Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 61
5
Improving Motor Skills
Many strategies can be employed to enhance human motor performance.
The Army has already incorporated into military instruction many proven
psychological techniques, such as demonstration or modeling, feedback,
and reinforcement. The research basis for some of the newer techniques,
however, has not been clearly established, although the sponsors of these
techniques make claims of extraordinary improvements in performance.
Three strategies are discussed in this chapter: mental practice, visual
concentration, and biofeedback. Of the three, mental practice appears to
be the most promising. It has been shown to produce impressive gains
in performance, gains that are even larger when combined with physical
practice. The evidence on visual training exercises is less impressive.
While improving vision in general, the exercises have not been shown to
enhance performance; however, these results are based on a relatively
small research literature, and further investigation may reveal a relation.
A larger research literature exists with regard to biofeedback. While the
promise of enhancement remains, research on biofeedback to date has
largely failed to demonstrate clear effects.
MENTAL PRACTICE
According to Richardson (1967), ''mental practice refers to the symbolic
rehearsal of a physical activity in the absence of any gross muscular
movements" (p. 95~. In real life, mental practice is evident, for example,
when a golfer closes his eyes and in imagination goes through the motions
of putting (Richardson, 1967~. In research studies, to create similar
61
OCR for page 62
62
ENHANCING HUMAN PERFORMANCE
conditions, demonstration of a skill to subjects (or having subjects perform
the skill a few times) is usually followed by asking students to mentally
practice the skill a specified number of times or as many times as possible
within an allotted period. Beyond this, the type of symbolic activity is
largely unspecified. Some subjects may therefore employ visual imagery
of the skill, others may talk their way through the skill, and still others
may use a combination of both strategies. The diffuse nature of this
construct not only makes it difficult to control experimentally, but also
results in the same topics being investigated under a variety of other
names-for example, symbolic rehearsal, imaginary practice, implicit
practice, mental rehearsal, conceptualizing practice, and mental prepa-
ration.
Most experiments on skill acquisition have been variants of a research
design that employs four groups of subjects randomly selected from a
homogeneous population or equated on initial levels of performance.
These groups are (l) mental practice, (2) physical practice, (3) combined
physical and mental practice, and (4) no physical or mental practice
(control). Most studies have compared the performances (before and
after) of subjects who had previous mental practice to a control group
that had not received instructions on mental practice. In the mental
practice group, the subjects rehearse the skill in imagination for a set
amount of time. Subjects in the control group are instructed not to
practice the skill physically or mentally during the interval. A more
appropriate control would require subjects in the no-practice group to
participate in the same number of practice sessions as the mental and
physical practice groups, but with activity that was irrelevant to the task.
In many studies, mental practice and control groups are contrasted to a
physical practice group and a group receiving combined mental and
physical practice. The practice period instituted varies considerably in
the number of trials in each practice session and in the total number and
spacing of trials. In the combined mental and physical practice groups,
practice periods usually involve having subjects either alternate mental
and physical practice trials, mentally practice a number of trials and then
physically practice, or physically practice a number of trials and then
mentally practice. Following this practice period, the subjects' skills were
tested under standard conditions to determine whether their performance
scores differed as a result of the practice condition administered.
PREVIOUS REVIEWS
Several people have reviewed research examining the effects of mental
practice on motor learning and skilled performance on a selective basis.
The reviews by Richardson (1967) and Corbin (1972) included 22 to 56
OCR for page 63
IMPROVING MOTOR SKILLS
63
studies and provided contradictory conclusions. Richardson (1967) re-
viewed studies of three types: (1) those that focused on how mental
practice could facilitate the initial acquisition of a perceptual motor skill,
(2) those that focused on aiding the continued retention of a motor skill,
and (3) those that focused on improving the immediate performance of a
skill. He concluded that in a majority of the studies reviewed, mental
practice facilitated the acquisition of a motor skill. At that time there
were not enough studies to draw any conclusions regarding the effect of
mental practice on retention or immediate performance of a task.
Five years later, Corbin (1972) reviewed many other factors that could
affect mental practice and was much more cautious in his interpretation
of the effects of mental practice on acquisition and retention of skilled
motor behavior. In fact, he maintained that the studies were inconclusive
and that a host of individual, task, and methodological factors used with
mental practice produced different results.
In a 1982 review of `' mental preparation," Weinberg reviewed 27
studies dealing with mental practice. Although Weinberg noted the
. . , ~ . . - . -. . .
equivocal nature of this literature, he maintained that the following
consistencies were apparent: (1) physical practice is better than mental
practice; (2) a minimum skill proficiency is needed in order for mental
practice to be effective; and (3) mental practice combined and alternated
with physical practice is more effective than either physical or mental
practice alone. The latter conclusion is similar to Richardson's (1967)
cautious inference that the combined practice group is as good as or
better than the physical practice trials only.
The most comprehensive review of the mental practice literature to
date is that of Feltz and Landers (19831. This study used meta-analysis
techniques proposed by Glass (19771. (For a review of these techniques
see the paper prepared for the committee by Deborah L. Feltz, Daniel
M. Landers, and Betsy J. Becker, Appendix B.) A search of published
and unpublished literature yielded 60 studies in which mental practice
was contrasted to a simple or placebo control. Collectively, mental
practice effects were examined across SO different tasks, ranging from
dart throwing to maze learning. Analysis of the resulting 146 effect sizes
yielded an overall average effect size for mental practice of 0.48. Except
for the conclusion reached by Corbin (1972), Feltz and Landers's overall
findings supported the conclusions of other reviewers that '`mentally
practicing a motor skill influences performance somewhat better than no
practice at all'' (Feltz and Landers, 1983:251.
