Ss were students e n r o l l e d i n p h y s i c a l education classes at the University of B r i t i s h Columbia and were nalfve to the Pursuit Rotor apparatus. They were randomly assigned to either a MP or a DP schedule with the r e s t r i c t i o n that equal numbers appear i n each group. P r a c t i c e Schedules D i s t r i b u t e d pract i c e . The DP schedule used was based on a work-rest r a t i o of 30 sec. work-30 sec. re s t . Massed p r a c t i c e . The MP schedule used was based on a work-rest r a t i o of 30 sec. work-5 sec. re s t . Experimental Design A summary of the experimental design i s presented i n Table I I I . Both the MP and DP group performed 22 t r i a l s on the Pursuit Rotor on Day 1 of the experiment. The f i r s t two t r i a l s were performed under the DP schedule f o r both MP and DP groups, i n order to have a supposedly true score of the Ss' i n i t i a l a b i l i t i e s . I t was assumed that t h i s score was free from any i n h i b i t o r y e f f e c t s such as fatigue or boredom. These two t r i a l s were followed by 30 sees. r e s t . The next 20 t r i a l s were perfor-med under the MP or the DP shedules depending on which experimental T-ABLE III SUMMARY OF THE EXPERIMENTAL DESIGN GROUPS INITIAL SCORES PERFORMANCE SCORES FINAL SCORES DP 'Two tr i a l s Twenty t r i a l s 4-1 Twenty t r i a l s 1. High Ability - 3 0 sees, work rest - 3 0 sees, work res - 3 0 sees, work 2. Low Ability - 3 0 sees, rest cu - 3 0 sees, rest olated - 3 0 sees, rest lat olated MP Two tr i a l s nterpo Twenty t r i a l s interp Twenty t r i a l s 1. High Ability - 3 0 sees, work •H CO - 3 0 sees, work urs - 3 0 sees, work 2. Low Ability - 3 0 sees, rest sec - 3 0 sees, rest 24 ho - 3 0 sees, rest o CO 24 ho 1. The i n i t i a l scores were the means of the f i r s t two t r i a l s on Day 1 2. Two f i n a l scores were computed: . - fin a l score 1 was the mean of the f i r s t two t r i a l s on Day 2, - f i n a l score 2 was the mean of the last two t r i a l s on Day 2. group the S was in. The performance scores (PSs) used for comparison purposes were the average of the last two t r i a l s on Day 1. On Day 2, following an interpolated rest of approximately 24 hrs. that permitted total dissipation of the "fatigue" accumulated during the previous day's practice, a l l Ss performed 20 t r i a l s under the DP schedule. Again i t was assumed that performance at this stage would represent "true" performance in that no inhibitory effects would be present. Two f i n a l scores for each group were calculated: One was the ave-rage of the f i r s t two t r i a l s on Day 2 (FS^), and the other was the ave-rage of the last two t r i a l s on Day 2 (FS£). The relative, amount of i n -hibition built up during Day 1 performance was determined by the reminis-cence score (RS) which was the difference between FS^ and PS. Ability Grouping Upon completion of the practice sessions, the mean of the f i r s t two t r i a l s on Day 1 was used to determine the i n i t i a l a b i l i t y (i.e. the i n i t i a l score -IS) of each S. The Ss from each group were them divided into two subgroups on the basis of their ISs. Those with the 10 lowest scores were assigned to the low a b i l i t y group and those with the 10 highest scores to the high a b i l i t y group. Thus there were four groups of 10 Ss each, a low and a high a b i l i t y group that practiced under MP conditions and two similar groups that practiced under DP conditions. Apparatus The pursuit rotor. The learning task was the Pursuit Rotor ( F i -gure 1) . This apparatus had been purchased from the Lafayette Instrument 0 0 9) Co. - model 2203 - and consisted of an el e c t r i c a l turntable mounted on a wooden frame. The turntable of the rotor, covered by black formica, had a 25.5 cm. diameter and contained, flush to the turntable, a metal target 1.9 cm. i n diameter and situated 8.3 cm. from the center of the turntable. The rotation of the turntable was set at 60 rpm. A spring loaded brass stylus was attached to a wooden handle and was connected to the rotor. When contact was made between the stylus and the metal disk, a circuit was closed and a timer activated. When the stylus was not i n contact with the disc, the timing circuit was open. The turnta-ble revolved in a clockwise direction and was situated 88 cm. from the floor. The timer. A Klockqunter - model 120A - made by Hunter Mfg. Co. was employed. It recorded'the time on target to 1/100 of a second. Procedures The instructions for performing the Pursuit Rotor (see Appendix A) were read by each S before performing the task. The S was then asked to verbally explain the procedures to the experimenter (E) and to feel free to ask questions. However, only questions dealing specifically with the task were