Technical Report 431 (.,2

EFFECTS OF PRESENTATION- AND TEST-TRIAL TRAINING

ON MOTOR ACQUISITION AND RETENTION

Joseph D. Hagman

00O TRAINING TECHNICAL AREA

f U. S. Army

<:1l Research Institute for the Behavioral and Social Sciences

I~J

January 1980

Approved for public release, distribution unlimited.

80 7 1-045 0
U. S. ARMY RESEARCH INSTITUTE

FOR THE BEHAVIORAL AND SOCIAL SCIENCES

A Field Operating Agency under the Jurisdiction of the

Deputy Chief of Staff for Personnel

FRANKLIN A. HART

JOSEPH ZEIDNER Colonel, US Army

Technical Director Commander

NOTICES

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P9.I The findings in this report are not to be construed as en official Depoartlmlent of the Army position. unless so designated by other authorized documents.
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FFECTS OF I RESENTATION- AND TEST-TRIAL TRAINING

PN OTOR ACQUISITION AND RETENTION*

6. PERFORMING ORG. REPORT NUMBER

7. AUTHOR(&) 8. CONTRACT OR GRANT NUMBER(e)

Josep D./Hagman

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19. KEY WORDS (Continue on fev'ers* side if necessary and identify by block numiber)

Training Repetition

Motor Skills Presentation Trials

Learning Test Trials

Retention Linear Positioning

20. ABSTRACT (Contnde on reverse side Of necessary and identify by block numnber)

Thi o~ari.-t1examined the relative effects of three different training methods on the acquisition and retention of a positioning motor task. Three independent

groups of subjects (N = 15 per group) performed three training trial cycles con- sisting of six trials each. Training methods differed in their emphasis on presentation (p) and test (t) trials during each cycle. For one group, a cycle

consisted of three p- and t-trials administered in alternation. For another

group, the first five trials of each cycle were p-trials and the sixth was a -

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t-trial. For the last group, the first trial was a p-trial and the next five

were t-trials. Group acquisition performance was compared at the last trial

of each cycle while retention was compared 3 mn. and 24 hr. after acquisition.

Absolute error scores indicated that acquisition and short-term retention were

best when training emphasized p- and t-trial alternation and p-trial repetition

within cycles, whereas long-term retention was best when training stressed

t-trial repetition. Results suggest that testing is an effective way to enhance

long-term retention of motor skill. This enhancement could be realized by

changing the emphasis of training from presentation to testing without added

expenditures in training time, money and personnel. If, instead of long-term

retention, the goal is rapid acquisition and short-term retention, training

methods which emphasize either alternation of presentation and testing or

repeated presentation would be most effective.

j.For

/TI

~!

Un class if~ *

i tCUfITy CLASSIFICATION OF THIS PAGEtIRU DUE. NLIIem
Technical Report 431

EFFECTS OF PRESENTION- AND TEST-TRIAL TRAINING

ON MOTOR ACQUISITION AND RETENTION

Joseph D. Hagman

Submitted by.

Milton S. Katz, Chief

TRAINING TECHNICAL AREA

Approved By:

E. Ralph Dusek

PERSONNEL AND TRAINING

RESEARCH LABORATORY

U.S. ARMY RESEARCH INSTITUTE FOR THE BEHAVIORAL AND SOCIAL SCIENCES

5001 Eisenhower Avenue, Alexandria, Virginia 22333

Office, Deputy Chief of Staff for Personnel

Department of the Army

January 1980

Army Project Number Motor Skills Training

2T1611O1A91B

04red for oublic n1gm: distribution~ unlimited.
ARI Research Reports and Technical Reports are intended for sponsors of

R&D tasks and for other research and military agencies. Any findings ready

for implementation at the time of publication are presented in the last part

of the Brief. Upon completion of a major phase of the task, formal recommendations for official action normally are conveyed to appropriate military

agencies by briefing or Disposition Form.

iv

. .".. ..
FOREWORD

The Training Technical Area of the Army Research Institute for the

Behavioral and Social Sciences (ARI) conducts research in support of the

systems engineering concept of training. A major objective of this

research is to develop the fundamental data and technology necessary to

field integrated systems for improving individual job performance. Such

systems include Skill Qualification Testing (SQT), job performance aids,

and training courses both in schools and in the field.

This report is one of a series on specific topics in the area of

skill acquisition and retention. In response to requirements by the

Deputy Chief of Staff for Training of the Army Training and Doctrine

Command (TRADOC), the long-term research goal is to develop methods for

predicting proficiency loss for all types of skills and for determining

effective training procedures for reducing this loss. The present work

represents a basic research effort completed by ARI personnel under Army

Project 2TI611OIAl9B.

(JO EPH ZE ER

'Shnical Director

v

A V
EFFECTS OF PRESENTATION- AND TEST-TRIAL TRAINING ON MOTOR ACQUISITION

AND RETENTION

BRIEF

Requirement:

To evaluate the relative effectiveness of three motor task training

methods which differ in their emphasis on presentation and test trials.