Feltz and Landers also examined several variables believed to moderate
the effects of mental practice. Results from these comparisons indicated
that larger effect sizes were found: ~ I ~ in published compared with
unpublished studies; (2) when the posttest was given a longer time after
OCR for page 64
64
ENHANCING HUMAN PERFORMANCE
mental practice rather than immediately after; and (3) in studies employing
cognitive tasks as opposed to motor and strength tasks. Subsequent
polynomial regression analysis revealed that this latter, highly robust
finding was dependent on the time or number of trials subjects were
allowed to mentally practice. Motor tasks having a substantial cognitive
component (i.e., card sorting, pegboard test, maze learning, symbol digit
test) benefited from only a few trials or a few minutes' engagement in
mental practice. By contrast, when tasks that primarily involved strength
or motor components were examined, larger effects were evident only
when subjects mentally practiced for 10 or more minutes or 20 or more
trials. The results also showed no differences in effect sizes for sex, age,
self-paced versus reactive tasks, and type of research design.
Based on their comprehensive review, Feltz and Landers concluded
that ''mental practice effects are primarily associated with cognitive-
symbolic rather than motor elements of the task" and that these effects
"are not just limited to early learning-they are found in early and later
stages of learning and may be task specific" (1983:45-461. This latter
conclusion does not support Weinberg's (1982) conclusion that for mental
practice to be effective individuals must achieve a minimal skill profi
clency.
The most recent review of the mental practice literature is the paper
by Feltz, Landers, and Becker. The majority of the studies (69 percent)
reviewed were the same as in the 1983 review, with 14 additional studies.
They examined: (1) learning effects by means of effect sizes for pretest-
to-posttest differences, (2) mental practice effects compared with no
practice, physical practice, and mental and physical practice, and (3)
effect sizes using more modern meta-analytic procedures recommended
by Hedges and Olkin (1985~. Only studies containing complete data for
pretest and pastiest comparisons were included in the review: as a result,
48 studies for 223 separate samples were reviewed.
The results revealed that the average difference in effect size from
pretest to pastiest across all types of practice treatments was 0.43
standard deviations and that this differed significantly from zero ~ p <
.051. The mean change for all practice conditions was significantly greater
than zero, with physical practice showing the greatest change effects
(0.79), followed by the combined physical and mental practice group
(0.62), and the control group showing the smallest change effects (0.22~.
The average weighted pretest-posttest effect size for mental practice
groups (0.47) was very close to the 0.48 unweighted effect size reported
by Feltz and Landers (1983~. Contrary to what has been previously
theorized in the literature (Corbin, 1972; Weinberg, 1982), combined
mental and physical practice does not appear to be more effective than
either mental or physical practice alone.
OCR for page 65
IMPROVING MOTOR SKILLS
65
When the overall effects were broken down to examine the moderating
variables of task type and type of dependent measure, most of the
variation was found in dependent measures of accuracy and time-on-
target or time-in-balance and in tasks that were essentially motor (versus
cognitive or strength). The failure to find differences for cognitive tasks
as well as for speed, distance, and form-dependent measures was due to
the insufficient number of samples (N ~ 3) having these characteristics.
Although the physical practice group generally had the highest effect
sizes, those of the combined physical and mental practice group were
relatively close. For task measures of time-on-target or time-in-balance,
the combined practice group actually had a larger difference score effect
size than either the physical or mental practice groups. However, this
finding is of questionable significance due to the relatively small number
of samples and a much larger standard error of measurement.
The fact that many of the tasks in the studies reviewed were gross
motor tasks involving accuracy of dart throwing, basketball foul shooting,
ball striking, golf chip shots, bowling, and so on lends greater assurance
that these findings would generalize to tasks of significance to military
performance (e.g., marksmanship). The merging of mental practice with
varying combinations of physical practice may lend itself to military
applications. For some tasks for which actual physical practice may either
be expensive, time-consuming, or physically or mentally fatiguing, the
combined practice may be advantageous, since the effects are nearly as
good as physical practice with only half the number of physical practice
trials. It might be useful in future research to find out whether the gap
between physical and combined physical and mental practice could be
decreased by increasing physical practice relative to mental practice trials
(e.g., a 60:40 or 70:30 ratio of physical to mental practice trials3.
THEORETICAL EXPLANATIONS FOR MENTAL PRACTICE
There are two main theories to explain the effects of mental practice.
The first explanation, termed symbolic learning (Sackett, 1934), posits
that mental practice gives a performer the opportunity to rehearse the
sequence of movements as symbolic components of the task. Most real-
life tasks include components of symbolic (verbalizable) and nonsymbolic
(perceptual-motor) activity. Given an opportunity for mental practice,
covert rehearsal of the symbolic components of the task can occur, and
overt practice can strengthen these activities. Thus, according to this
theory, mental practice facilitates performance only to the extent that
symbolically encoded components are relatively important.
A second type of theory, termed the neuromuscular theory (Jacobson,
1932), posits that it is possible to inhibit peripheral motor activity. This
OCR for page 66
66
ENHANCING HUMAN PERFORMANCE
theory suggests that minimal, or low-gain, neuromuscular efferent patterns
during imagined movement should be identical (in timing and in muscles
used) to those patterns generated during overt movement, but reduced
in magnitude. Although no overt movement takes place, this minute
innervation, as indicated by electromyography (EMG), is presumed to
transfer to the physical practice situation. According to the theory, only
a small, localized efferent from imagery is required for visual and
kinesthetic feedback to the motor cortex and thus for the motor schema
to be further improved (Hale, 1981) or for the corresponding muscle
movement nodes to be primed (Mackay, 1981~. Conceivably, then, mental
practice involves virtually all the neural activity of the overt performance.
There are a number of problems with the neuromuscular theory. The
evidence provided in support of it (see Feltz and Landers, 1983, for a
reviews does not demonstrate that the low-gain EMG activity during
mental practice is similar (i.e., in timing and in muscles used) to the
EMG associated with overt performance of the skill, and it does not
indicate that the presence of low-gain muscle activity during mental
practice is related to subsequent task performance. In essence, investi-
gators testing this theory to date have not measured EMG activity during
overt task performance and have not measured performance following
assessments of EMG activity during mental practice trials (e.g., Harris
and Robinson, 19861.