answered. Questions dealing with the purpose of the task or length of the t r i a l s or rest periods were not answered. On the second day of testing, the E brie f l y reviewed the instructions with each S. On the f i r s t day of testing the Ss, standing in front of the appa-ratus, were told to hold the stylus handle lightly in the right hand with a tennis-type grip which was then demonstrated. They were then told that the object of the task was to track the metal disk by keeping the metal stylus in contact with i t for as long as possible during each t r i a l and that the timer would record the amount of time spent on the target. They were warned that the tracking movement should be done with an easy, re-laxed swinging movement of the arm and that no extra pressure should be put on the stylus tip in any way. Performance deviating from these inr: structions during the experiment was corrected verbally. For the start of each t r i a l , the Ss held the stylus tip on the right side of the turn-table at an angle of 180° from the target. When the turntable was start-ed by E, the Ss were instructed to hold the stylus stationary u n t i l the disk came around to i t , at which time they started to track the target. At the end of the t r i a l , E called "STOP", the Ss then had to raise the stylus as fast as possible, put i t down beside the rotor, turn the turnta-ble off by flipping the starting switch, and then return the disk to i t s starting position.. The S then turned his back to the apparatus and ver-bally counted backwards from a given number (from 1000 to 100) by threes u n t i l the "GET READY" signal was again given at which time S again put the tip of the stylus on the right side of the turntable,- 180° from the target. The Ss were asked to perform their best at a l l times. No pre-practice on the task was allowed. No knowledge.of results were given during the experiment and the Ss were never allowed to see the clock or their recorded scores. S t a t i s t i c a l Analysis An analysis of variance was employed to determine i f there were any differences between the total MP and DP groups for ISs, PSs, and FSs: Each analysis of variance partitionel the total sum of squares into a main effects of Practice Schedules and an error terms of Subjects within Practice Schedules. To test differences among the subgroups i n relation to the ISs, PSs, FSs and RSs, an analysis of variance for a factorial design was uti l i z e d . This design resulted in obtaining the two main effects of ab i l i t y levels and practice schedules as well as the interaction bet-ween these two variables. CHAPTER IV RESULTS AND DISCUSSION Results P r o b a b i l i t y Level. For a l l s t a t i s t i c a l analyses, a 5% l e v e l of s i g n i f i c a n c e was used. T o t a l Group Comparisons. The mean performance curves f o r MP and DP conditions over the two p r a c t i c e sessions are presented i n F i g . 2. Both groups exhibited considerable, differences i n the form of t h e i r cur-ves on Day 1 of p r a c t i c e . While the performance curve f o r the DP group i s negatively accelerated, the curve f o r the MP group shows a very rapid improvement during the early t r i a l s , l e v e l s o f f i n l a t e r t r i a l s , and then begins to r i s e very slowly. These curves are s i m i l a r to those usually obtained with MP and DP schedules on the rotary pursuit task (6). There was,,in the case of DP, a small loss i n p r o f i c i e n c y at the s t a r t of ses-sion two. The MP group shows considerable reminiscence and an i n i t i a l post-rest warm-up e f f e c t . The means and standard deviations f o r the MP and DP groups f o r the various conditions are l i s t e d i n Table IV. TIME ON TARGET IN SECS. 37 TABLE IV MEANS AND STANDARD DEVIATIONS IN SECS. OF THE TWO MAIN GROUPS FOR THE VARIOUS CONDITIONS (N = 30 Ss i n each group). PERFOR-INITIAL MANCE FINAL FINAL REMINI-' SCORE SCORE SCORE 1 SCORE 2 SCENCE GROUPS IS PS F S 1 FS 2 SCORE RS DISTRIBUTED Mean 5.25 17.78 18.33 22.17 0.55 PRACTICE S.D. 3.58 4.44 2.83 3.27 3.20 MASSED Mean 6.34 12.53 16.80 22.07 4.27 PRACTICE S.D. 3.31 3.17 2.34 2.71 2.77 Table IV shows that the IS for the MP group was somewhat above that of the DP group. An analysis of variance revealed that t h i s difference was not s i g n i f i c a n t (Table V). TABLE V ANALYSIS OF VARIANCE FOR THE INITIAL SCORE SOURCE OF MEAN PROBA-VARIATION SQUARE BILITY PRACTICE , SCHEDULES 1 17.97 1.51 ^ .05 SUBJECTS within PRACTICE SCHEDULES 58 11.88 TOTAL 59 1. An F - r a t i o of 4.02 was required f o r s i g n i f i c a n c e . I Table IV and F i g . 