Procedure:

Tnree groups of 15 participants received 18 training trials on a

simple motor task. The 18 training trials were divided into three

cycles of six trials, containing both presentation and test trials.

During presentation trials, participants studied the criterion movement

to be learned by moving a sliding mechanism along a linear track for a

distance of 250 mm before contacting a mechanical stop. During test

trials, they tried to recall the criterion movement by moving the slide

for the same distance without the aid of the mechanical stop.

In the acquisition part of the experiment, the sequence of presentation

and test trials performed within cycles differed for each training

group. For the STANDARD group, a cycle consisted of three presentation

and three test trials administered in alternation. For the PRESENTATION

group, the first five trials of each cycle were presentation trials and

the sixth was a test trial. For the TEST group, the first trial was a

presentation trial and the next five were test trials. In the retention

part of the experiment, all participants performed a single test trial

at both 3 minutes and 24 hours after the last training trial.

Findings:

The three training methods had different effects on acquisition and

retention. Absolute (unsigned) error scores indicated that acquisition

and short-term (3 minute) retention were best for the STANDARD and

PRESENTATION groups, whole long-term (24 hour) retention was best for

the TEST group.

Utilization of Findings:

Testing is an effective way to enhance long-term-retention of motor

skills. This enhancement can be achieved by changing the emphasis in

training from presentation to testing, without the need for additional

training time, money or personnel. If instead of long-term retention,

the goal is rapid acquisition and short-term retention, training which

vii I -

p" NA NOT1UL
emphasizes either alternation of presentation and testing or repeated

presentation would be most effective. Additional research is needed to

determine how well these laboratory results will generalize to actual

military motor skills.

viii
EFFECTS OF PRESENTATION- AND TEST-TRIAL TRAINING ON MOTOR ACQUISITION

AND RETENTION

CONTENTS

Page

INTRODUCTION...........................

METHOD............................3

Subjects..........................3

Apparatus. .......................... .. .. ...... 4

Design...........................4

Procedure.........................5

RESULTS...........................5

Acquisition........................7

Retention........................10

DISCUSSION...........................11

CONCLUSIONS.........................14

REFERENCES...........................17

DISTRIBUTION.........................21

ix
LIST OF FIGURES

Page

Figure 1. Trial sequence for each training group

(P = Presentation; T = Test) .. ............... 6

2. Mean algebraic error resulting from t-trial

execution by the STANDARD, PRESENTATION and

TEST training groups at acquisition and

retention ........ ........................ 8

3. Mean absolute error resulting from t-trial

execution by the STANDARD, PRESENTATION and

TEST training groups at acquisition and

retention ........ ....................... 9

x
EFFECTS OF PRESENTATION- AND TEST-TRIAL TRAINING ON MOTOR ACQUISITION

AND RETENTION

INTRODUCTION

A long-term goal of the Army is the development of effective methods

for training all types of Army-related skills. Of constant interest is

the question of which specific training methods promote the highest

levels of skill acquisition and retention. Much of the theoretical and

empirical information relating to this question has been derived from

the conduct of basic research experiments in the areas of verbal and

motor learning. In these experiments, training has involved the execution of both presentation (p) and test (t) trials. During p-trials,

subjects study information to be learned and during t-trials they attempt

to recall it from memory. The number and sequential arrangement of pand t-trials performed during training has depended on the particular

method adopted. The standard training has involved the alternation of

p- and t-trials (e.g., Tulving, 1967; Wrisberg & Schmidt, 1975) but

other methods which emphasize either p- or t-trial repetition also have

been used (Adams & Dijkstra, 1966; Bilodeau & Bilodeau, 1958; Hogan &

Kintsch, 1971).

The Army's question of which training method most effectively promotes

acquisition and retention is difficult to answer because relevant theories

make conflicting predictions regarding the role of p- and t-trials. For

example, from a traditional learning theory viewpoint, where p-trials

are seen as having an effect similar to reinforcement, training methods

which repeat p-trials should be more effective than those which repeat

t-trials. Repetition of t-trials reduces the number of reinforcement

opportunities, and therefore, should retard both acquisition and retention.

From a contemporary cognitive viewpoint, however, information processing

activities such as recall and internal generation of to-be-learned items

are considered important aspects of acquisition and retention (Bjork,

1975; Dosher & Russo, 1976). Because t-trials provide an opportunity to

perform these activities on the information studied during p-trials,

training methods which repeat t-trials should be more effective than

those which repeat p-trials.

