Imagery orientation and vividness: their effect on a motor skill performance.

Pie, Joan S. ; Tenenbaum, Gershon ; Bar-Eli, Michael 等

Two studies were conducted to examine the effect of imagery on a eye-hand coordination task (throwing a ball in a basket). In the first study 75 high school students were divided into 3 treatment conditions and one control. The experimental conditions were comprised of watching a short video clip of either 15 successful basketball foul shots or 15 unsuccessful shots, or of recreational skiing. Then the subjects were taught how to experience and feel movement through relaxation and imagery. In the second study, similar procedures were applied to 20 subjects who were students in a coaching academy. In study 1, the four shooting trials were performed at one week intervals; in study 2, they were performed twice a week. In study 1, results indicated that while imagery vividness remained high and unchanged across four trials in all groups, performance improved with time as a result of acquaintance with the task. However, in study 2, external imagery orientation increased while performance remained unchanged. We conclude that imagery can contribute to performance only when subjects efficiently master the task. Accordingly, novice subjects should first practice the task and only later integrate imagery into their practical programs.

The use of imagery along with physical practice has been found to enhance performance more than the use of physical practice without imagery (Smith, 1987; Weinberg, 1982). One recent explanation as to why physical practice accompanied by mental practice enhances performance, can be sought through the bioinformational theory (Hecker & Kaczor, 1988; Lang, 1977, 1979). This theory enlightens the relationship between the athlete's experience level and the physical and psychological responses to imagery scripts (Hecker & Kaczor, 1988). Because the athlete has experience with the skills being described during the imagery training, he/she can then experience the mental practice both psychologically (mentally creating the situation's sounds, feelings, etc.) and physically (the feelings of arousal-anxiety, the muscle movements, the heart rate, etc.). These responses enable the athlete to further practice the skills needed for their sport, while being relieved from the constant exertion of physically performing (Hecker & Kaczor, 1988). However, thus far, more research is needed to demonstrate the dominance of the bioinformational approach over the other theories in this domain (Suinn, 1993).

Imagery, observed through self-report, can vary in its vividness. Vividness is described as being the clarity, color, and realness of the situation imaged (Smith, 1987). Some studies have suggested that the more vivid the image, the better the outcome of the performance (Start & Richardson, 1964). However, Smith (1987) pointed out that it is unknown whether the elite athlete actually uses imagery (before, during, and/or after the execution of an action) and if so, whether the vividness of the images can affect that and/or other performances. Thus, how performance is affected by these components of imagery is still not completely understood.

Mental imagery can be classified into two basic cognitive approaches: internal and external. Internal imagery is where the performer visualizes the skill as if he/she were actually performing; in contrast, external imagery is where the performer visualizes him/herself as if watching from an outside perspective (i.e., watching him/herself perform on television) (Hall, Rogers, & Barr, 1990). Past research has found that more experienced athletes have a tendency to use internal imagery more often than external imagery (Hall, et al., 1990; Mahoney & Avener, 1977). This tendency is in line with the bioinformational theory, in that internal imagery produces kinesthetic feelings of the movements being imagined (Jacobson, 1932; Mumford & Hall, 1985). Since the experienced athlete is more familiar with these movements, he/she can therefore use internal imagery more efficiently to produce the feelings and improve the execution of skilled movements (Hecker & Kaczor, 1988).

Indeed, more experienced athletes (elite level) have been found to utilize internal imagery more frequently than less experienced athletes ("weekend" type athletes), who tend to use external imagery more frequently (Epstein, 1980; Smith, 1983). In addition, motor tasks seem to be more receptive to internal imagery than to external imagery; in contrast, non-motor tasks tend to be more receptive to external imagery than to internal imagery (Smith, 1987; Suinn, 1993). In general, Epstein (1980) has suggested that the combination of both internal and external imagery is the most effective way of improving performance.

