Research Note 86-39

TOWARD A BETTER UNDERSTANDING OF THE ACQUISITION OF SKILL:

In THEORETICAL AND PRACTICAL CONTRIBUTIONS OF THE TASK APPROACH

Richard A. Schmidt

Motor Control Laboratory, Department of Kinesiology

University of California, Los Angeles

Contracting Officer's Representative

Judith Orasanu DTIC

SELECT"- I

DEC 2 4 Defl

BASIC RESEARCH D

Milton S. Katz, Director

U.S. Army

7Z- Research Institute for the Behavioral and Social Sciences

P= April 1986

Approved for public release; distribution unlimited.

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TOWARD A BETTER UNDERSTANDING OF THE ACQUISITION Interim Report .

OF SKILL: THEORETICAL AND PRACTICAL CONTRIBUTIONS Tanuarv-Februarv 86

OF THE TASK APPROACH 6. PERFORMING ORG. REPORT NUMBER

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IS. SUPPLEMENTARY NOTES Contracting Officer's Representative, Judith Orasanu.

Schmidt, R. A. (1986). Toward a better understanding of the acauisition of %

skill: Theoretical and practical contributions of the task approach. Paper

presented at the symposium entitled "Future Directions in Exercise/Sport

Research", Arizona State University.

19. KEY WORDS (Continue on reverse aide If neceeary and Identify by block number)

task-oriented motivation knowledge of results

process oriented complex and simple tasks

motor skills acquisition contextual interference

practice feedback

20. ABSTRACT (Cmi "f'e o iweee f necessar ar idenify by block number)

"During the 1970's and 1980's, the field of motor learning generally abandoned

the so-called task-oriented tradition, in which the effect of various experimental conditions on task performance or learning were evaluated. It by a

process-oriented viewpoint, in which the dominant focus was the understanding

of various underlying processes or mechanisms in performance and learning. ., .

Such a shift has resulted in many changes, such as a focus on relatively simple

tasks where the underlying processes could be more easily identified, manipulated, and understood; and, it emphasized the concern for (cont.)

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very fundamental research questions. it is argued here that this shift

has not been particularly healthy for motor learning, because the tasks

that were used have had questionable external validity, and the theories

that were developed and evaluated were not maximally suited to the under- ...

4standing of the phenomena of prcieand learning, w research programs d

noted deal with the effects of conditions of practice and feedback! -

knowledge of results, both of which offer a return to the task orientation. \I

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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

WM. DARRYL HENDERSON

EDGAR M. JOHNSON COL, IN

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Research accomplished under contract for

the Department of the Army

Motor Control Laboratory, Department of Kinesiology

University of California, Los Angeles

Technical review by

Steve Kronheim

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SUMMARY OF:

TOWARD A BETTER UNDERSTANDING OF THE ACQUISITION OF SKILL:

THEORETICAL AND PRACTICAL CONTRIBUTIONS OF THE TASK APOROACH

Richard A. Schmidt

Motor Control Laboratory

Department of Kinesiology

UCLA

During the 1970s and 1980s, the field of motor learning generally

abandoned the so-called task-oriented tradition, in which the effect of

various experimental conditions on task performance or learning were

evaluated. It was replaced by a process-oriented viewpoint, in which the

dominant focus was the understanding of various underlying processes or

mechanisms in performance and learning. Such a shift has resulted in many

changes, such as a focus on relatively simple tasks where the underlying

processes could be more easily identified, manipulated, and understood; and,

it'emphasized the concern for very fundamental research questions. I argue

here that this shift has not been particularly healthy for motor learning,

because the tasks that were used have had questionable external validity,

and the theories that were developed and evaluated were not maximally

suited to the understanding of the phenomena of practice and learning.

I have argued that a return to a task orientation will be important in

carrying us forward in the next few decades. As support, I discuss two

research programs which have used this tradition recently--one dealing

with the effects of conditions of practice stemming from the work of Shea

and Morgan (1979; Lee & Magill, 1983), and another dealing with feedback

and knowledge of results emerging from Lavery's research (Lavery, 1962; .........

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Schmidt & Shapiro, 1985). In this work, the focus is on the conditions of

practice which maximize learning of simple or complex motor tasks. The

focus is solidly theoretical, and has already provided considerable

theoretical thinking and empirical work examining the nature of these

phenomena. But at the same time, these examples show much more external

validity to real-world situations. Both ask about procedures that are

actually used by people charged with the intelligent design of learning

environments (the scheduling of practice and feedback). And, many of these

examples could be easily conducted with more complex, realistic movement

behaviors, with modern measurement capabilities being involved. Or they

could even be conducted in practical settings themselves, perhaps in

collaborative efforts with scientists in teacher behavior or movement

education. As such, these two research situations provide interesting

models for future efforts where theoretical and practical research goals

can be achieved simultaneously. A return to the discarded task approach can

provide many important contributions, and may even serve as the paradigm

of the future in the motor learning area.