2 show that the mean PS of the MP group i s considerably smaller than the corresponding score of the DP group. An analysis of variance (Table VI) showed that t h i s difference was s i g n i -f i c a n t . TABLE VI ANALYSIS OF VARIANCE FOR THE PERFORMANCE SCORE SOURCE OF MEAN PROBA-VARIATION SQUARE BILITY PRACTICE SCHEDULES 1 143.62 27.81 < .05 SUBJECTS within PRACTICE SCHEDULES 58 14.87 TOTAL 59 1. An F- r a t i o of 4.02 was required for s i g n i f i c a n c e . A further examination of these PSs indicated that the DP group was on 2 target 41.9% more than the MP group. Following the 24 hrs. interpolated r e s t , performance of the two groups appeared to be r e l a t i v e l y equal (Table IV and F i g . 2), except on the f i r s t t r i a l s where a c e r t a i n amount of warm-up decrement was observed. As a r e s u l t , a s i g n i f i c a n t difference between DP and MP was found between the groups f or FS^ (Table VII) with the DP-'*s FS^ being greater than that of MP. (2) The s u p e r i o r i t y of one group over an other group i n % i s equal to: greatest score - lowest score X 100 lowest score TABLE VII ANALYSIS OF VARIANCE FOR FS, SOURCE OF VARIATION df MEAN SQUARE PROBA-BILITY PRACTICE SCHEDULES SUBJECTS within PRACTICE SCHEDULES TOTAL 58 59 34.98 6.78 5.15 < .05 1. An F-r a t i o of 4.02 was required for s i g n i f i c a n c e . By the end of the second day of p r a t i c e , however, the dif f e r e n c e bet-ween these groups disappeared. An analysis of variance on FS^ (Table VIII) revealed that the Ss i n both groups learned the same amount i n that a nonsignificant F was achieved. TABLE VIII ANALYSIS OF VARIANCE FOR FS, SOURCE OF VARIATION df MEAN SQUARE PROBA-BILITY PRACTICE SCHEDULES SUBJECTS within PRACTICE SCHEDULES TOTAL 58 59 0.15 8.89 0.02 > ..05 1. An F-r a t i o of 4.02 was required f o r s i g n i f i c a n c e . Subgroup Comparisons. Figure 3 presents the performance curves throughout the training sessions for the 4 subgroups trained under either the MP or DP schedules. The performance curves appeared to have the same general characteristics as those obtained for the total MP and DP groups. The ISs, PSs, FSs and RSs obtained for each subgroup are listed in Table IX. TABLE IX MEANS AND STANDARD DEVIATIONS IN SECS. OF EACH SUBGROUP FOR THE VARIOUS CONDITIONS (N = 10 Ss in each group) GROUPS PERFOR- REMINI-INITIAL MANCE FINAL FINAL SCENCE SCORE SCORE SCORE 1 SCORE 2 SCORE IS PS FSj^ FS 2 RS Mean Low Abil i t y S.D. DP Mean High Ability S.D. 1.74 13.76 16.29 19.45 2.53 0.61 4.00 2.51 3.00 3.25 9.53 20.89 19.23 23.42 -1.67 2.24 3.48 2.28 1.79 3.06 Mean Low Abil i t y S.D. MP Mean High Ability S.D. 3.32 11.46 16.08 20.65 4.62 1.15 1.60 1.74 2.04 2.86 10.30 15.21 18.04 24.20 2.83 2.18 3.37 2.13 2.15 2.96 T R I A L S FIGURE 3: Day 1 and Day 2 performance curves for the 4 subgroups as a function of their i n i t i a l a b i l i t y level on the pursuit rotor. (N = 10 in each group). Since the interaction was a direct test of the hypothesis that performance and learning for low-ability Ss would be hindered to a greater extent under MP when compared to high-ability Ss under the same practice schedule, this was the only component of the total analysis of variance that was tested for s t a t i s t i c a l significance i n this particular analysis. Differences between the total groups i n terms of distribution of practice were dealt with i n a previous analysis. The results of the analysis on the ISs of the 4 subgroups revealed no significant F-ratios for the interaction of Practice Schedules and Abi-l i t y Levels (Table X), which indicated that the subgroups within each prac-tice schedule were s t a t i s t i c a l l y equal at the beginning of practice. TABLE X ANALYSIS OF VARIANCE FOR THE INITIAL SCORE OF THE FOUR SUBGROUPS SOURCE OF VARIATION df MEAN SQUARE F PROBA-BILITY PRACTICE SCHEDULES (PS) 1 13.74 4.80 < .05 ABILITY LEVELS (AL) 1 545.23 190.46 < .05 PS X AL 1 1.63 0.57 > .051 SUBJECTS (PS, AL) 36 2.86 1. An F-ratio of 4.11 was required for significance. An analysis of variance of the PSs revealed no significant ef-fects for the interaction of Practice Schedule by Abi l i t y Levels (Table XI). Despite this nonsignificant F, TABLE XI ANALYSIS OF VARIANCE FOR THE PERFORMANCE SCORE OF THE FOUR SUBGROUPS SOURCE OF VARIATION df MEAN SQUARE F PROBA-BILITY PRACTICE SCHEDULES (PS) 1 158.94 15.12 < .05 ABILITY LEVELS (AL) 1 295.80 28.14 < .05 PS X AL 1 28.56 2.72 > .051 SUBJECTS (PS, AL) 36 10.51 1. An F-ratio of 4.11 was required for significance. at this stage of practice the high-ability DP group was on target 37.3% more of the time than the high-ability MP group, while the corresponding figure for the low-ability subgroups indicated that DP was 20% superior. The analysis of variance for FS^ failed to show a significant interaction between the two main effects (Table XII). TABLE XII ANALYSIS OF VARIANCE FOR FS;L OF THE FOUR SUBGROUPS SOURCE OF VARIATION df MEAN SQUARE F PROBA-BILITY PRACTICE SCHEDULES (PS) 1 4.87 1.02 > .05 ABILITY LEVELS (AL) 1 60.12 12.62 < .05 PS X AL 1 2.44 0.51 > .051 SUBJECTS (PS, AL) 36 4.77 1. An F-ratio of 4. 