Furthermore, the idea that mental practice involves "virtually all of
the neural activity" related to the overt performance is called into
question by studies examining regional cerebral blood flow (rCBF) during
overt and covert finger movements (Roland, Larsen, et al., 1980; Roland,
Skinhoj, et al., 19801. With the assumption that rCBF indicates which
part of the brain is being activated, Roland et al. found that, compared
with the rCBF associated with programming and control during the actual
execution of finger movements, mental practice of the same sequence
resulted in some brain regions' not being activated (i.e., primary senso-
rimotor hand area), and the rCBF in the supplementary motor areas
being only 60 percent of the increase observed during actual execution.
Thus, it appears that the programming during mental practice is qualita-
tively and quantitatively different from the programming that takes place
during physical practice.
Perhaps the low-gain muscle activity that is commonly observed during
mental practice may have nothing to do with programming. It may simply
be an artifact associated with "priming'' for the upcoming activity (e.g.,
arousal-attention set, Schmidt, 1982) or-the idiosyncratic tendency through
imagination of movement for some subjects to produce muscular impulses
that correspond to the overtly produced motion (so-called Carpenter
effect, Cratty, 1973~.
OCR for page 67
IMPROVING MOTOR SKILLS
67
Finally, examination of key experiments (Johnson, 1982; Kohl and
Roenker, 1983; Mackay, 1981; Ryan and Simons, 1983) has led reviewers
to conclude that the locus of mental practice effects are cognitive-
symbolic rasher then motor(Annett, 1985; Feltz and Landers, 1983~. As
summarized by Annett (1985:1941:
What seems to be emerging is that the representations which are most effective
in mental practice are of a rather abstract kind, such as spatial context in Johnson~s
experiments, core meaning in Mackay's experiments, and control rules rather
than specific movements in the tracing experiment. If each of these rather different
skills is thought of as being controlled by a motor plan then it would appear that
rehearsal of critical and invariant elements of the plan which may be represented
in imagery is the source of mental practice effects. The executive details of the
plan, which may in any case have to be varied from time to time to meet variable
conditions, probably contribute little and may not be laid down in a permanent
store.
The idea that mental practice effects derive from "rehearsal of critical
and invariant elements of the plan" is not the only cognitive explanation
for mental practice. Other investigators (Tversky and Kahneman, 1973)
suggest an '`availability idea," that is, that well-rehearsed images are
stored in easily retrievable places in the brain. Greater rehears-al would
then allow the image to "spring to mind more quickly" and produce the
belief that the image is more likely to occur as a consequence. This latter
idea is similar to the idea of "images of achievement," which is currently
being promoted as a central concept in a marketed self-improvement
program dealing with the "neuropsychology of achievement." This self-
help program has been singled out for discussion since it is the most
highly developed and influential mental practice program currently being
marketed, and it purports to provide a breakthrough in scientific under-
standing of how and why mental practice and imagery occurs. The general
achievement program as well as videotape programs for a variety of sport
skills are products of SyberVision~ Systems, Inc., Newark, California.
A description and evaluation of the scientific bases for these products
are presented in the next section.
SYBERVISION
On August 29, 1986, two committee members visited SyberVision~
Systems headquarters and interviewed Stephen DeVore, founder and
president, and Karl Pribram, head of Stanford University's Neuropsy-
chology Research Laboratory and director of research for SyberVision~
Systems. The discussion centered on a series of audiotapes called ``The
Neuropsychology of Achievement" (1986) and a set of videotapes (1981)
OCR for page 68
68
ENHANCING HUMAN PERFORMANCE
that concentrates on such sport skills as golf (men's, women's, putting,
and driving), skiing (downhill and cross-country), tennis, bowling, rac-
quetball, and baseball batting. The videotape packages include a 60-
minute videotape of a well-known professional athlete (e.g., Stan Smith,
Al Geiberger, Rod Carew), a personal training guide designed to accelerate
learning, and four companion audiotapes: (1) an explanation of how
SyberVision~ works, (2) teaching tips from the professional athlete, (3)
psychological characteristics of winners, and (4) the musical score from
the videotape for use in imagery recall.
The tapes are of professional quality, showing a performer repeating
the skill over and over. The viewing angle and speed (regular and slow
motion) repeatedly change so as to reduce habituation. Occasionally the
fundamental movement is amplified and simplified through computer
graphics, illustrating the biomechanics of the movement. '~Synchronized
high performance music" is played throughout the tape; the tempo,
rhythm, and timing of the music accentuate the ideal tempo, rhythm, and
timing associated with optimal performance of the skill.
The videotapes are designed for three levels of use: (1) casual,
recreational viewing, (2) biomechanical reinforcement, and (3) neuro-
muscular programming. Of particular relevance is their use in neuromus-
cular programming- a "scientifically formulated" procedure for trans-
ferring the high performance skills modeled on the tape into the nervous
system of the observer. To do this, the instructional manual recommends:
(1) relaxing by using breathing and imagery techniques; (2) watching the
tape while emphasizing a whole-body, lower, upper, then whole-body
focus; (3) upon completion of the tape, turning it off and with eyes closed
imagining each motion about ten times in slow motion or in the comput-
erized graphics mode; and (4) reinforcing the learning by repeated viewing
of the fundamental skill. Following this sequence of steps is supposed to
facilitate the development of "a fluid and graceful rhythm" in synchrony
with the skilled movement on the tape.