It is unclear whether a person is imaging in the exact manner that he/she is told (Sheehan, 1967). Disagreement is also found in the literature as to the amount of time required for imagery to be effective on performance. Feltz and Landers' (1983) and Smith's (1987) reviews indicate that more time and trials are needed for each imagery session when imaging a motor task than when imaging a cognitive task. It has been suggested that there is an optimal amount of time (yet to be confirmed) for imagery, just as there is an optimal amount of time for physical practice to be most effective for the improvement of a skill in a sport (Twinning, 1949). Mental practice or imagery should also take into account the nature of the task and the characteristic of the individual, with the assumption that imagery should be conducted the same amount of time that it takes to actually perform the task (Weinberg, 1982).

The present study investigated the effects of imagery orientations on a motor skill performance. The imagery procedure used here was an adapted version of the visual motor behavioral rehearsal (VMBR) originally suggested by Suinn (1976). It was hypothesized that if the content of an image is controlled through first watching a model of what is to be imaged and then through instructed Imagery sessions, the viewing of the model and imagining of that performance is expected to cause the subject to produce an enhanced performance. This hypothesis was investigated in two contradictory situations. In the first situation the subject viewed a successful performance (i.e., a basketball free throw shot that is successfully completed), and then transferred that image of success to his/her imagery practice sessions (imaging him/herself successfully completing a basketball free throw shot). The second situation consisted of a subject viewing an unsuccessful situation (i.e., a basketball free throw shot that is unsuccessfully completed), and then transferring that image of failure to the imagery practice sessions (imaging him/herself performing an unsuccessful basketball free throw shot).

The idea to introduce an unsuccessful image was based on the psychotherapeutic literature, which suggests that it is possible to extinguish maladaptive behaviors that have been reinforced unknowingly by others (related to this study, it could be described as "being afraid of missing a foul shot in front of an audience as it happens even to the most elite players"). Karoly and Kanfer (1982) introduced the technique of implosive therapy to describe the extinguishing of maladaptive behaviors. Implosive therapy is a technique that relies on the principle of extinction as it focuses on extinguishing the conditioned avoidance of the anxiety-arousal stimuli (for this study, the successful and unsuccessful images). In implosion therapy, the clients are asked to imagine and relive aversive scenes associated with their source of negative arousal. However, instead of trying to diminish arousal from the treatment sessions, the therapist deliberately attempts to elicit a massive "implosion" of negative arousal or anxiety. With repeated exposure in a "safe" setting, the stimulus loses its power to elicit arousal and the destructive avoidance behavior is extinguished.

Woolfolk, Murphy, and Parrish (1983; cited by Suinn, 1993) used unsuccessful imagery with college students who were divided into groups according to their golf-putting ability and assigned to one of three conditions: correct practice imagery, incorrect practice Imagery, and no training (control). The "correct" condition had subjects correctly practice putting the ball into a cup; in the "incorrect" condition, subjects imaged the ball just missing the cup. This study found significant differences between the conditions, with the "correct" practice imagery condition subjects improving by 30.4% from their baseline measurements, the "incorrect" practice imagery condition subjects deteriorating by 21.1% from their baseline measurements, and the control condition subjects improving by 9.9% from their baseline measurements. However, no published study is known in sport psychology to test unsuccessful imagery based on implosion theory (Suinn, 1993).

Another aspect of imagery is related to the question of whether images do become stronger (more vivid) over time in regular Imagery practice sessions. It was assumed that just as learning a new skill or task, one can also learn to improve his/her imagery skills as well as to produce more vivid images, and increase the use of internal imagery (Smith, 1987). Therefore, subjects in the present investigation, who gained more experience with imagery (whether positive or negative), were expected not only to improve their performance of the motor skill on top of the "normal" learning effect being experienced with practice, but also to increase their frequency of the use of Internal imagery as well as the vividness of their images.