11 was required for significance. A similar analysis of FS 2 again revealed no significant interaction (Table XIII). TABLE XIII ANALYSIS OF VARIANCE FOR FS 2 OF THE FOUR SUBGROUPS SOURCE OF VARIATION df MEAN SQUARE F PROBA-BILITY PRACTICE SCHEDULES (PS) 1 9.92 1.90 > .05 ABILITY LEVELS (AL) 1 141.49 27.03 < .05 PS X AL 1 0.45 0.09 > .051 SUBJECTS (PS, AL) 36 5.23 1. An F-ratio of 4. 11 was required for significance. Reminiscence Scores, An examination of T&ble IX revealed that the MP group reminisced 7.5 times more,than the DP group. This d i f f e -rence was s t a t i s t i c a l l y significant since the F value for the effect of practice schedules exceeded the c r i t i c a l value (Table XIV). TABLE XIV ANALYSIS OF VARIANCE FOR REMINISCENCE SCORES OF THE FOUR SUBGROUPS SOURCE OF VARIATION df MEAN SQUARE F PROBA-BILITY PRACTICE SCHEDULES (PS) 1 108.19 11.72 < .051 ABILITY LEVELS (AL) 1 89.21 9.67 < .051 PS X AL 1 14.30 1.55 > .05 SUBJECTS (PS, AL) 36 9.23 1. An F-ratio of 4 .11 was required for significance. Further examination of RSs in Table IX revealed that low-ability Ss re-minisced 5 times more than high-ability Ss., This difference was also s t a t i s t i c a l l y significant i n that a significant F was achieved for dif f e -rences in a b i l i t y levels (Table XIV). Finally the analysis of the inter-action between the two main effects for the RSs failed to show any sta-t i s t i c a l significance (Table XIV). However, although the low-ability Ss under both MP and DP conditions showed reminiscence, an examination of Table IX showed that the low-ability Ss under MP reminisced 82.6% more than l o w - a b i l i t y Ss under DP. On the other hand, examination of FS^ fo r h i g h - a b i l i t y Ss revealed a small decrement i n performance i n d i c a -t i n g that some fo r g e t t i n g had taken place over the rest period. The h i g h - a b i l i t y Ss under MP, while not e x h i b i t i n g f o r g e t t i n g , only showed a small amount of reminiscence. Discussion Since the analysis of variance revealed no s i g n i f i c a n t d i f f e r e n -ce among the i n i t i a l scores of the MP and DP groups, i t was concluded that the i n i t i a l a b i l i t i e s of these groups were approximately the same. Further, i t was assumed that these i n i t i a l a b i l i t i e s would not d i f f e r e n -t i a l l y a f f e c t any subsequent performance scores or f i n a l scores. The present i n v e s t i g a t i o n i n t o the e f f e c t s that MP and DP schedu-les have on motor performance and learning has shown, i n terms of the to-t a l groups, that MP, while considerably i n h i b i t i n g performance, had l i t -t l e or no influence on amount learned. These r e s u l t s are s i m i l a r to those found by past i n v e s t i g a t o r s (3, 13, 24, 31, 59, 66, 69) i n studies dealing with MP vs DP who used the same types of p r a c t i c e schedules as i n the present study ( i . e . constant work i n t e r v a l s and v a r i a b l e rest i n -ter v a l s ) . The s i g n i f i c a n t decrement observed f or the t o t a l MP group's FS-, could be a t t r i b u t e d to warm-up decrement and not to learning ( F i g . 2). This conclusion was reached because the decrement was completely overco-me i n a few t r i a l s and then the performance curve tended to l e v e l o f f . If the immediate post-rest r i s e had been due to a learning e f f e c t the slope of the a c q u i s i t i o n curve at t h i s point would not have been as steep and would have continued to rise over a substantial number of t r i a l s . Warm-up decrement, according to Ammons (6) and Irion (46), refers to the reinstatement of any number of secondary responses, including a t t i -tudinal and postural adjustments, which are adopted by Ss while perform-ing the task. With the introduction of rest the acquired set is p a r t i a l -ly or completely lost. When practice resumes, this set must be re-acquired during the course of practice and i t is this regaining of set which is thought to account for the rapid improvement in the i n i t i a l segment of the post-rest curve. According to Carron (23:63), "Warm-up decrement on the pursuit ro-tor could be an artifact resulting from the i n a b i l i t y of the S to commence tracking immediately" (when practice is resumed). Adams (4) and Barch (15) appear to be the only authors who have attempted to control for this fac-tor by giving, at the beginning of each t r i a l a warning stimulus and then allowing one free revolution before beginning to record time. In privious studies the presence of warm-up decrement under DP was, generally