The "simple physics of neuromuscular programming'' is presented in
an appendix to the instruction manual, and there is a more complete
description on the first audiotape of ''The Neuropsychology of Achieve-
ment" program, entitled "Your Holographic Brain: The Power of Three-
Dimensional Visualization." According to the audiotape, Karl Pribram
has proposed that the hologram "provides the long sought after model
of how visual sensory information is received, distributed, stored and
recalled by the brain." The tape goes on to say that ''there is enough
lo,
laboratory evidence available to demonstrate physiological, biological
and mathematical bases for the model."
The evidence presented points to similar parallels between the holo-
graphic model and brain function: (1) memory is distributed throughout
OCR for page 69
IMPROVING MOTOR SKILLS
69
the brain in a way similar to a holographic image that is spread over the
entire surface of a film plate; (2) a single holographic plate comes closest
to matching the storage capacity of the human brain (I cubic centimeter
holds 10 billion bytes of information); and (3) both holograms and the
brain can construct three-dimensional images.
According to Pribram's theory of brain functioning, the brain and the
nervous system act as a holographic processor by having an equivalent
object beam (i.e., the eye, since it represents 95 percent of object reality)
and reference beam (i.e., the remaining senses) that interact and create
interference patterns (waveforms) of nerve impulses. These nerve im-
pulses are transformed by the brain into electromagnetic waveforms with
a unique frequency that represents the exact movement specifications.
The decomposition of what is seen and sensorily experienced is accom-
plished mathematically by the brain's ability to perform a Fourier
transform (Instruction Manual, 19811. Once the transformation is com-
pleted, the electrical frequency (timing, rhythm, and tempo) associated
with the movement is distributed and stored throughout the brain. To
recall this stored information, the particular reference beam associated
with the object beam is needed to trigger the stored motion frequency,
''bring it to the surface of memory and neurally reconstruct the stored
memory event" (Instruction Manual, 1981, p. 17~. Thus, activities such
as looking at old photographs may trigger certain emotions that can act
as sensory reference beams to evoke vivid three-dimensional images.
Also included in Pribram~s analysis of imagery are principles derived
from quantum physics and electromagnetic energy. According to the law
of quantum physics, images exist in reality because they are waveforms
that possess energy and matter. Thus, the more one visualizes the image
along with sensory detail and emotion, the greater the electromagnetic
force will be, and the more it will mimic concrete reality.
During the interview, DeVore and Pribram confirmed what a search of
the literature had already revealed: that no research could be found
testing the efficacy of the SyberVision~ tapes. Thus, the sole basis for
the relationship of tapes to performance is anecdotal accounts and personal
testimony of satisfied customers. Although both DeVore and Pribram
wished to encourage research into the use of the tapes for neuromuscular
programming, this type of research was not compatible with Pribram's
research program, and DeVore was not willing to provide much funding
for research.
On the basis of the extensive research literature on mental practice, it
is conceivable that programs like SyberVision~ could improve perform-
ance. However, SyberVision~ is a broad-based package that includes
elements of modeling and imagery, a training guide, tips from professional
athletes, and common psychological characteristics of winners. If per
OCR for page 70
70
ENHANCING HUMAN PERFORMANCE
formance gains were observed, they could not be attributed to mental
practice.
The available research literature on mental practice is consistent enough
to support a recommendation for the Army to conduct evaluation studies
on operational military tasks. However, packages like SyberVision~
should not be evaluated apart from the types of mental practice training
that already have an established research base. They should be evaluated
only within the traditional mental practice paradigm so their pre-post
performance effects can be directly compared with physical, mental,
combined physical and mental, and placebo-control practice conditions.
Research evidence for neuromuscular programming via holograms and
Fourier transforms is elusive. Other than the claims in the SyberVision~
videotapes and audiotapes, no direct scientific evidence was found that
the brain acts like a holographic processor or performs Fourier transforms.
The research to which Pribram referred us (Pribram, Sharafat, and
Beekman, 1984) discusses the possible interpretation of research results
in light of the holographic model, but the data did not provide any direct
support for the model. At the present time, therefore, the cognitive-
symbolic theory still remains the most viable explanation for mental
practice effects.
CONCLUSIONS
The research generally indicates that mental practice accounts for
about half a standard deviation in performance gain over what is observed
for controls. When mental practice is examined for motor tasks having
significant cognitive components or when it is combine,d with physical
practice, the performance gains are much greater. The explanation for
mental practice effects appears to be related to symbolic rehearsal of
critical and invariant elements (i.e., control rules) of the motor plan. The
research does not indicate support for either Jacobson's neuromuscular
theory or Pribram's holographic model as explanations for mental practice.
The overall effectiveness of mental practice supports future research
in at least two directions: one is evaluation studies by the Army on
operational military tasks; the other is research designed to determine
which combinations of mental and physical practice (e.g., 60:40 or 70:30
ratios of physical to mental practice) would best enhance skill acquisition
and maintenance, taking into account time, efficiency, and cost.
VISUAL CONCENTRATION
Many military tasks would be enhanced if concentration were improved.
Although there are numerous experimental techniques to assess concen
OCR for page 71
IMPROVING MOTOR SKILLS
71
tration (e.g., the dual-task paradigm and the probe technique), there are
so far no concentration- and attention-training techniques derived from
experimental research. The training programs designed to develop con-
centration fall into two categories: (1) cognitive-behavioral techniques
(Meichenbaum, 1977) to focus attention better and (2) visual training to
develop the eye muscles.
COGNITIVE-B EHAVIORAL TECHN PIQUES
According to Schmid and Peper (1986), concentration is '`the ability
to focus one's attention on the task and thereby not be disturbed or
affected by irrelevant external or internal stimuli." Within a cognitive-
behavioral framework, Nideffer (1976, 1979, 1981, 1985, 1986) has de-
veloped what he has called attentional control training. The training
consists of cognitive-behavioral techniques such as breathing-muscle
relaxation (to control arousal) and mental rehearsal-positive self-talk (to
shut out negative self-thoughts).