A look at empirical evidence related to the issue of which training

methods are most effective also reveals inconsistencies. Most of this

evidence has come from research in verbal task learning. Here, the

relative effects of p- and t-trial repetition during training have been

of interest for a long time (Gates, 1917; Hellyer, 1962; Raffel, 1934)

but have only recently received systematic investigation. In general,

investigators have found that training methods which emphasize p-trial

repetition produce superior acquisition (Hogan & Kintsch, 1971; Thompson,

Wenger & Bartling, 1978, Exp III) whereas those which emphasize t-trial

repetition produce superior retention (Allen, Mahler & Estes, 1969;

Hogan & Kintsch, 1971; Rosner, 1970; Thompson, et al., 1978, Exp II;)

1]
In contrast, the pattern of results for motor task learning has been

somewhat different. Generally, emphasis on p-trial repetition during

training has enhanced both acquisition (Holding & Macrae, 1964) and

retention (Adams & Dijkstra, 1966), but emphasis on t-trial repetition

has not. Although both subjective recall consistency and error detection

ability have developed as a function of repeated t-trials (Newell, 1974;

Seashore & Bevelas, 1941) movement accuracy has not been found to improve

(Holding & Macrae, 1964; Newell, 1976, Exp I; Thorndike, 1927) except

after considerable prior t-tr il repetition (Newell, 1976, Exp I and

III). In fact, accuracy typically has decreased during both acquisition

and retention when t-trials have been repeated during training (Bilodeau

& Bilodeau, 1958; Duffy, Montague & Laabs, 1975).

Thus, training methods stressing p-trial repetition have had relatively

consistent beneficial effects on both motor and verbal task performance,

especially at acquisition. In contrast, methods stressing t-trials have

positively affected verbal task retention but have negatively affected

both motor task retention and acquisition. Specific reasons for this

differential effect of t-trial repetition on verbal and motor task

performance are difficult to pinpoint because of the many differences

that exist between the two areas of research. One suggested reason,

however, centers around the difference in information processing activity

required of subjects at p- and t-trials during motor and verbal task

training. In verbal task training, p- and t-trials are procedurally

distinct and require dissimilar information processing activities.

During p-trials, items to be learned are shown to subjects for study.

During t-trials, these items are removed and subjects are required to

recall them from memory. In motor task training, however, p- and ttrials are procedurally similar and require very similar information

processing activities. At p-trials, subjects attempt to recall a

criterion movement from memory. This recall attempt is followed by

knowledge of results regarding recall accuracy, typically in visual or

verbal form. At t-trials, subjects are also required to recall the

criterion movement but knowledge of results is not provided. Thus,

motor task training requires recall at the execution of both p- and ttrials whereas verbal task training requires study at p-trials and

recall at t-trials. To the extent that study and recall processes have

been found to differentially affect verbal acquisition and retention

(e.g., Hogan & Kintsch, 1971), it is necessary to create a common

procedural environment in motor task training such that process effects

on motor acquisition and retention can also be examined.

Another suggested reason for the different effects of t-trial

repetition on verbal and motor task performance stems from the difference

in retention interval lengths used to investigate the retention of each

type of task. For example, the effects of repeated t-trial training on

verbal task retention have been examined primarily using long-term

retention intervals (e.g., Allen, et al., 1969) whereas short-term

2
retention intervals typically have been used in examining t-trlal effects

on motor task retention (Duffy, et al., 1975; Stelmach & Bassin, 1971).

Because the effect of repeated t-trials on motor retention may vary with

the length of the interval as it does for verbal retention (Hogan &

Kintsch, 1971; Thompson, et al., 1978, Exp 111), meaningful comparisons

between t-trial repetition effects on verbal and motor retention have

been difficult to make.

The present experiment was designed to examine the relative effectiveness of different motor training methods under acquisition and retention

conditions similar to those used in verbal training studies. The general

approach was to allow either repetition or alternation of p- and ttrials prior to a given t-trial during training and to compare the

effects of such manipulation on both the acquisition and retention of a

linear positioning movement.

In order to create acquisition and retention conditions similar to

those used in verbal task training, the present experiment differed from

other motor task training experiments in three ways. First, training

procedures were designed so that subjects were required to study the

criterion movement to be learned during p-trials and to recall it from

memory during t-trials. This was accomplished by using a constrained

movement procedure at p--trial execution and a preselected movement

procedure at t-trial execution. Constrained p-trial movements were

performed with the aid of a mechanical stop. Use of the stop ensured

that subjects would study the criterion movement. Preselected t-trial

movements, on the other hand, were performed without the aid of the

mechanical stop. Removal of the stop ensured that subjects would have

to recall the to-be-learned movement from memory. Second, p- and ttrial training effects were measured over both short- and long-term

retention intervals. This allowed for the examination of the potential

interaction between training method and retention interval length and

permitted a more meaningful comparison of repeated t-trial training

effects on verbal and motor retention. Third, training was restricted

to the kinesthetic cue of distance. Although multiple cues underlie the

recall of positioning movements (Hagman & Williams, 1977; Gundry, 1975),

training was restricted to the specific cue of distance to prevent the

possibility of unsystematic subject selection of individual cues and the

possibility that certain cues might react differently to p- and t-trial

repetition because of their differential retention characteristics

(Laabs, 1973; Posner, 1967).