speaking, non-existent. According to Ammons (6), i n DP there i s a learning of "methods" of warming-up, i.e., the more times practice i s resumed, the easier i t is to warm-up. The present results are seen as con-tradicting this view since warm-up decrement was also observed in the DP group. The fact that warm-up decrement occurred in both experimental groups could have been attributed to the length of interpolated rest. Past investigations (6, 36, 63) have usually only given up to 30 minutes rest before resuming practice. Since the present experiment gave 24 hours i n -terpolated rest, both groups could conceivably have forgotten the correct set for pursuit rotor tracking and thus both would need a few t r i a l s to reinstate the appropriate set. 48 By the end of the second day of p r a c t i c e the differe n c e i n FSs between MP and DP had disappeared (Table V I I I ) . This n o n - s i g n i f i c a n t difference indicated that Ss under MP, while t h e i r PSs were considera-b l y lower than the DP Ss, learned as much as did the Ss under the DP schedule. These r e s u l t s are consistent with previous findings (13, 23, 31, 59, 66, 69) which showed that d i s t r i b u t i o n of p r a c t i c e i s a va r i a b l e that a f f e c t s performance and not learning. The r e s u l t s of the subgroup analysis supported the hypothesis which predicted that the PSs f o r high and l o w - a b i l i t y Ss would be hinder-ed under MP conditions. I t was i n t e r e s t i n g to note that the PSs of the h i g h - a b i l i t y Ss under MP showed a 37% decrement when compared to the high-a b i l i t y DP Ss, whereaa* the corresponding diffe r e n c e between the low-a b i l i t y groups showed the MP group to be.only 20% i n f e r i o r . While t h i s i n t e r a c t i o n did not reach s t a t i s t i c a l s i g n i f i c a n c e the trend which sug-gested that MP affe c t e d performance of h i g h - a b i l i t y Ss to a greater extent than l o w - a b i l i t y Ss was exactly opposite to what had been hypothesized. Except f o r the f a c t that these differences were probably caused by sampling error, no further explanations of these r e s u l t s can be given at t h i s time. The second hypothesis of the present study stated that the amount learned f o r i n i t i a l l o w - a b i l i t y Ss would be less under MP than under DP conditions. This hypothesis was not supported since there was no i n t e r -action between p r a c t i c e schedules and a b i l i t y l e v e l s i n terms of amount learned. These r e s u l t s , however, are consistent with those of Farmer (38) who showed p a r a l l e l performance curves f o r groups of d i f f e r e n t i n i t i a l a b i l i t y and supports the assumption of Hull (45) that individual d i f -ferences affect the constants of a behavioral equation but not the ge-neral mathematical form. Parallel performance curves for low and high a b i l i t y Ss has also been observed by Adams (5) and Reynolds and Adams (63). However, compa-rison of the learning curves obtained i n the present study and the ones obtained by Reynolds and Adams (63) is d i f f i c u l t due to the fact that Reynolds and Adams observed considerable decrement between and within sessions which was caused by short interpolated rests between sessions. Further, in Reynolds and Adams' (63) study, groups were compared on the basis of different practice schedules over a l l sessions. Thus their study as well as the studies of Farmer (38) and Adams (5), have been con-cerned exclusively with performance curves and make no inferences about learning. Nevertheless, i t appears that what the above authors found in regard to performance also applies to learning. This i s true because on the f i n a l session on Day 2, the learning curves of the subgroups showed l i t t l e tendency to converge. It appeared that the Ss did not attain the task assymptote but rather attained an assymptote commensurate with their own a b i l i t y . The fact that at the start of practice on Day Two the low-ability MP Ss reminisced to the same level as the low-ability DP Ss was contrary to the results of Marteniuk and Carron (52) who found that low-ability MP Ss learned more than low-ability DP Ss. However, these authors used a method of distributing practice that differed from the present study in that they uti l i z e d a constant i n t e r t r i a l interval while differentia-ting between MP and DP i n terms of the work interval. In the present study the work i n t e r v a l was kept constant and the rest i n t e r v a l was varied. Thus i t would appear that the r e s u l t s of the present study do not contradict the view of Marteniuk and Carron that the relevant issue i n schedules of s k i l l a c q u i s i t i o n i s determining optimum lengths of