In this literature (Nideffer, 1985, 1986), attention is conceived as
requiring at least two dimensions: width (broad or narrow) and direction
of focus (internal or external). Table 1 illustrates four types of activities
that would be performed best with a given attentional style. The idea is
that, by knowing the types of attentional focus required by the task,
attention can be trained and performance improved (Zaichkowsky, 1984~.
There are two major problems with this approach: (1) research or
evaluation studies comparing the performances of subjects receiving
attentional control training and subjects not receiving training have not
been conducted, and (2) other than for the broad-narrow dimension (Reds
and Bird, 1982), the questionnaire used to distinguish types of attentional
focus (i.e., the Test of Attentional and Interpersonal Style, TAIS) has
poor validity both with respect to factorial validity (Dewey, Brawley,
and Allard, in press; Rubl, 1983; Vallerand, 1983; Van Schoyck and
Grasha, 1981) and construct validity (Aronson, 1981; Jackson, 1980;
TABLE l Activities as a Function of Attentional Style
Width of Direction
Focus Internal External
Broad Used to analyze and plan
Narrow Used to systematically mentally
rehearse a performance situation
or to monitor and/or control
physical arousal
Used to rapidly assess a situation
Used to focus in a nondistractible
way on one or two external cues
OCR for page 91
IMPROVI1VG MOTOR SKILLS
91
Engel, ]985; Perski and Engel, 1980; Perski, Tzankoff, and Engel, 1985).
Furthermore, studies indicate that attention (Perski and Dureman, 1979)
and instructions (Lo and Johnston, 1984) can be ruled out as factors
mediating the HR training effect.
The evidence for HR attenuation during static muscular work, compared
with that during dynamic exercise, is not as consistent. Although subjects
trained to increase HR while encaged in varying levels of muscular work
. · . .. .
~ ~ _
have consistently oeen successful in increasing it above exercise-only
levels (Carroll and McGovern, 1983; Clemens and Shattock, 1979;
Magnusson, 1976; Moses, Clemens, and Brener, 1986), attempts to train
subjects to decrease HR have produced equivocal results. For example,
Clemens and Shattock (1979) found that subjects trained in HR biofeed-
back were also able to decrease HR while engaged in static handgrip
exercise at 10, 30, and 50 percent of maximal isometric contraction.
Moses, Clemens, and Brener (1986) used the same levels of exercise but
did not find that subjects were able to modulate the tachycardia of
exercise. In their study, HR control (particularly decreases) was pro-
gressively impaired as the exercise demands increased.
A point of current debate concerns whether the above-mentioned static
and dynamic exercise findings can be interpreted as evidence for cardio-
specific control. With the exception of the Goldstein, Ross, and Brady
(1977) study, studies examining dynamic exercise have found that blood
pressure does not change; the only apparent training effect appeared to
be specific to the target response (HR) of the training (Fredrikson and
Engel, 19851. Aside from blood pressure, however, the studies examining
ventilation have supported the interpretation that the cardiac changes
imposed on exercise were largely nonspecific, involving parallel changes
in oxygen consumption and respiratory patterns. Moses et al. (1986)
maintain that none of the experiments on static and dynamic exercise
supports '`the inference that individuals may learn to modify the normal
tissue-perfusion functions of the heart" (p. 5191. Instead, in most of the
studies HR has been closely associated with metabolic rate.
RESPIRATION
As pointed out in the previous section, respiratory factors parallel the
HR attenuation that is believed to result from HR feedback during
exercise. Although the major research emphasis has been on cardiac
significance of respiration biofeedback for econ
feedback, the potential
omy of effort in exercise is just beginning to be understood. In fact, it
has been suggested by B.D. Hatfield (personal communication, December
16, 1986) that subjects may be able to modulate respiration more easily
than HR during exercise.
OCR for page 92
92
V)
sol
Cal
Ct
Cal
o
-
.=
in:
o
Cal
-
or
._
·Ct
_`
m
at:
Cal
Cd
Ct
Ct
1
_
~7
Cal:
E
,~ _
TV
Cal ~
._ _
e ct
Ce 3
-
~ O
ILL
hi ~
_
D
3
U)
O
Ct
;^ ."
Ct Cal
A, ~
_ ~
~ D
~ -
._
X
~:5
C)
Cal
X
·- V
£ 3
~5
_ ~
Ct sit
C)
D
O m
_
:=
._ 3 t~ ~
~Ad-- 3
, ~
~ lo,
~ x
. -
~ x
o ~
-
os
~:
.
-
c ~
e ~ s ~ ' ~
`; _ `~,, ~ 3 E
~ ° o ~ ~ ~ C)
V 24 0 :C D ~ ~ ~ ~ ~ C
C ~D ~ D c; ,=> _
_ _ _ _ _ _ _
C)
C) .>
D S ~ ~ ~C O
_ _
_
_
oo
_
_
_
~0
O
V)
. -
-
oo
-
-
-
o~
Ct
C
Ct
_~
x
-
o
-
C
~C
o
C
Ct
~i
OCR for page 93
93
._
C~
s~
x
y: D
a
C)
cr.
. _
-
x
-
r3
-
V,~
-C)
~L
:r :~:
~4
C ~
._ ._
3
-
D
V
C
z
~ C;: ~
_ Ct ·- C
~ ~ O
Y ~ e ~ 0
L~
-
G
-
o
5
Ct
CJ ~
- o
V)
~ _
._ _
_ ~
- C)<
:~ ~
~ ~ _
5~ 3
0.1) LL O
~ :1: '=
C)
3, .'