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Understanding the acquisition of skill has been the focus of formal

scientific interest for nearly a century, with a considerable increase in

these activities in the 1960s. As beginning scientists at about this time,

we were tremendously enthusiastic about the future of motor learning and

its many relatives. Of course, for physical education one goal had always

been the teaching of skills, and a vigorous approach to the scientific study

of the motor learning seemed only natural. But more broadly, we were

convinced that the acquisition of skill was a central concern for human

functioning in general, being relevant to such diverse applications as job

training and accident prevention in industry, artistic performance in music

and dance, man-machine interactions in equipment and vehicle design, and

the relearing of lost skill capabilities after traumatic injury or stroke. We

believed that we could we could bring rigorous scientific procedures to bear

on this largely under-studied area, and have a major impact both on

theoretical understanding and on practical application. Now, some 20 years

later, I find it interesting to consider what we have accomplished, what

forces have acted to direct our thinking and research, and what we should do

next in the study of these important general problems.

Motor Skills Acquisition--Qne View of Diur Current Status

One of the major forces acting on researchers in motor behavior in the

1970s came from the idea, popularized by Pew (1970), that a so-called

"task-oriented" approach to motor behavior was not going to be sufficient

for the future. At about this time in psychology, there was a shift toward a

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new cognitive tradition (Neisser, 1967), in which many underlying cognitive

processes, stages, and mechanisms were being proposed and studied to

account for observed behavior. This trend was paralleled by the call for

process-oriented theories and research methods in movement behavior, in

which analogous motor processes would be the focus of study rather than

the overt movement behaviors of the earlier task-oriented tradition. This

had a nice "ring" to it, as it seemed to allow researchers in movement

behavior to develop and test theories concerned with the fundamental

processes behind movement control and learning. And this style seemed to

carry with it much more status-which was (unfortunately) quite important

at the time--following as it did the current thinking in cognitive science.

Process- an Ta-Oriented Aporoaches

The paradigms associtated with the older task-oriented approach tended

to focus on the performance of usually rather global tasks such as the

pursuit rotor, the Mashburn task, and the like, and asked about the effect of

nearly countless variables that affected the nature of practice (e.g., massed

vs. distributed practice, the nature of feedback, the effect of fatigue, etc.).

These tasks were usually quite complex, involving many perceptual and

motor processes simultaneously, and it was usually not possible to

attribute performance changes to variations in a particular process (e.g.,

response programming). Also, while these tasks involved rather elaborate

movement control, the measurement systems were usually quite gross, with

a single score (time on target) summarizing perhaps 30 s of behavior.

Increased use f timl as. This new tradition demanded a change to

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simpler tasks. We began to see many more studies using reaction-time to

study the processes in motor programming, linear-positioning tasks to

evaluate whether movements were based on displacement or distance cues,

and ballistic-timing tasks to evaluate the role of error-detection processes.

These tasks were well suited to the investigation of some questions, but

were disappointing to those who wanted to understand how complex

movement behaviors in everyday life were controlled and learned. The tasks

involved performances that, for the most part, the. learners could already

perform (e.g., linear positioning); what was apprently learned in the

laboratory was the "fine tuning" associated with making the particular

already-learned action conform to the requirements of the experimental

situation. Almost never were new coc-dinations learned, such as would be

involved in learning a complex gymnastics stunt, and the movements were

usually governed by a single degree of freedom. And, largely because of

this, there seemed to be a systematic shift away from relevance to

real-world motor behaviors. This shift is obvious when one examines the

kinds of motor tasks that we were willing to label as "motor behavior."

Small amounts of practice. The study of learning gradually declined in

popularity during this period, although there were exceptions. When

learning LAM studied, it was usually done with these simple tasks, in which

the improvements seemed to be extremely rapid; many learning experiments

were done where the practice phase was a few dozen trials, and seldom did

practice periods exceed 100 trials. The use of relatively small amounts of

practice seemed to further remove us from relevance to real-world

problems, as it was difficult to argue convincingly that the 50 trials or so

of a linear positioning task were in some way informative about the
4

analogous processes leading to high-level skill in sport, industry, or music.

Simole tas and motivation. These simple tasks had other problems as

well. In our own research with various simple timing tasks, the learners

tell us that the actions are overly simple. When lengthy practice is

provided, the subjects often become quickly and visibly bored. With

questionable subject motivation, we wonder whether we are meeting the

basic assumptions for the meaningful study of learning. And, these

difficulties meant that the problems of small levels of practice could not be

,o met simply by increasing the amount of practice. What seems to be needed

is more "interesting" tasks for the learners, which would sustain motivation

through relatively advanced levels of practice, allowing the effects of

, various independent variables to be examined there.