work rather than determining optimum lengths of i n t e r t r i a l r e s t i n t e r -v a l s . In other words instead of emphasis being placed on the length of the r e s t i n t e r v a l , as has been done i n most studies dealing with the ef-fe c t s of d i s t r i b u t i o n of p r a c t i c e on learning, Marteniuk and Carron ad-vocate systematically varying the work i n t e r v a l while keeping the r e s t i n t e r v a l r e l a t i v e l y constant. In regard to reminiscence the present study found that l o w - a b i l i t y Ss reminisced s i g n i f i c a n t l y more than h i g h - a b i l i t y Ss. Further, the main e f f e c t of MP versus DP was contrary to theory due to the fa c t that the l o w - a b i l i t y DP group showed large amounts of reminiscence and that suppos-edly no temporary work decrement i s b u i l t up during DP and thus no reminis-cence should occur (50). However Eysenck (37) has stated that reminiscence i n the pursuit rotor i s e n t i r e l y due to consolidation rather than being the r e s u l t of d i s s i p a t i o n of I r . Thus i t could be hypothesized that con-s o l i d a t i o n should occur to a greater extent i n l o w - a b i l i t y Ss than i n high-a b i l i t y Ss i n that i n i t i a l l y l o w - a b i l i t y Ss have more chance to p r o f i t from p r a c t i c e . Iiffother words i t i s reasoned that h i g h - a b i l i t y Ss, having already learned the appropriate responses for the pursuit rotor, are working near t h e i r maximum performance l e v e l s and thus p r o f i t very l i t t l e from consolidation. The f a c t that the l o w - a b i l i t y Ss of the present stu-dy reminisced to a greater extent than the h i g h - a b i l i t y Ss lends support to t h i s viewpoint. One exception to Eysenck 1s hypothesis would occur i n a s i t u a t i o n where a h i g h - a b i l i t y group of Ss, having already developed appropriate responses, were fatigued by MP and then given an interpolated r e s t . Un-der these circumstances any reminiscence e f f e c t that occured might be at t r i b u t a b l e to the d i s s i p a t i o n of the fatigue that depressed pre-rest performance. Presumably t h i s would explain why the h i g h - a b i l i t y MP group of the present study showed reminiscence and the h i g h - a b i l i t y DP group d i d not. The above explanation could also be used to explain why the t o t a l MP group reminisced to a s i g n i f i c a n t l y greater extent than the t o t a l DP group. Supposedly the DP group demonstrated reminiscence only due to con-s o l i d a t i o n and the present r e s u l t s i n d i c a t e that t h i s took place primari-l y i n the l o w - a b i l i t y Ss, with the h i g h - a b i l i t y Ss a c t u a l l y d e t r a c t i n g from t h i s e f f e c t because of fo r g e t t i n g . The MP group, on the other hand, had two factors contributing to t h e i r reminiscence. One fa c t o r was at-tri b u t a b l e to consolidation i n much the same way as i n the DP group. How-ever a second f a c t o r caused by fatigue build-up during Day One performance also contributed to the reminiscence e f f e c t . This second f a c t o r probably accounted f o r the larger reminiscence of t o t a l MP group. CHAPTER V SUMMARY AND CONCLUSIONS The purpose of t h i s study was to investigate the e f f e c t s of mas-sed p r a c t i c e (MP) and d i s t r i b u t e d p r a c t i c e (DP) upon motor performance and learning i n groups of d i f f e r e n t i n i t i a l a b i l i t y . Sixty volunteer right-handed male Ss were tested on the Pursuit Rotor. The Ss were stu-dents enrolled i n ph y s i c a l education classes and were naive to the appa-ratus. They were randomly assigned to eit h e r a MP or a DP schedule with the r e s t r i c t i o n that equal numbers appear i n each group. Twenty-two t r i a l s were performed on Day 1 of the experiment by both MP (30 sees. work-5 sees, rest) and DP (30 sees, work-30 sees, rest) groups. The f i r s t two t r i a l s , for a l l Ss, were performed under the DP schedule. The mean of these two t r i a l s was used to determine the i n i t i a l a b i l i t y of each S. On Day 2, following an interpolated r e s t of approximately 24 hrs., a l l Ss performed 20 t r i a l s under the DP schedule. The r e s u l t s were as follows: 1. Massed p r a c t i c e had an i n h i b i t i n g e f f e c t on Day 1 performance i n that the DP group performed s i g n i f i c a n t l y better than the MP group. 2. The reminiscence score ( i n i t i a l score, Day 2, minus f i n a l score, Day 1) for the MP group was found to be s i g n i f i c a n t l y greater than the reminiscence score f o r the DP group. 3. There were no differences, between the MP and DP groups in f i n a l learning a b i l i t y . 