METHOD

Subjects

Forty-five government employees (27 men and 18 women) volunteered to

serve as subjects in the experiment. Forty-three were members of the

professional and clerical staff of the Army Research Institute and two

were professionals affiliated with other agencies.

3
Apparatus

Movements were made from left to right using a metal slide which

slid along two stainless steel rods 35 in. (88.90 cm) in length. Two

Thompson Ball Bushings supported the slide on the rods which were mounted

in parallel on a metal frame 4.25 in. (11.00 cm) apart and located 11

in. (27.94 cm) above the base of the frame. The base rested on a

standard table top 31 in. (78.74 cm) from the floor. A second slide was

used to stop p-trial movements. This slide could be securely positioned

by the experimenter along the entire length of the steel rods. Displacement of each slide rotated a separate 10-turn variable voltage precision

potentiometer which was mounted on one side of the frame. The position

of each slide corresponded to a specific voltage level at the potentiometer

and was displayed by a digital voltmeter. The displayed voltage corresponded

to millimeters and was accurate to within + 1 mm. Additional apparatus

included a chin rest to control head movements and body position;

earphones through which subjects heard tape-recorded procedural instructions;

and a blindfold to prevent subjects from using visual cues during the

experiment.

Design

The experiment contained an acquisition and a retention segment as

shown in Figure 1. The acquisition segment consisted of 18 training

trials divided into three cycles of six trials each. Each cycle contained

p- and t-trials. P-trials were constrained movements during which

subjects contacted a mechanical stop after moving the to-be-learned

distance of 250 mm. T-trials were preselected movements during which

subjects attempted to recall the studied distance without the presence

of the mechanical stop. The sequence of p- and t-trials within cycles

differed for each of three training groups. For Group STANDARD, a cycle

consisted of three p- and three t-trials administered in an alternating

sequence. For Group PRESENTATION, the first five trials in each cycle

were p-trials and the sixth was a t-trial. For Group TEST, the first

trial was a p-trial and the next five were t-trials. Training was such

that a t-trial occurred every sixth trial for all three groups. As a

result, a 3x3 mixed factorial design was used to examine acquisition

performance with the between-subjects variable being Groups (STANDARD,

PRESENTATION, TEST) and the within-subjects variable being Trials (6,

12, 18).

The retention segment of the experiment consisted of a single ttrial performed at both 3 min and 24 hr after Trial 18 of acquisition.

Performance at Trial 18 was used to evaluate immediate recall accuracy

and incorporated into a 3x3 mixed factorial design used to analyze

retention. In this design, the between-subjects variable was Groups

(STANDARD, PRESENTATION, TEST) and the within-subjects variable was Time

4
of Recall (Immediate, 3 min, 24 hr). Fifteen subjects were assigned

randomly to each of the three groups with the constraint that each group

contain the same number of men and women.

A total of 20 movements were performed during the experiment. Each

began from a different starting position which varied between 0 and 380 mm from the left end of the apparatus in increments of 20 mm. Variation

of movement starting position prevented the use of stopping location as an aid to learning distance. Three random starting position sequences were developed. Five subjects in each group were trained under one of

the three sequences.

Procedure

At the beginning of the experiment, all subjects were instructed to

learn and remember distance. They were shown a written copy of the

entire p- and t-trial command sequence appropriate to their training

group and told tile meaning of each command that they would he hearing.

The p-trial command was "Movement" and the t-trial command was "Recall

Movement." Each of these commands was preceded by "Ready" and followed

by "Rest." At "Ready" the experimenter graspeQ the subject's right hand

and placed it on the handle of the slide. Five seconds later, subjects

heard either "Movement" or "Recall Movement" depending on their training

group. At the "Movement" command, they moved the slide across the

linear track at a moderate pace until contacting the mechanical stop.

At the "Recall Movement" command, they moved the slide until they felt

that they had recalled the correct distance. Five seconds were allowed

for execution of p- and t-trial movements. During this intetval, white

noise was delivered over the earphones to eliminate auditory cuLs

resulting from displacement of the slide. "Rest" marked the start of a 10 sec time interval during which subjects removed their hand.; from the

slide and placed it in a predetermined resting place on the table. It was during rest periods that the experimenter recorded recall accuracy

to the nearest mm and repositioned either the slide alone or both it and

the mechanical stop in preparation for the next trial. After "Rest"

subjects heard "Ready" and the sequence of commandm for the next trial

began. During the retention segment of the experiment, intervals of 3

main and 24 hr were inserted between "Rest" and "Ready." Subjects were asked not to count while moving the slide and were shown the approximate

movement speed (125 mm/sec) desired by the experimenter. Prior to

making the first movement subjects donned their blindfold and earphoiic -

; and were then given an opportunity to move the slide and get a feel for

its basic movement characteristics.

RESULTS

Algebraic (signed) and absolute (unsigned) error scores were recorded

for each t-trlal performed during the acquisition and retentton segments of the experiment. The scores for each segment were aralyzefd separatelY.