Asumptions of the Process-Oriented View

But the criticism that the process-orientation led to tasks which were

overly simple, and paradigms which were not particularly relevant to

real-world behaviors, is perhaps too strong. Behind this research tradition

are various assumptions which, if correct, would seem to argue that this

approach will be most effective for understanding motor learning.

Principles f comolex an simple ia ". One assumption is that the

principles of movement learning will be the same for simple and complex

motor tasks. That is, the effect of a particular independent variable (e.g.,

the nature of information feedback) will not interact with task complexity.

If this assumption is correct, then it makes sense to study tasks which are

simple, because measurement, control, and manipulation are far easier here [,.

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5

than in tasks which are more complex. But, if this assumption is incorrect,

it is possible that the principles of learning derived from the study of

simple tasks will be largely irrelevant to real-world situations involving

more complex movement behaviors. We need solid evidence about the

viability of this assumption, as seldom have the same variables been

examined in the same way for simple and complex movements.

The l of practice. A second assumption (also present in the task

approach) is that the principles of learning will be similar for various

levels of practice. That is, the effect of some independent variable will not

interact with the level of practice of the learners. Thus, we are often

tempted to talk about various "laws" of motor learning which are generated

from tasks with very low levels of practice, thus assuming (or at least not C%

seriously questioning) whether these principles will also apply for higher

levels of practice so often seen in real-world situations. If this assumption

correct, much effort can be saved by examining simple tasks under

relatively low levels of piactice. But if, as many suspect, this assumption

is not correct, then the low levels of practice that are typically used will

have poor applicability to many real-world situations.

Technology has also played a role in these shifts, as response

complexity usually implied measurement difficulties. Such problems were

faced in the older task-oriented tradition by measurement of only the global

response outcome (e.g., time-on-target for a 30-s trial), and ignoring the

patterns of limb movement behavior completely. When the shift was made

to the process-oriented approach, patterns of limb movement behavior were

also ignored, but here by making the task so simple that the pattern of

movement behavior was nearly trivial. Now, however, with the arrival of

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6

affordable laboratory computer methods for the recording of various simple

dimensions of limb movement (e.g., the position-time record of a hand-held

lever), measurement problems in more complex behaviors can be examined in

a time-efficient manner, and do not provide justification for avoiding

complex movement behaviors in our research.

Conseauences of the Process Orientation

My own view is that, while this tradition has had a number of strong

points and interesting findings, on the whole is has not been healthy. When I

speak with my colleagues in other subfields of kinesiology, the sport

sciences, or physical education, nearly all seem to agree that understanding

the phenomena involved in the acquisiton of skill is of central importance.

But most politely hasten to add that our current field of motor learning does

not address these questions very well. What, for example, can our field

really tell, in some empirically based and non-intuitive way, about the

teaching of Olympic athletes, the improvement of methodology in teaching,

or the procedures used to train skilled workers in industry? Very little, I

think (although there are a few bright spots which I will address in a later

section). And, many university programs in physical education--even those

focusing on the preparation of teachers--are increasingly discovering that

they can do very well without courses in motor learning. Administrators

apparently believe, with good justification, that coursework in motor

*- learning is simply not relevant to the problems involved in teaching.

I want to be clear that I am not simply calling for an applied focus.

Some (e.g., Adams, 1972; Schmidt, 1982) argue that an applied focus too

. . . . * - . . . J 4 -- - . . . - ... * -. . * .
7

strongly emphasized can impede progress in a field because it prevents the

establishment of more fundamental principles which lead to theory. The

development of effective theory can, after some years of waiting for its

refinement and testing, become enormously effective for guiding decisions

about many practical matters. In this vein, Kerlinger (1973, p. 10) argued

that "There is nothing more practical than a good theory." When these

fundamental problems have been worked out, application to teaching

situations (by us or someone else) should be relatively easy.

But the theories we developed and tested in the past decade or so have

not been very satisfactory in meeting this objective. Many were too global

(e.g., schema theory) to be an effective source of guidance for particular

situations. These views have contributed to our overall insights about

motor learning, but there is not enough that is concrete on which to base

intelligent changes in practical circumstances. But perhaps more serious is

the fact that most of these theories were studied with the simplistic tasks

that seemed to be demanded by the process-oriented approach. Thus, even if

the theories seemed to account relatively well for the data in such

" situations, the question is raised about the relevance of these tasks--and

the theory that explains them--to any important real-world situation.