4. No significant effects for the interaction of practice sched-ules by a b i l i t y levels was found for Day 1 performance. 5. Reminiscence scores were related to the i n i t i a l a b i l i t y level of the Ss (p <.05). 6. There was no interaction between distribution of practice and i n i t i a l level of a b i l i t y i n terms of learning. From these results the following conclusions can be stated: 1. Fatigue resulting from MP on the pursuit rotor inhibits per-formance but does not affect learning. 2. Fatigue resulting from MP on the pursuit rotor has no d i f f e -rential effect on Ss of different i n i t i a l pursuit rotor a b i l i t y , in terms of both performance and learning. Recommendations 1. To test Marteniuk and Carron's (52) hypothesis, i t would be more ad-vantageous to use a task like those used by Pew (58) or Ammons (9), where the temporal organization of the response components i s well known. Then the effects of fatigue upon performance and learning could be determined more precisely, both quantitatively and qualitatively. 2. Considering the findings that low-ability Ss reminisced more for the particular practice schedules used here, i t would be desireable to inves-tigate what effects greater massed practice would have upon motor perfor-mance and learning. BIBLIOGRAPHY 1. Adams, J. A., "Warm-up Decrement in Performance on the Pursuit Rotor", The American Journal of Psychology, 65(3):404-414, 1952. 2. Adams, Jack A. and Reynolds, Bradley, "Rotary Pursuit Performance as a Function of I n i t i a l Level of Ability", The American Psy- chologist, 7:261, 1952. 3. Adams, J. A. and Reynolds, B., "Effect of Shift in Distribution of Practice Conditions Following Interpolated Rest", Journal  of Experimental Psychology, 47:32-36, 1954. 4. Adams, J. A., "A Source of Decrement in Psychomotor Performance", Journal of Experimental Psychology, 49:390-394, 1955, Cited in 22. 5. 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Categories of Human Learning, 4th Edition, New York: Academic Press, 1964, pp. 243-285. 41. F i t t s , Paul M. and Posner, M. I., Human Performance. Belmont, California: Brooks/Cole, 1967, 162 pp. 42. Grice, G. R. and Reynolds, B., "Effects of Varying Amounts of Rest on Conventional and Bilateral Transfer 'Reminiscence'", Journal  of Experimental Psychology, 44:247-252, 1952. Cited in Eysenck (2). 43. Hearnshaw, L. S., "Temporal Integration and Behavior", Bulletin British Psychology Association, 30:1-20, 1956. 44. Hull, C. L., Principles of Behavior, New York: D. Appleton-Century, 1943. Cited i n Ammons (1). 45. Hull, C. L., "The Place of Innate Individual Differences in a Natural Science Theory of Behavior", Psychological Review, 52:55-60, 1945. 46. Irion, A. L., "The Relation of 'set' to Retention", Psychological Review, 55:336-341, 1948. 47. Keller, F. S., "The Phantom Plateau", Journal Experimental of the Analysis of Behaviour, 1(1):1-13, 1958. 48. Kientzle, M. J., "Properties of Learning Curves Under Varied D i s t r i -bution of Practice", Journal of Experimental Psychology, 36(3): 187-211, 1946. 49. Kientzle, M. J., "Ability Patterns Under Distributed Practice", Jour-nal of Experimental Psychology, 39:532-537, 1949. 50. Kimble, G. A., "An Experimental Test of a Two-Factor Theory of Inhi-bition", Journal of Experimental Psychology, 39:15-23, 1949. 51. Lashley, K. S., The Problem of Serial Order i n Behaviour. In M. L. A. Jeffries (Ed.), Cerebral Mechanism in Behaviour, New York: J. Wiley and Sons, 1951. 52. Marteniuk, R. G. and Carron, A. V., "Efficiency of Learning as a Function of Practice Schedule and I n i t i a l A b i l i t y " , Journal of  Motor Behavior, 2(2):140-148, 1970. 5 3 . McGraw, L. W., "Comparative Analysis of Methods of Scoring Tests of Motor Learning", Research Quarterly, 26(4):440-453, 1955. 58 54. Mednick, Sernoff A., Learning. New Jersey: Prentice-Hall, 1964, 118. pp. 55. Melton, A. W., "The Effect of Rest Pauses on the Acquisition of the Pursuit meter Habit", Psychological Bulletin, 38: 740, 1941. Cited i n Ammons (1). 56. Miller, G. A., Galanter, E. and Pribram, K., Plans and the Structure of Behavior, New York: Holt, Rinehart and Winston, 1960, 226 pp. 57. Pew, Richard W., Temporal Organization i n Skilled Performance. Un-published Doctoral Thesis, University of Michigan, 1963. 58. Pew, Richard W., "Acquisition of Hierarchical Control Over the Tem-poral Organization of a S k i l l " , Journal of Experimental Psycho- logy, 71(5):764-771, 1966. 59. Pouliot, Jacques, "The Effects of Massed vs Distributed Practice in the Learning and Retention of a Motor Task", Unpublished Term Paper, University of British Columbia, B. C., 1969. 60. Pouliot, Jacques, " S k i l l s Acquisition and the Temporal Organization in Skilled Performance", Unpublished Term Paper:. P.E. 568, University of British Columbia, 1970. 