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Acquisition

Mean algebraic and absolute error scores for acquisition t-trials

are shown on the left in Figures 2 and 3. Although each figure depicts

the mean scores of all t-trials performed during acquisition, initial

statistical analyses were restricted to the scores on those t-trials

which coincided temporally for all three training groups, i.e., trials

6, 12, and 18. These scores were analyzed using a Groups (STANDARD,

PRESENTATION, TEST) by Trials (6, 12, 18) mixed factorial analysis of

variance.

Analysis of algebraic error revealed only a significant main effect

of Groups, F (2,42) = 3.62, p < .05. Based on this significant F-value,

individual comparisons were made using the least squared difference

(LSD) method (Carmer & Swanson, 1973). All comparisons had a rejection

region of .05. They revealed that TEST group performance was different

from that of the STANDARD, LSD (42) = 20.98, and PRESENTATION groups,

LSD (42) = 19.80, but that the performance of these latter two groups

did not differ. The STANDARD and PRESENTATION groups displayed a

significant overshooting bias with LSD (42) = 17.58 and 16.40, respectively,

whereas the apparent undershooting tendency of the TEST group was not

significant. Visual inspection of F'gure 2 reveals that algebraic error

differences were already present between groups on the first t-trial of

the first cycle and remained essentially unchanged throughout acquisition.

Consequently, it could be argued that the obtained differences were

probably a function of preexisting response bias differences present

among the subjects in each training group rather than the result of

differential training. Apart from this apparent response bias difference among groups, no other significant algebraic error effects were

found.

Analysis of absolute error revealed a significant main effect of

Trials, F (2,84) = 4.08, p < .05 and Groups, F (2,42) = 4.48, p < .05.

Individual comparisons indicated that the Trials effect was caused

primarily by a decrease in absolute error between trials 6 and 12, LSD

(84) = 8.11, as the error decrease between trials 12 and 18 was not

significant. The Groups effect was the result of the TEST group having

greater error than either the STANDARD, LSD (42) = 13.17 or PRESENTATION

groups, LSD (42) = 14.29. The error for these latter two groups, however,

did not differ. Thus, the groups which experienced either p-trial

repetition or p- and t-trial alternation during training performed

better than the group which experienced t-trial repetition during training.

Visual inspection of Figure 3 reveals that the curves of the STANDARD

and PRESENTATION groups were similar to one another, while the curve of

the TEST group was slightly above the other two and had a serrated

appearance. This serrated curve of the TEST group reveals that absolute

error tended to increase as t-trials were repeated within each acquisition

trial cycle but that this increase was compensated for by a large decrease

in error between cycles. To determine the reliability of the within7
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cycle error increase, a Cycle (1-3) by Trials (1-5) analysis of variance

was performed on all t-trial scores for the TEST group. As expected,

the Trials effect was significant, F (4,56) = 4.24, p < .05. Individual

comparisons showed that absolute error increased reliably within cycles

and that performance on the last t-trial of each cycle was inferior to

that on the first t-trial of each cycle. This within-cycle error increase

caused by t-trial repetition is consistent with the results of previous

motor (Bilodeau & Bilodeau, 1958; Duffy, et al., 1975) and verbal

learning studies (e.g., Bregman & Wiener, 1970) which also have used

repeated t-trials during training. To examine the between-cycle decrease

in error, group performance was compared before within-cycle error had a

chance to materialize for the TEST group. This comparison required the

use of an additional Groups by Trials analysis of variance. In this

analysis, STANDARD and PRESENTATION group performance at the end of each

cycle, i.e., trials 6, 12 and 18, was compared with TEST group performance

at the beginning of each cycle, i.e., trials 2, 8 and 14. Although the

trials effect was still significant with this analysis, F (2,84) = 4.78,

p< .05, the Groups effect was not. The lack of a Groups effect indicated

that TEST group error was greater than that of the other two groups only

at the end of each cycle after within-cycle error had had a chance to

build up. This build up of within-cycle error, however, was somehow

compensated for by a decrease in error between cycles. Thus, repeating

t-trials during training produced both positive and negative effects on

acquisition. The negative effects took the form of increased withincycle error and the positive effect took the form of decreased betweencycle error. Both of these effects have been reported previously by

verbal researchers (e.g., Izawa, 1970; Tulving, 1967).

Retention

Mean algebraic and absolute error scores obtained during the retention

segment of the experiment are shown on the right side of Figures 2 and

3. Retention was examined using a Groups (STANDARD, PRESENTATION, TEST)

by Retention Interval (Immediate, 3 min, 24 hr) analysis of variance.

Performance at trial 18 was included in the analysis to indicate immediate

recall at the end of acquisition trials.