In many ways, this argument is parallel to that used by the ecological

psychologists, who argue, for example, that the many investigations of

"visual information processing" with tachistoscopic displays and suddenly

presented stimuli were fine for telling us about thes situations, but

produced results and principles which may be largely irrelevant to

understanding how an animal uses visual information to orient itself in the

world (e.g., Turvey, 1977). In this sense, the process-oriented tradition for

-- .. - . N- .- %
8

motor behavior has led us to become extremely non-ecological in our

research. We design tasks which are perhaps well suited for uncovering or

manipulating a certain hypothetical process, but at the same time these

activities may take us systematically farther from the understanding of

1"real" movement behaviors because they are so contrived, stripped of

intrinsic feedback, or otherwise made artificial1 . As Rosenbaum (1985) has

said, the brain (and motor system, it must be added) can do many wonderful

things; but it can also perform many silly things that we ask of it in the

laboratory. One must wonder if the principles of learning the silly things

discovered in the laboratory are going to tell us about "normal" movement

behavior phenomena which motivated most of us in the first place.

Overall, my most critical view is that the field of motor learning has,

with considerable success during the past decade or so, worked extremely

vigorously and systematically--through the development of theoretical

thinking, new experimental paradigms, and simple motor tasks--to become

as esoteric and as irrelevant as it can be to the solutions of real-world

problems. Part of the problem is based on status, where it became much

more acceptable to study abstract problems of motor processes--with

highly contrived and simple motor responses--than it was to examine

problems which were more nearly representative of many real-world

situations. Certain paradigms and tasks seemed to be used mainly becasue

they were "in fashion." And, part of the problem has been a relative lack of

N interesting problems to examine with the procedures associated with the

older task-oriented approach, with the newer issues about underlying motor

processes apparently being genuinely more interestng to some.

This last point leads to the second major section of this paper. After a

I-,
9

decade or so of work associated with the process-oriented apporach, a

number of new ideas, methods, and empirical findings have surfaced which

appear to provide justification for returning to the older task-oriented

approach. And, these problems appear to have considerable potential for

study in tasks with somewhat more complexity, and the principles that are

emerging appear to be reasonably applicable to many real-world settings

involving motor learning. Rather than, as one might assume, these benefits

coming at the expense of theory development, many interesting theoretical

ideas are being formed and tested in these situations, which should lead to a

much better understanding of motor-learning processes in general.

Future Directions: Som Examples n Suggestions

The examples of these new directions for research in movement learning

are numerous, but two major lines of work serve to illustrate this kind of

direction very well. One of these directions involves some new thinking on

various conditions of practice, and the other concerns the effects of various

manipulations of feedback about goal achievement.

Research on the Conditions of Practice

Considerably after most of the field of motor behavior had either

abandoned the study of learning, or had shifted to process-oriented studies

of motor behavior, Shea and Morgan (1979) published a study which resides

squarely in the task-oriented tradition. Their theoretical orientation

stemmed from the late William Battig, who was interested in the idea that

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various aspects of a practice situation which initially cause "difficulty" for

the subjects (keeping slightly different versions of the tasks separate), and

which make performance in practice poor, seem to provide greater learning

of the task(s) when they are later evaluated on a retention test (e.g., Battig,

1966, 1979). This "intra-task interference," also called "contextual

interference," had been studied to some extent in verbal tasks, but it had not

really been generally recognized as an important factor for learning.

Shea and Morgan used a number of different versions of a relatively

simple movement task, in which the learner had to begin with the hand on a

"home" key, and then move to knock over three small barriers in a prescribed

order before returning to the "home" position again; the task was to

minimize movement time. Three different task versions involved placing

the barriers in different positions, so that the movement directions and

distances between them were different in the different tasks. Subjects

practiced these three tasks in an acquisition session of 54 trials, where the

order of practice was varied between groups. In one condition, practice was

Blocked, in that 18 trials of Version A were completed, then 18 trials of

Version B, and 18 trials of Version C. In the Random condition, the same

number of trials of A, B, and C were completed, but the order was

randomized, with no single version being present on two consecutive trials.

Eiure I abu1t here.

In Figure 1 (left) are the movement times for these two groups on the

initial practice trials. The Blocked condition produced much more effective

performance than the Random condition, with steeper improvements and

faster movements at the end of practice. In Battig's terms, the mixing of

the different versions of the tasks in the Random condition produced some

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11

sort of contextual interference, making the performance of each of the

versions of the tasks less effective than if the learners had an opportunity

to work on each of the versions separately.