61. Reed, H. B., "The Influence of Training on Changes in Variability in Achievement", Psychology Monograph, 51:14- 1931. 62. Reynolds, R. and Adams, J. A., "Effects of Distribution and Shift in Distribution of Practice Within a Single Training Session", Jour- nal of Experimental Psychology-46:137-145, 1953. 63. Reynolds, Bradley and Adams, J. A., "Psychomotor Performance as a Function of I n i t i a l Level of Ability", The American Journal of  Psychology, 67(2):268-277, 1954. 64. Simon, H. A. and Kotovsky, K., "Human Acquisition of Concepts for Sequential Patterns", Psychological Review, 70:534-546, 1963. 65. Simonson, E. and Brozek, J., "Flicker Fusion Frequency. Background and Applications", Physiology Review, 32:349-378, 1952. Cited in Welford (10). 66. Singer, Robert N., "Massed and Distributed Practice Effects on the Acquisition and Retention of a Novel Basket-ball S k i l l " , Re- search Quarterly, 36(l):68-77, 1965. 67. Singer, Robert N., Motor Learning and Human Performance: An Appli- cation to Physical Education S k i l l s , New York: Macmillan, 1968, 354 pp. 59 68. Snoddy, G. S., "Evidence f o r a Universal Shock Factor i n Learning", Journal of Experimental Psychology, 35:403-417, 1945. Cited i n Ammons (1). 69. Stelmach, George E., " E f f i c i e n c y of Motor Learning as a Function of I n t e r t r i a l Rest", Research Quarterly, 40(1):198-202, 1969. 70. Vince, M. A., "Corrective Movements i n a Pursuit Task", Quarterly Journal of Experimental Psychology, 1:84-103, 1948. 71. Welfo.rd, A. T., Fundamentals of S k i l l , Toronto: Methuen and Co., 1968, 426 pp. 72. Woodrow, Herbert, "The E f f e c t of P r a c t i c e on Test Inter-Correlations", The Journal of Educational Psychology, 29(8):561-572, 1938. 73. Woodrow, Herbert, "The E f f e c t of P r a c t i c e on Groups of D i f f e r e n t I n i t i a l A b i l i t y " , Journal of Educational Psychology, 29:268-278, 1938. 74. Woodrow, Herbert, "The Relation Between A b i l i t i e s and Improvement With P r a c t i c e " , Journal of Education Psychology, 29:215-230, 1938. 75. Woodworth, Robert S. and Schlosberg H., Experimental Psychology, Revised e d i t i o n , New York: Holt Rinehart and Winston, 1954, 948 pp. 76. Wooworth, R. S., Dynamics of Behavior. New York: Henry Holt, 1958. 77. Zeaman, David and Kaufman H., "I n d i v i d u a l Differences and Theory i n a Motor Learning Task", Psychological Monographs: General and  Applied. 69(6) whole 391:1-15, 1 1955. A P P E N D I X A P P E N D I X "A" INSTRUCTIONS The object of the task is to track the metal disk on the rotor by keeping the metal stylus tip in contact with i t for as long as pos-sible during each t r i a l . You w i l l hold the wooden handle of the stylus i n your preferred hand with a tennis-type grip as demonstrated by the experimenter (look at the experimenter). The following must be done with an easy, relaxed, swinging arm movement and no extra pressure must be put on the stylus tip i n any way. You w i l l start by holding the stylus on the opposite side from the target as demonstrated by the experimenter (look at the experimen-ter). Before starting the turntable, I w i l l say "READY", then hold the stylus stationary until the disc comes around to i t , at which time you w i l l start to track the target. At the end of the t r i a l , I w i l l say "STOP" and you w i l l immediately take the stylus off the rotor, put i t down beside the rotor, turn the turntable off, and then return the disk to i t s starting position by rotating the turntable i n a clockwise direc-tion. You w i l l then turn your back to the apparatus and start counting backwards by three from the number that I w i l l c a l l u n t i l the "GET READY signal. Then you w i l l repeat the whole procedure for a new t r i a l . You w i l l find that i t is d i f f i c u l t at the beginning to track the target but you must do your best to stay on the target as long as you can. Remember i t is the time that the stylus is i n contact with the target that determines how well you do. Now I w i l l ask you to t e l l me verbally what you have to do to see i f you understood the instructions. (After S had finished explain-ing his task and E correcting him when necessary, E then asked, "Do you have any questions?" A P P E N D I X "B" RAW DATA The following data represent the time on target in seconds for each S, on each t r i a l . The f i r s t four rows from the top are the data for S^, the f o l -lowing four for etc. For each S, the f i r s t two rows read by a format of (11F4.2) re-present his performance, on each t r i a l , on Day One; the second two rows read by a format of (10F4.2) represent his performance on each t r i a l , on Day Two. 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