For algebraic error, no significant effects were found although the

order of group performance present at the end of acquisition was maintained

across retention intervals. For absolute error, a significant Groups by

Retention Interval interaction was found, F (4,84) - 4.10, R < .05. As

shown in Figure 3, this interaction resulted from an increase in error

across retention intervals for the STANDARD and PRESENTATION groups and

a decrease in error for the TEST group. Individual comparisons of

simple effects revealed that at the end of acquisition (trial 18) the

TEST group displayed greater error than either the STANDARD, LSD (84) =

19.00, or PRESENTATION group, LSD (84) = 17.86, and that no difference

existed between the errors of these latter two groups (i.e., TEST >

PRESENTATION = STANDARD). Three minutes after acquisition the only

10
significant change in group performance was an increase in error for the

PRESENTATION group, LSD (84) = 16.07. As a result of this increase, the

TEST and PRESENTATION group scores did not differ 3 min after acquisition

and their average absolute error was greater than that of the STANDARD

group, LSD (84) = 13.83 (i.e., TEST = PRESENTATION > STANDARD). Both

the PRESENTATION and the STANDARD group displayed significant error increases

between 3 min and 24 hr after acquisition, with LSD (84) = 13.45 and

13.40 for each group, respectively. In contrast, TEST group error

decreased significantly over this same time period with LSD (84) = 13.13. As a

result, 24 hr after acquisition TEST group performance was superior to

that of the STANDARD group, LSD (84) = 13.40 which, in turn, was superior

to that of the PRESENTATION group, LSD (84) = 15.80 (i.e., TEST < STANDARD <

PRESENTATION). Thus, emphasis on p-trials during training resulted in

rapid and extensive retention losses, whereas p- and t-trial alternation

enhanced short-term retention while emphasis of t-trial repetition

enhanced long-term retention of movement distance.

DISCUSSION

The three training methods examined in the present research produced

different effects on motor acquisition and retention. During acquisition,

performance improved in the usual negatively accelerated fashion when

training consisted primarily of p-trial repetition or p- and t-trial

alternation. However, when training consisted primarily of t-trial

repetition, performance was characterized by increased within-cycle

error offset by decreased between-cycle error. Because of the way that

performance varied during acquisition when t-trials were repeated, the

relative superiority of the three training methods was a function of

where their performance was compared during acquisition. When comparisons

were made before t-trial repetition had inflated the within-cycle error

of the TEST group, no performance differences were found among the three

groups. When comparisons were made after the TEST group had completed

t-trial repetition, the training methods employing p-trial repetition

and p- and t-trial alternation produced superior acquisition performance.

Of particular interest is the question of why t-trial repetition -

produced both increased within-cycle error and decreased between-cycle

error during acquisition. There are at least two reasons for the

increased error within cycles. First, subjects may have been attempting

to recall an ever-decaying memorial representation of movement distance

established at the execution of an earlier p-trial, and as a result,

their recall accuracy got progressively worse. This notion is consistent

with short-term motor memory research showing that distance information

does decay rapidly and cannot be retained over even short retention

intervals (e.g., Laabs, 1973). Second, within-cycle error could have

increased because t-trial repetition produced interference (Bilodeau &

Bilodeau, 1958). Although t-trials are not intended to interfere with

retention, they usually are different from the criterion movement, and

therefore possess the potential for producing interference (Hlagman,

ii

k .
1978). Assuming a positive relationship between the magnitude of

absolute error and the number of interfering movements performed, increased

within-cycle error could have been a function of the added number of

interfering movements afforded by t-trial repetition. Because both

decay and interference have adversely affected retention of distance in

the past, it is likely that both processes contributed to the withincycle error increases observed in the present experiment. One way to

examine the effect of interference alone would be to perform the same

experiment using a movement cue such as stopping location which is

affected adversely by interference (Hagman, 1978) but not by decay

(Laabs, 1973).

Reasons why t-trial repetition produced such large between-cycle

decreases in error are not readily apparent. Researchers in verbal

learning have suggested that one function of testing via recall is to

enhance a subject's ability to recognize past words recalled (Klee &

Gardiner, 1976). Perhaps, the same effect of testing occurs in motor

learning. After repeated testing attempts, subjects may know more about

their recall performance than those subjects who do not perform repeated

testing. Consequently, subjects in the TEST group may have been better

able to discriminate their recalled distance from that of the criterion

distance and been more capable of making the appropriate adjustments

needed for more accurate recall. Although speculative, the notion that

increased discrimination ability results from t-trial repetition is

consistent with previous motor research (Newell, 1974). In essence, ttrial repetition may serve to potentiate the effect of subsequent ptrials. This type of potentiating effect has been reported to occur in

verbal learning (Izawa, 1970) but has only been hinted at in motor

learning (Bilodeau & Bilodeau, 1958; Henderson, 1977). Thus, additional

research is needed before a firm conclusion can be drawn about the

potentiating effects of t-trial repetition in motor learning. One

approach might be to vary the number of t-trials repeated prior to ptrial execution. If potentiation does occur, one should find that as

the number of repeated t-trials increases performance following a

subsequent p-trial should also increase.