But the interesting finding occurs on the retention tests. The

procedures generated essentially two separate experiments, where the

effect of Blocked or Random practice in the acquisition phase was evaluated

on (a) the Blocked retention tests or on (b) the Random retention tests, with

retention tests either 10 min or 10 days after acquisition. These results

are shown in the right portion of Figure 1. Consider first the Random

retention tests, shown as the circles. Here the group with Random practice

in acquisition (open circles) was far faster than the group with Blocked

practice in acquistion (filled circles). Notice also that the Blocked-Random

group performs better than the Random-Random condition in the acquisition

phase, but that this order is reversed in the retention phase. It could be

argued that the Blocked group in acquistion had to shift conditions to the

Random retention test, whereas the Random group did not, and that this

shift per se was in some way disrupting for the subjects.

However, this concern is reduced if we examine the Blocked retention

tests, seen as the squares in Figure 1. Here, the Random-Blocked condition

(filled squares) was faster than the Blocked-Blocked condition (open

squares), and Random practice in acquisition was again more effective for

long-term retention than Blocked, even though it was now the Random

subjects who were were required to shift conditions for the retention test.

In general, subjects who practiced under Random conditions in the

acquisition phase were more effective on the long-term retention tests,

regardless of the conditions under which they were tested (Blocked or

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Random), but the effect was much larger for subjects tested on the Random

retention test.

These long-term retention tests, aside from providing evidence about

the effectiveness of the conditions of practice in acquisition, have an

important status of their own. In most real-world learning situations, we

engage in practice to acquire the capability for responding that is to be

demonstrated in the future. The dancer practices long hours during the week

not so much because of effective performance in practice per se, but rather

so that she can perform effectively in the concert next month. So this line

of research on contextual interference tells us that, for maximization of the

goal of effective long-term retention, excellent performance in the practice

session per se is not necessarily the answer. It also suggests that we

understand practice far less well than we are inclined to believe.

Theories 2f contextual interference. These effects, due in some way to

the context in which a particular version of the task is practiced in

acquisition, have been the subject of an interesting theoretical debate.

Shea and Morgan (1979; Shea & Zimny, 1983) have argued that the effect is

due to Random practice causing the subjects to process information about

the various versions more "deeply" and completely, leading to increased

distinctiveness between the tasks, more elaborate associations being

formed for the various versions, and hence better long-term retention. Shea

and Zimny, using post-practice interview techniques, found that the

subjects reported many more descriptions of the tasks which used

extra-experimental associations (statements similar to "That pattern

looked like a Z") and intra-experimental distinctions ("This figure was like

that one"), which tend to support their views about the deeper and more
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elaborative processing as a basis for the better retention.

On the other hand, Lee and Magill (1983; Magill, 1983) have argued that

the effects are caused by forgetting the solution to the movement

problem--the way in which it was programmed or the particular strategy

used, analogous to the views presented by Cuddy and Jacoby (1982). Here,

the presentation of a different version (e.g., B) of the task causes the

subject to forget the "solution" to the movement problem that was just

generated on the previous trial (with Version A, for example), which then

requires the learner to generate the solution for A again when it is next

required. Subjects under Blocked conditions do not have to regenerate the

solution on the next trial, because it is very similar to that just used on the

previous trial. In this view, the generation of solutions to the movement

problem is an important factor in learning, and conditions which prevent or

minimize this generation process (e.g., Blocked practice) will be poor for

learning and long-term retention as a result. These issues have generated

considerable interest and attention, and a number of additional experiments.

Implications for future research directions. In addition to the

interesting debate about the source(s) of these counterintuitive learning

effects, implications for the problems raised in the first part of this paper

are provided. First of all, the paradigms involve what most would classify

as a task-oriented approach, in which the effects of some conditions of

practice in the acquisition phase are evaluated on measures of learning (or

retention). Second, such an approach is strongly theoretically motivated,

with the conditions of practice being designed specifically to test various

hypotheses about the nature of the learning effects (e.g., Lee & Magill,

1983). Thus, this style of work is not, as some have claimed about the

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14

task-oriented approach in general, just empirically motivated, in which

experimenters search without a theoretical direction for those conditions

of practice which happen to be most effective for learning. The search

identified here is a principled one, done for solid, fundamental reasons.

These aspects also contribute a great deal to other goals of motor

learning research discussed earlier. For example, although Shea and

Morgan's (1979) research uses relatively simple and artificial motor tasks,

the tasks are, by almost any criterion, considerably more complex than

those used in the process-oriented approach. And, even more complex tasks

could have been used, with elaborate measures of the subjects' movement

patterns perhaps being included. The result is that such work has

considerably more relevance to many real-world situations.

But this feature has an additional, related aspect dealing with the

applicability to teaching situations. The variable manipulated here--the

nature of practice sequences--is one of critical importance for real-world

teaching activities in physical education, music, and industry, where

practice on various tasks has to be scheduled intelligently by instructors

who wish to maximize learning efficiency. Not only can the findings that

come from these laboratory experiments be reasonably safely generalized to

real-world settings, they suggest experiments in naturalistic settings

themselves. This latter aspect is particularly interesting for me, as I can

imagine a new approach to the science of instruction (integrated with those

concerned with teacher-learner interactions) based on paradigms of this

general kind, and where the payoff is a theoretically oriented, empirically

based, yet applicable study of practice phenomena. Viewed in these terms,

the task-oriented approach appears to have much to contribute.