'"G., -
C) C; X
,= s~ C}
Ct
~ =
o ._
04 ~
C =;
._ ~
=: ~
- _
3
u::
o
tV ·-
3 ~
o
C ~ y ce D
C ~V C _ ~
e ~ c,, ~ 3 e _
D LL ~ D ~ D
U)
O
~: t~ ~,~ o~
- -O ~C4 ~ ~
~ ~ ~ ' O
(~] ~ ~ ·_ ~ O
-
V)
C
O
~ ._
_ ~
3 ~
_
cn
~ -
o
_ CC
~ a y a ~ a y.~, a a ¢ ,~, ~ a
ct D ct D ~ 5 t ~eD ct D i~
~C
~, C ~ ~
'~ ~ O ~ ~
. C ~ _ ._ G) - 00
O - ~ ~ o ~ L} ~ O O
_ O ~OG
-
O _ ~
cr ~0
_ oo X - C
_ _ ~
_ - ~C
Ct
~ - tV . ~`~ -
~ ~ ~3
OCR for page 94
94
ENHA NC1NG H UMA N PERFORMA NCE
The efficacy of respiration feedback was recently investigated by
Hatfield et al. (19861. In this study, 12 aerobically trained athletes were
provided with ventilatory feedback on a digital display updated every 15
seconds. With regard to the HR biofeedback studies, the exercise was
of greater intensity (i.e., just below calculated ventilatory threshold). A
within-subjects design was employed, with subjects receiving, in random
order, three conditions (feedback, control, and distraction) during a 36-
minute rum The distraction condition consisted of a coincident (antici-
pation) timing task with timing feedback given every 3 to 4 seconds.
During the control condition, subjects were instructed not to attend to
feedback of any kind.
The results revealed that the metabolic cost of the run was undiffer-
entiated across conditions. However, minute volume and ventilatory
equivalent were significantly reduced with feedback compared with the
control and distraction, which were not differentiated. Similar results
were found for pressure of end tidal 0' and CO' inhaled by producing
relatively more CO' with each expiration.
Although this is only a single study, the results are consistent with the
running economy results found for HR feedback. Taken together, these
results demonstrate that feedback procedures can alter metabolic effi-
ciency during intensive activity in trained athletes. These results are
particularly impressive considering the near maximal intensity of the
work performed. Considering the magnitude of the effects at high levels
of exercise intensity, it would be useful in future research to compare
HR and respiratory feedback in modulating a number of physiological
and biochemical parameters associated with exercise.
THERMAL SELF-REGULATION
Although many clinicians have found thermal training useful as an aid
in treating migraine headaches, frostbite or frostnip, and Raynaud~s and
other vasoconstrictive disorders, thermal self-regulation with biofeedback
may have other cold-weather applications as well (Kappes and Mills,
1985; Taub, 19771. For instance, it is known that extrinsic warming of
the hands improves manual efficiency and reduces pain in conditions of
extreme cold stress (Lockhart, 19681. In order to perform effectively in
cold environments, it is necessary to preserve surface finger temperature
to prevent a loss of both tactile sensitivity and dexterity. With obvious
implications for the military, Kitching, Bentley, and Page (1942) have
examined the usefulness of insulation in increasing hand temperature.
Unfortunately, such attempts have often been counterproductive for
performance, since heavy insulation often obstructs movement and
decreases hand efficiency. Thus, it would be advantageous if hand warming
OCR for page 95
IMPROVING MOTOR SKILLS
95
in operational environments could be achieved by other means. One
alternative that has gained attention recently is the use of biofeedback to
increase hand temperature.
Research on the self-regulation of hand temperature in cold environ-
ments (see Table 5) has shown, with few exceptions, that feedback
training of digital skin temperature can slow a loss of peripheral skin
C7 , , ~ '= ~ ~ t 1 ^^ ~
temperature. In the three studies examining performance tHayOuK, lYbU,
1982: Kanoes. Chanman, and Sullivan, 1986), the ability to maintain hand
temperature resulted in increased performance. For example, Hayduk
(1980) was able to train six subjects to increase skin temperature by
7 ~ rem ~ '
5.64°F, and this increase was found to be related to decreased pain as
well as improved performance on measures of manual and finger dexterity,
hand strength, and tactile sensitivity. A one-year follow-up (Hayduk,
1982) confirmed that these same subjects maintained their learned ability
to self-regulate hand temperature. Unfortunately, the interpretation of
feedback effects in the Hayduk studies is confounded by training consisting
of both classical conditioning and biofeedback components. However,
other researchers have achieved the same temperature (Kappes and
Chapman, 1984; Kappes, Chapman, and Sullivan, 1986) and performance
(Kappes, Chapman, and Sullivan, 1986) results as Hayduk, even when
training had been restricted to biofeedback practice accompanied by a
relaxation audiotape.
With the exception of the Donald and Hovland (1981) study, the studies
listed in Table 5 trained and tested subjects' thermoregulatory abilities
inside controlled temperature chambers with total body exposure. Training
of this type has led to much better transfer of temperature self-regulation
to cold environments than studies that have trained subjects in warm
environments with only their hands exposed to cold stress (Donald and
Hovland, 1981; Simkins and Funk, 1979; Stoffer, Jensen, and Nessett,
19771. Comparisons of indoor and outdoor environments have shown
that skin temperatures of subjects trained outdoors increased, while
~ A_ +~ AI ~ ~_c~ -~31~ ~1~7 maintain their ~.mneratures when
tested in an outdoor environment (Kappes and Chapman, 19841. By
contrast, the temperatures of the control subjects continued to go down
in the cold environment. Although the results of this study suggest a
.
~UOI~ t1 Wilily lilUQ~1 ~ ~V~1~ Allay IlA~AA4~^ ~44~ __-
thermal specificity of the training environment, subsequent work has
failed to confirm this finding (Kappes, Chapman, and Sullivan, 19861.