To better examine potentiation effects in motor learning, a task

more difficult than linear positioning should be chosen. This would

reduce the possibility of unwanted ceiling or floor effects influencing

the data. In the present experiment, acquisition performance of the

STANDARD and PRESENTATION groups tended to flatten out both within and

between cycles 2 and 3. Because of this, it was possible that ceiling

effects on accuracy prevented future reduction of errors for these two

groups. TEST group performance, however, was not near the ceiling at

the end of each cycle due to within-cycle error increases, and thus, had

ample room for improvement between cycles. By eliminating any possibility

of ceiling effects differentially affecting group peiformance, potentiation

could be examined more effectively.

12
The different influence of p- and t-trial training methods was most

evident at retention. Forgetting of distance was rapid and extensive

when p-trials were repeated during training. Repetition of t-trials

during training, however, retarded long-term forgetting and actually

produced improvements in recall accuracy over time. Alternation of pand t-trials during training prevented short-term retention losses but

was not as effective a3 t-trial repetition in reducing long-term retention

losses. Apparently, a greater emphasis on t-trial repetition during

training is needed to prevent long-term forgetting of movement distance.

Two questions regarding the retention results need to be discussed.

First, why did repeated t-trial training at acquisition cause superior

long-term retention of movement distance? And second, why did -epeated

t-trial training cause improved retention over time? Although it would

be premature to suggest any definite answers to these questions before

additional research is conducted, some mention of a potential explanatory

concept for each question would seem appropriate at this time.

Consider the first question of why did t-trial repetition produce

superior long-term retention of distance. A potential answer to this

question relies on the distinction between constrained and preselected

movement procedures and the types of information available to subjects

for processing as a result of executing constrained p-trials and preselected t-trials. Investigators have shown that constrained movements

provide subjects with kinesthetic feedback information originating from

muscles and joints (Goodwin, McCloskey & Matthews, 1972; Marteniuk &

Roy, 1972). Preselected movements, on the other hand, not only provide

this kinesthetic feedback but also provide additional information regarding

efferent commands given to the muscles (Jones, 1974). Presumably, for

accurate efferent-command information subjects must know the movement

stopping location in advance (Stelmach, Kelso, & McCullagh, 1976).

Hence, in the present experiment accurate efferent information was

present only under preselected movement procedures. The presence of

efferent information allows subjects to preprogram their recall of

distance (,Jones & Hulme, 1976) and because of this distance is retained

better when performed under a preselected rather than a constrained

movement procedure (Kelso, 1977; Stelmach, Kelso & Wallace, 1975).

Because of the superior retention characteristics associated with preselected movements, subjects may have relied on retention of their

recall performance at t-trials rather than their study performance at ptrials to support later t-trial recall attempts. If long-term retention

of t-trial recall performance improves as a function of t-trial repetition

as might be expected, then the order of group recall error 24 hr after

acquisition would have been as reported (i.e., TEST < STANDARD < PRESENTATION).

One problem with this interpretation is the relatively low error

level shown by the TEST group 24 hr after acquisition. If retention of

recall performance were a function of prior t-trial repetition, one

13
V

might expect a performance error level similar to either the average

error level of all prior t-trials or to the error level of the last ttrial of acquisition. Instead, the error level was similar to that of

the first t-trial of the last acquisition trial cycle (trial 14). It

appears as though TEST group subjects tried to duplicate the recall

performance of acquisition trial 14. If so, this would explain their

relatively low recall error level. To support this notion, other

researchers (Bilodeau, Jones & Levy, 1964) have found that when a series

of t-trials follows a p-trial (as in Cycle 3 of acquisition), subjects

tend to recall their performance on the first t-trial of the series

rather than their performance on either the p-trial or other adjacent ttrials. It is as though t-trial repetition within-cycles produces a

form of serial learning task where subjects try to remember their recall

performance at each successive trial. Because of the strong primacy

effects usually associated with serial motor tasks (Magill & Dowell,

1977), subjects are better able to remember their recall performance on V

the first t-trial of the series and rely on it for later recall.

Additional support for the notion that knowledge of recall performance4

is better for the initial items of a serial task has been reported for

verbal task learning (Klee & Gardiner, 1976; Lockhart, 1975).

A possible answer to the second question of why did TEST group

recall performance improve across retention intervals involves the

notion of retroactive interference. If the assumption is correct that

TEST group subjects did attempt to duplicate their recall performance of

acquisition trial 14, then the decrease in absolute error experienced

between 3 min and 24 hr after acquisition was caused by the dissipation

of retroactive interference. This retroactive interference was generated

initially by added acquisition t-trials performed after trial 14 and was

of sufficient strength to degrade recall performance both at the end of

acquisition and at the 3 min retention interval. However, its strength

apparently dissipated thereafter and did not adversely affect retention

24 hr after acquisition. Although dissipation of retroactive interference

has primarily been found in verbal retention studies (e.g., Postman,

Stack & Fraser, 1968), the general viewpoint that the strength of interitem interference does change over time has received support in recent

motor retention studies (e.g., Wrisberg, 1975).