=SS...
15

Feedback and Knweg of -Results

A second general research area relevant to the present problem deals

with what most workers in the field consider a critcally important variable

for learning--the information feedback received after attempting a

movement. This feedback is usually called knowledge of results (KR), and is

defined as verbal (or verbalizable) information, over and above that usually

received in the task via other sensory channels, that evaluates the

movement in terms of its environmental goal. Early work has shown that, if

the task is structured so that the learners cannot obtain information about

the consequences of the actions by themselves, then essentially M learning

is achieved from practice unless KR is provided to inform about errors

(Bilodeau, Bilodeau, & Schumsky, 1959; Trowbridge & Cason, 1932; see

Salmoni, Schmidt, & Walter, 1984, for a review). Such findings have led

researhers in the area to believe that KR is the single most important

variable for learning, except possibly for practice itself (Bilodeau, 1966).

Methodological concerns with KfR research. But our review of these

issues (Salmoni et al., 1984) has led us to question some of these strong

interpretations for KR and learning. Most of the studies examining the

.- experimental manipulations of KR have conclusions based on the

performances measured during the time that the KR variable is being

manipulated. The difficulty is that one cannot be sure with this procedure

whether (a) the experimental manipulation of KR has affected some

relatively permanent acquired capability for responding (i.e., it has

influneced l ), or (b) whether it has simply influenced performance

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16

temporarily, in which case the beneficial effects of the KR manipulation

would disappear when it is removed. There is ample reason to suspect that

KR may have temporary performance effects, such as the well-known

"energizing" (motivating) effects of KR, its guidance properties which tell

the performer what do do next, and so on. The result is that what we

thought were the principles of KR for learning may simply be principles of

KR for temporary performance.

One solution to this problem is to examine performance on a retention

test in which the KR has been removed. When this is done, the temporary

effects of the KR manipulations are largely removed, leaving behind the

relatively permanent effects which are the "products" of the learning

process. A few, largely ignored, studies in the KR literature have used this

procedure. When it is used, the effects of the KR manipulations (measured

on the retention test) are often quite different from those seen in the

acquisition phase. These results are often quite counterintuitive,

suggesting major revisions about the principles of KR and learning.

Summary KR. Lavery (1962) examined a method of giving feedback

termed "Summary KR," in which the experimenter drew a graph of the

subject's performances over each of a series of trials, but the subject was

only allowed to see this graph after 20 trials were completed. Other

subjects received KR in the usual way (termed Immediate KR), while yet

another group had both Immediate and Summary KR (Both). The

performances of these three groups over 6 days of practice are shown in the

left portion of Figure 2. The groups with immdeiate KR (Immeidate and

Both) were far more effective in performance than the Summary group,

which performed relatively more poorly and improved at a slower rate.

'p=. ° . . . ° . . . o . . . o , o . , . . . . . . .. . . . . . .
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17

Thus, because the Summary KR condition was very poor for performance,

these and other findings have forced the view that Summary KR (and the

so-called "trials delay" technique which resembles it) were devastating for

learning (Bilodeau, 1956,1966).

Eig=2 abut b=r.

However, notice the performance differences when the KR is removed on

a retention test (Days 7-10, 37, and 93). Here, the performance of the group

with Summary KR in the acquisition phase is approximately the same as it

was in acquisition, indicating very strong long-term retention; but the

performances of the Immediate and Both conditions show large losses on

Day 7, and continuing on subsequent days. If learning is measured, as I have

suggested, via the performance on a no-KR retention test, then we are

forced to the conclusion that Summary KR was the most effective practice

method for learning. This is a very nonintuitive finding, because it suggests

that the most effective conditions for performance during practice

(Immeidate and Both) are the least effective for learning. Furthermore, it

was not the case that the Summary KR condition improved learning, because

the Both condition also had the summary information, and it performed most

like the Immediate condition in acquisition and retention phases. Rather,

the conclusion seems to be that immediate KR in some was interferes with

learning of the task, perehaps by causing the subject to be guided by it too

heavily in the practice phase, as I suggested earlier (Schmidt, 1982).

Figure .aut hre.