It has yet to be determined if the impressive performance gains achieved
with hand warming can generalize beyond the resting state. Future
research needs to determine if self-regulation of hand temperatures can
be of operational use in situations in which subjects are more physically
active, have greater cognitive load, or are exposed to additional forms
of stress (i.e., competition, combat, and so on). It would also appear that
IT
OCR for page 96
96
C)
so
Blob
so
G
V)
o
. _
Ct
s::
Cd
U.
so
-
La
o
it:
o
-
C)
i.
V,
4-
-
Cal
on
it:
._
._
Ct
so
EM
m
_'
Ct
C)
Lo
-
Ct
it;
V,
U.
-
-
w
~ ~ °
Cal W W
U) ~
00
0£
O
Ct - '
so e.
Ct
Ct
O W W
° ° E-.
~ > ~
~ I ~
o
Ct
00
_
~ W
w
04 -
C: ~
He
W
Ct _
W -
id Ct
-
w
U)
Cal
w
a
W ~
_ ._
Ct ~
~._
00
·^ Ct ~
~ W
_ ~ cn
W ~ W
_ ._
5 ~ CC
u ~e~ -0
w
e 3 1I E 0, ~ .= ~ ~ II A ~ 3 ~
~ :, E ~ ~ ~ ~ ~ ~ ~ ~, ' ~ E
c)
.-
_ ~
E~ ' ~
W ~ .
W ') +
_
. ~
. _ W
_
._
W
~ _
x o
w ~
+
~o
o W
oo =:
o
-
-
-w ~o 0
·~'
~Q
Ct
Ct o
~o ::
o
oo
_
_
Ct
_
o
· ^
+
~ ._ o
s~ ~ ~,L4 ~
G o o
C) Ct + +
Ct ~
-
~ cr~
C: _
. _ _
Ct _
oo
ct cr
`: _
o -
OCR for page 97
97
3
_ s~
0 0.1)-
_ ,= C': _
~ E
E ~ ~ x
C ~~
C~ ~,
(= OC
E
1 ~
o ~o
^ a:> ~L~ ~ ~ LL,^ ~
[,L. ^ ~L O O
~L O O O o L, ~`,L, 00 [L t~
o ° ~ ° ° o I ~ + ,~ ~ + o
+ O ~ ~ o
~, ~ ~ - ' ~ V ~ ~ ~ C ° ' ~
° ~ oc ~i 3 ·_ o o o ~ ~ o 4' x ~ o
.m ~ ~ ~ =, c =, o ~ ct ~ O ~ E ~
_ ~ ~
e E ~ · D ~ o ~ Cc ~
X ~ + ~ 3 ~ ~ + ~ + X oo + +
_
~C
oo
Q 00
cr.
Ct _
=: _
_ ~_
_ ~
_cea~
t
30) oo~
:~-Q
Ct~ ~
~4~
OCR for page 98
98
ENHANCING [IUMAN PERFORMANCE
biofeedback research on performance in cold environments (mountain-
eering and skiing, as well as operational tasks important to the military)
should examine subjects' accuracy in recognizing hand temperature. The
protocols used in the studies in Table 5 did not call for subjects to be
trained in the specific skill of temperature estimation; instead, they were
trained to increase temperatures by relaxing. Thus, when asked to estimate
their peripheral skin temperature, subjects were uniformly inaccurate
(Kappes and Chapman, 19841. Perhaps discrimination could be improved
by having subjects, as part of the training protocol, report subjective
changes in skin temperature.
MULTIPLE AUTONOMIC RESPONSES
There are a few examples in the research literature of biofeedback for
which more than one autonomic response has been given. One study
examined the combined effects of feedback and open-focus attention
training (a cognitive relaxation procedure) on economy of effort in bicycle
ergometer work (Powers, 19804. The four subjects in this study were
given 20 sessions of EMG and temperature feedback-open-focus attention
training following baseline sessions to determine oxygen consumption,
heart rate, and systolic blood pressure. To demonstrate acquisition of
skill, subjects had to reduce mean EMG levels as well as finger and toe
temperature to preestablished criteria.
The Powers results indicated that all but one subject had significantly
improved efficiency of pedaling the bicycle ergometer. For all subjects,
the percentage reductions from pretest to posttest were as follows: heart
rate 8.35 percent: oxvaen consumption, 11.75 percent; and systolic blood
, ,.._, ~ · - - r _A ~ ~ _, _~ =_
pressure, 9.35 percent. Although the magnitude of these findings is
impressive, the failure to employ a placebo control group and the
confounding of biofeedback with open-focus training limits a strictly
biofeedback interpretation for the findings. Despite these limitations,
Powers suggested that the mechanism for the biofeedback self-regulation
process
. . . may be an organization by means of attentional cortical open focusing leading
to bilateral brain hemisphere synchrony; this, in turn, promotes trophotropic
processes of the limbic and midbrain area, normalizing the regulatory centers of
the hypothalmus, autonomic nervous system, and reticular activating system.
( 1980:3928-B)
According to Powers, the end result is a state of homeostasis that
facilitates optimal functioning.
In an interesting series of studies by Cowings and associates (sowings,
1977; Cowings, Billingham, and Toscano, 1977; Cowings and Toscano,
OCR for page 99
IMPRO VINC MOTOR SKILLS
99
1977, 1982), a training method involving biofeedback, autogenic therapy
(Schultz and Luthe, 1969), and distraction from symptoms was employed
to deal with problems associated with the onset of motion sickness.
Cowings ( 1977) found that, compared with either biofeedback or autogenic
therapy alone, the combination produced larger magnitude, less variable
response changes that were more stable over time. The 12-day training
method, called "autogenic feedback training'' (AFT), also accounts for
individual response stereotypy (Lacey et al., 1963) by often presenting
up to four simultaneous sources of autonomic feedback (heart rate,
respiration rate, blood-volume pulse, galvanic skin response, or intercostal
muscle activity). The subjects could choose the feedback (auditory or
visual) for the given autonomic variable most relevant to their own
autonomic response to the motion sickness experienced before testing.