CONCLUSION

In conclusion, the results of the present experiment clarify certain

training issues regarding the relative effects of presentation and

testing on motor task acquisition and retention. In doing so, they

answer the Army's question of which specific training methods most

effectively promote the highest levels of skill acquisition and retention.

The results indicate that, first, training methods which either

repeat or alternate presentation and testing during acquisition enhance

motor acquisition performance. Final acquisition performance is better,

14

W.L
however, when training is conducted using methods which emphasize either

repeated presentation or alternation of presentation and testing of the

to-be-learned movement rather than its repeated testing.

Second, the primary benefit of repeating testing during training is

enhanced long-term retention. Relative to the other two training methods,

long-term motor retention is improved substantially by a training method

which allows opportunities for repeated testing during acquisition.

Thus, the viewpoint that regards testing as merely an opportunity to

show what has been learned during presentation is incorrect. Apparently,

there are benefits associated with repeated testing which are derived

from the additional memorial information generated by the process of

active recall. Recall serves to modify memory such that prior recall of

memorized motor information facilitates later recall of this same information. This facilitation is greater than that resulting from repeated

study of motor information during presentation.

Third, training methods which manipulate presentation and testing

opportunities during acquisition have a similar effect on the acquisition

and retention of both motor and verbal tasks. This is true, at least,

when presentation and test procedures employed during training are

similar for both types of tasks.

Fourth, the benefits of repeated testing have been 3hown for the

standard laboratory motor task of linear positioning. Future research

should be directed toward answering the question of whether or not these

benefits will generalize to other types of motor tasks. Of particular

interest should be the examination of procedural motor tasks which

require the execution of successive simple motor movements in the correct

serial fashion and are characteristic of many motor tasks performed

within the Army.

Fifth, and lastly, testing should be viewed as an effective way of

enhancing the long-term retention of motor information. This enhanced

retention can be achieved by changing the emphasis of training from

presentation to testing and would occur without the negative aspects of

additional expenditures in training time. money and personnel.

15
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20

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I Chief of NavPer, ATTN: Port-OR

I NAVAIRSTA. Norfolk. ATTN, Safety Ctr

1 Nay Oceanographic, DC. ATTN: Code 6251. Charts & Tech

I Center of Naval Anal, ATTN: Doc Ctr

1 NavAirSysCom. ATTN: AIR-5313C

I Nav BuMed, ArTN: 713

1 NavHelicooterSubSqua 2. FF0 SIF 94601

1 AFHRL PFT) Williams AFB

I AFHRL (TT) Lowry APS

I AFHRL IASI WPAFB. OH

2 AFHRL (DOjZ) Brooks AFB

1 AFHRL IDOJNI Ladlxland AFS

I HOUSAF (INYSOI

I HOUSAF (OPXXA1

I AFVTG iRDI Randolph AFB

3 AMRL iHEI WPAFB. OH

2 AF Inst of Tech. WPAF8, OH. ATTN: ENEiSL

I ATC IXPTDI Randolph AF8

1 USAF AeroMed Lb. Brooks AFB ISUL-4l. ATTN: DOC SEC

1 AFOSR INL). Arlington

1 AF Log Cmd. McClellan AFS. ATTN. ALC.'DPCRB

I Air Force Academy, CO. ATTN- Dept of Bel Scn

5 Nawers & Dev Cth. San Diego

2 Navy Moo Neuropsyctriatric Rich Unit. Sani Diego

1Nav Electronic Lab. San Diego. ATTN: Res Lab

I Nay TrngCen. San Diego, ATrTN Code 9000-Lib

I Navfttlra~ch. Monterey. ATTN: Coo 5bAs

I NaviststGralich. Monitrey. ATTN. Code 2124

I NavrrnqEsuioCtr. Orlando. ATTNI: Tech Lib

I US Dept of Labor. DC. ATTN: Manpower Admin

1 US Dept of Justice. DC. ATTN: Drug Enforce Admin

1 Nat Bur of Standards. DC. ATTN: Computer Info Section

1 Nas Clawing House for MH-linfo. Rockrville

IDenver Federal Ctr. Lakeawood. ATTN BLUM

2 Cefense Documentation Canter

41 Dir PwCrr Army, HO. Russel Ofcs. Canbterry

Scenvtic Adyir. Mil Sd Armv Hn. Russeil Ofcs. Canoerras

4.. ii'o Air Attache, Austrian Emrssv

Cntre rie Rechierche 0e; Facrurs. Huinaine de 'a Defense

'4avor,aie 3russeis

2 Canadian Joint Staff Wasington

I .' Ar Staff Royal Canadian AF ATTN Pers Std Anal 8,

3 Cheof C.anadian Ott Rscn Staff ATTN- C CROSIWI

I1 9r-r.m 0*i Staff B' ttin E~ioasiv Wasngton

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