* Following Lavery's lead, my colleagues and I at UCLA have been

investigating these and other similar phenomena. In one study, we (Schmidt

& Shapiro, 1985) searched for an optimum number of trials for the summary

• 4. = P • " - " - " . " " . " . " . " . " " " . " ' . " . " . " . - . . - - . -
18

report. With a relatively simple timing task, we used summaries of 0 (i.e.,

immediate KR), 5, 10, and 15 trials, with these KR reports spread over 100

practice trials. Our results are shown in Figure 3, for immediate (10 min)

and delayed (2 days) retention tests without KR. At 10 min, there was

essentially no effect of the various feedback treatments manipulated in the

acquisition phase. But by 2 days later, the errors were ordered inversely

with the length of the summaries, with the 15-trial summary condition

showing essentially no loss over 2 days, and the 0-trial summary condition

showing considerable decrement. Again, this is a very curious finding,

because the groups with the most effective performance during acquisition

(here, the 0-trial summary condition) were the poorest in terms of learning,

measured on a long-term retention test. All of these results suggest that

we do not understand the processes of feedback utilization very well.

Implications for future research directions. These results on

manipulations of KR, like those on context effects discussed in the previous

section, share strong common implications for future of research

directions. First, these findings are strongly empirically oriented, in that

they are concerned with the fundamental relationships between the

variations of KR and the subsequent learning and retention. The

establishment of such empirical laws are absolutely essential for a field

that claims to understand the processes in motor learning. But, these

findings are also strongly theoretically oriented, in that they ask about how

KR "works" to produce learning. Various theoretical ideas (such as the

guidance hypothesis mentioned above) are possible to explain these effects,

and considerable effort is being directed at understanding these phenomena.

But what impresses me most about these results is their potential

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19

applicability. These experiments manipulate variables (the schedule of

delivery of information about response errors) which are under the direct

control of teachers in real-world settings. It seems a relatively small jump

from these laboratory manipulations to applications where summary KR

procedures could be used. This kind of work seems to suggest studies

actually conducted in natural settings, perhaps revealing instances where

these variables would be most effective for maximizing learning, or I- uncovering limitations to generalizability. And finally, these results on KR

utilization--like the context-effects research discussed above--represent

an older task-oriented approach to motor learning, where various conditions

of practice are manipulated to determine the effects on task learning. This

suggests an important use for this old paradigm in the future.

The Task .pl roach: paradirn gf ±g Future?

In asking about what kinds of empirical and theoretical directions we as

a field of motor learning should take as we approach the end of this Century,

I have tried to assess the contributions of the various approaches which

have been predominant (at least in my brief tenure) in relation to the kind of

problems that we are to address as a field. Many see our field (as I do) as

the study of the acquisition of motor skills, with a major emphasis on the

(empirical) principles of learning, on how these principles lead to theories

about the underlying processes of learning, but at the same time with

considerable focus on where these fundamental principles might be applied

in real-world learning situations. If so, then the process-oriented approach

so prevalent in the past decade does not suit my purposes very well, because

W41,
20

it has lacked two important features: (a) it seems to lack generality to

real-world situations becasue of the emphasis on simple motor behaviors,

and (b) it focuses on classes of fundamental problems which do not have

obvious external validity. This situation is not neccesarily related only to

the task-orientation, but perhaps also to our underdeveloped thinking about

fundamental principles of learning. But for whatever the reasons, I have

argued here that, primarily because of the focus we have adopted during the

1970s, we have made ourselves largely irrelevant to the understanding of

what most of us would agree are "interesting" motor skills.

I believe that one solution is to re-adopt the task oriented approach to

the study of motor learning. In a discussion of these ideas with my

long-time "colleague" and good friend George Stelmach, he asked

essentially, "How can you really justify taking such a large step backward

to a tradition we all rejected years ago?" My response, which is the theme

of this paper, is based on a number of factors. First, if our field has to do

with the establishment of empirical relationships between conditions of

practice and learning, then it is clear that we have a long way to go before

that goal is realized. Many interesting and important phenomena have never

been studied seriously. And new findings, such as the KR and

contextual-interference effects described here, suggest that we do not

understand very much about the nature of such fundamental things as

feedback and practice. The task approach is beautifully suited to the

examination of such questions.

Second, the process approach has taken us away from situations which

have much potential for practical application. Simple tasks and the focus on

rather esoteric, overly simple theoretical ideas have not, in cold retrospect,
) 

21

proven to be very useful either as explanations of motor learning, or as

guidance for application. Perhaps it is too early to be so critical, as

theories take considerable time to be developed and tested effectively. But

the examples I have provided here suggest that use of the task orientation

*. may be a more direct and effective way to understand problems relevant to

our field. The problems here deal with effects of conditions of practice, an

area of central interest to motor learning. The methods might (or might

not) use more complex tasks which provide important increases in external

validity. The ideas are strongly theoretical, and have led to many

interesting explanations of practice phenomena and to experiments designed

to test them.