The AFT method is believed to deal directly with the final common path
of autonomic manifestations of motion sickness, and thus it should work
equally well when the underlying mechanisms are different (e.g., Coriolis
acceleration affecting the semicircular canals and linear acceleration
affecting the otolith organs).
To create nausegenic stimulation by means of Coriolis acceleration,
Cowings employed a rotating chair (6 to 30 revolutions per minute)
combined with 45° head movements. Experimental subjects given AFT
training were able to withstand the stress of Coriolis acceleration signif-
icantly longer than control subjects (sowings, Billingham, and Toscano,
19771. The findings were the same whether subjects were initially found
to be moderately or highly susceptible to Coriolis acceleration (sowings
and Toscano, 19824. Symptoms of motion sickness were alleviated for
subjects given AFT training only when compared with subjects performing
a distracting task (Black Jack task) or no task at all (Toscano and Cowings,
1982~. In this latter study, five of the six subjects undergoing AFT training
either significantly reduced or totally suppressed symptoms.
A recent study by Dobie et al. ( 1986) showed that a treatment combining
biofeedback (EMG and temperature) and cognitive-behavioral therapy
(confidence building and desensitization) was effective in increasing
tolerance to stimulation-eliciting motion sickness. However, when the
separate effects due to biofeedback versus cognitive-behavior therapy
were examined, only the cognitive-behavior group increased tolerance to
stimulation and reported less symptomatology than the biofeedback and
control groups. This could suggest that biofeedback may have little to
do with Cowings's findings. However, Dobie et al. (1986) interpreted
their findings as perhaps due to (1) the minimal stimulation experienced
in their study; (2) not basing feedback on the unique type of autonomic
distress experienced by subjects during pretest acceleration tests; and (3)
not exposing the feedback and control groups to similar adaptive exposures
OCR for page 100
100
ENHANCING HUMAN PERFORMANCE
of visually induced motion' as given to the combined and cognitive-
behavior groups. Considering these '
is difficult to conclude much from the Dobie et al. Innings. tt may oe
that biofeedback is only efficacious if the symptoms are severe or if the
relevant autonomic response system is known and then specifically trained
in each individual.
CONCLUSIONS
. . . ..
· · · . - ~
design ano procedural varlallo~lv' lr
Two major problems appear repeatedly throughout the research on
biofeedback and performance. One problem' which limits any clear
interpretation of biofeedback effects, is the use of biofeedback as part of
broader therapeutic techniques, for example, biofeedback plus classical
conditioning (Hayduk, 1980, 1982) or autogenic therapy (sowings, Bil-
lingham, and Toscano, 19771. The other problem, primarily evident in
studies examining training in EMG, EEG (alpha or theta), and HR while
subjects are performing tasks, is that no prior knowledge is available
concerning what the most desirable levels of EMG, EEG, or HR should
be to produce optimal performance on the tasks of interest. In other
words, the training criteria were not based on EMG, EEG, or HR levels
known to be important for effective task performance.
In the areas in which biofeedback has shown more consistent perform-
ance benefits, the relations between, for example, ERP and various
thresholds, slow wave potentials and readiness to respond to various
tasks, HR or respiration and running economy, and hand warmth and
finger dexterity, have been established by previous research. Thus, the
direction and magnitude of the physiological parameter to be trained
could be more clearly established. Provided subjects could be trained on
the particular physiological measure, a performance enhancement was
generally found. Until more is learned about the most effective EMG,
EEG (alpha or theta), and HR levels for the execution of particular tasks,
biofeedback research in these areas should not be pursued.
Although the biofeedback research on event-related and slow wave
potentials, HR slowing during exercise, and hand warming has been more
consistently related to performance enhancement, specific problems must
be addressed before these techniques can be implemented into military
training programs. For instance, more research needs to be conducted
an th`~ mart e.ffi~.io~ training programs for producing a greater per-
centage of subjects who can be trained. In addition, the generality of the
laboratory-generated relations needs to be tested in operational environ-
ments important to the military. It needs to be determined if the fairly
robust effects found in the laboratory can extend to performance of more
complex tasks having greater cognitive load or while physically active
~ ~ & % ~ ~ _ · ~ ~ ~ v ~O 1 ~
OCR for page 101
IMPROVING MOTOR SKILLS
101
subjects are exposed to additional forms of stress (e.g., competition or
combat). Further research is also needed to train subjects to determine
when BEG, HR, and temperature levels are inappropriate for task
performance so the self-regulation process can be initiated.
Finally, the performance effects of biofeedback need to be compared
with other performance-enhancing techniques (e.g., autogenic training,
relaxation, imagery, knowledge of performance or results). In reviews
comparing biofeedback with relaxation training, Silver and Blanchard
(1978) concluded that there was no consistent advantage of one form of
treatment over the other across all of the psychophysiological disorders
examined. Even though certain types of biofeedback have been shown
to improve performance, biofeedback has not been shown to work better
than some other, less costly techniques. In addition to determining what
technique is most efficacious and cost-effective, future research also
should consider what technique is most efficient (works faster), durable
(beneficial effects hold up longer), generalizable (benefits a larger pro-
portion of people), and convenient (easier to administer and easier to
perform) (Silver and Blanchard, 1978~.
SOURCES OF lNFORMATlON
Our conclusions are based on several sources of information that were
made available to the subcommittee. The literature on mental practice
was reviewed according to meta-analysis procedures in the Feltz, Landers,
and Becker paper prepared for the committee. In addition, the subcom-
mittee received briefings from practitioners involved in the development
of visual training exercises. Useful information was also conveyed by
product developers during site visits. These visits enabled subcommittee
members to better understand how training programs are developed from
certain assumptions about psychological processes, some of which may
have a basis in the research literature.
Representative terms from entire chapter:
slow wave