Many of these problems could actually be conducted in real-world

situations, sacrificing nothing with respect to experimental rigor (provided

that the measurement system for the tasks is adequate), while gaining a

great deal in terms of generality.' Along these lines, I think it is time for

an increased collaboration between motor learning and the new field known

as "teacher behavior," whose primary concern is teacher-learner

interactions in classroom stiuations, where often groups of learners with

realistic tasks are involved. The new findings I have mentioned here, and

" numerous others, could form an attractive model for collaborative work

between these two areas, as the findings have strong revelance to, and could

be actually be replicated and extended in, classroom settings.

For some, my recommendation to "regress" to an earlier, and supposedly

discarded, research tradition will seem strange and perhaps unworkable.

But such an approach seems reasonable in light of my admittedly personal

biases about the nature of the practical and theoretical goals of our field.

dP

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22

The research examples mentioned here, in which interesting theoretical n

practical issues are studied simultaneously in the same experimental

paradigm, represent excellent models for the nature of future work in this

area, and seem to provide considerable justification for at least considering

the task orientation as the paradigm of the future.

I

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23

Footnotes

1. But, to be fair, Zelaznik (1985) has pointed out that many of our

real-world situations are pretty silly and non-ecological too, such as doing

giant swings on the horizontal bar or flying a helicopter. It is just that

these particular activities have, for various reasons, become popular and

accepted as skills, where linear-positioning tasks and the like have not.

And, perhaps because they are often nonecological and contrived, many

accepted skills are "difficult" to perform, which makes them interesting as

sports (pole vaulting), or important to study for societal reasons (e.g.,

helicopter safety).

-N.

.°"
24

References

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American Psychologist, 2Z, 615-622.

Battig, W.F. (1966). Facilitation and interference. In E.A. Bilodeau (Ed.),

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Battig, W.F. (1979). The flexibility of human memory. In L.S. Cermak & F.I.M.

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Bilodeau, I.M. (1956). Accuracy of a simple positioning response with

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Bilodeau, I.M. (1966). Information feedback. In E.A. Bilodeau (Ed.),

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Bilodeau, E.A., Bilodeau, I.M., & Schumsky, D.A. (1959). Some effects of

introducing and withdrawing knowledge of results early and late in

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Kerlinger, F.N. (1973). Foundation behavioral esearch (2nd ed.). New York:

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Lavery, J.J. (1962). Retention of simple motor skills as a function of type of

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Lee, T.D., & Magill, R.A. (1983). The locus of contextual interference in

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Magill, R.A. (1983). Insights into memory and control in motor behavior

through the study of context effects: A discussion of Mathews et al. and
25

Shea and Zimny. In R.A. Magill (Ed.), Memory and control.of action.

Amsterdam: North-Holland.

Neisser, U. (1967). Cognitive pychology. New York: Appleton-Century-Crofts.

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Rosenbuam, D.A. (1985). Presentation at a conference entitled "Attention,

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Universitat Bielefeld, West Germany.

*Salmoni, A.W., Schmidt, R.A., & Walter, C.B. (1984). Knowledge of results and

motor learning: A review and critical reapparisal. Psychological

Beulletin, 95, 355-386.

Schmidt, R.A. (1982). Motor control and learning: A behavioral emohasis.

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* Schmidt, R.A., & Shapiro, D.C. (1985). Summary knowedge of results and

motor learning. Manuscript in preparation, UCLA.

Shea, J.B., & Morgan, R.L. (1979). Contextual interference effects on the

acquisition, retention, and transfer of a motor skill. Journal of

Experimental Psychology: Human Learning and Memory, 5, 179-187.

Shea, J.B., & Zimny, S.T. (1983). Context effects in memory and learning

movement information. In R.A. Magill (Ed.), Memory and control of

action. Amsterdam: North-Holland.

Stelmach, G.E. (1984). Personal communication.

Trowbridge, M.H., & Cason, H. (1932). An experimenal study of Thorndike's

theory of learning. Journal of General Psycholoay, 7, 245-260.

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Hillsdale, NJ: Erlbaum.

pI
26

Zelaznik, H.N. (1985). Personal communication.

9

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27

FigreCaptions

Figure 1. Mean movement time for a simple motor task acquisition and

retention phases for Random and Blocked conditions of practice (from

Shea & Morgan, 1979).

Figure 2. Mean percent correct responses in a simple movement task under

three conditions of knowledge of results during an acquisition phase

when KR is present, and during a retention phase where KR was

withdrawn (from Lavery, 1962).

Figure 3. Mean absolute constant error for a simple timing task in immediate

(10 min) and delayed (2 days) retention tests without KR as a function

of the summary KR conditions in acquisition (from Schmidt & Shapiro,

1985).

9.'

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FIGURE 1 28

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FIGURE 2 29

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FIGURE 3 30

.44

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