Method

Study One

Subjects. Four Israeli high school physical education classes (n=75, age 16.34 + 0.49 years; males and 31 females) took part in Study 1. All students were from the same high school located in Tel Aviv. All were from moderate to high socioeconomic status families. They were randomly assigned to one of the following conditions: a successful free throw treatment (n=20) viewing and imaging a successful basketball free throw and performing the task (n=20); an unsuccessful free throw treatment (n=19) - viewing and imaging an unsuccessful basketball free throw and performing the task; a ski treatment (n=18) - viewing and imaging a skiing model then performing the task; and a control group (n=18). Groups were balanced in terms of gender, roughly each group had equal number of males and females.

Instrumentation and Apparatus

Three 30 minute video cassettes containing a total of eight minutes of the following were used: (1) General information as to what the students were about to see and do (two minutes): "Hello and welcome. You will be participating in the following project, which will include watching a short video of a sport; then you will be guided through an imagery session, where you will be performing the sport seen in the video." (2) A short video (the model) of either 15 successful basketball foul-shots, or 15 unsuccessful basketball foul-shots, or recreational skiing (each video is two minutes in length; only one model was used per video). The ski video was used as a neutral model to control for the possibility of the influence of performing imagery as such, unrelated to its content. The basketball models included well known athletes playing on the current championship team of the Israeli professional basketball league. The ski model was of professional non-Israeli skiers in a recreational setting; this model was considered neutral because in Israel, participating in the sport of skiing is quite rare to near distant. (3) Visual motor behavioral rehearsal specific to each sport situation viewed in the video model (four minutes in length; two minutes relaxation, two minutes imagery rehearsal).

Suinn (1976) introduced VMBR as a type of mental practice that allows a person to experience imagery as if it were reality, with feelings of physiological, emotional, and neuromuscular involvement. VMBR is made up of two steps: (a) relaxation; (b) imagery rehearsal. This type of mental practice is easily replicated in practice and research settings because it does not demand special training or skills and the descriptions used to create the images are very descriptive. In conjunction with the type of model viewed and imagery rehearsal practice, the amount of time it takes to complete a basketball foul shot should be the optimal amount of time needed for the imagery sessions.

In the present study, an adapted version of VMBR was used with multiple imagery practice sessions, as recommended by Feltz and Landers (1983) to produce an effect on the performance task. According to Smith (1987), because of task specificity motor skills such as basketball free throws should be imaged for five or less minutes. Therefore, the mental practice sessions in the present study were two minutes in length. Instructions for the unsuccessful basketball foul-shot were as follows (in Hebrew): "Imagine yourself standing at the foul line, exactly as you saw in the video. Now shoot the ball to the basket. Watch it hit the rim of the basket and miss. Watch the ball fall to the ground. Feel the disappointment of missing the basket."

Three free throw shooting positions were marked on the basketball court's key: (a) the actual free throw line, (b) a mark to the left of the free throw line, and (c) a mark to the right of the free throw line. Each position was 19 feet from the basket line, which is the same distance used on regulation sized courts.

Issac, Marks, and Russell's (1986) Vividness of Movement Imagery Questionnaire (VMIQ) was administered to the subjects. This questionnaire is used in sport settings and is a valid measure of imagery vividness. The VMIQ measures both external and internal imagery. Two different versions were used in the study, each one pertaining to the model/imagery used in the video seen. One questionnaire was used for those subjects viewing the successful/unsuccessful basketball foul-shot models, and the other was for those viewing the ski model. The subjects who viewed the successful and unsuccessful basketball free throw videos were asked how vividly they could imagine the basketball, their wrists, legs, the basket, and their body as they released the ball to the basket. The subjects rated their legs, hands, head, wrists, and their whole body as they were skiing down the slopes. The subjects rated their imagery vividness on a Likert type scale with ratings from one (no image at all) to five (image perfectly clear and as vivid as normal vision).

Each questionnaire was broken down into three sections, i.e. items pertaining only to (a) body parts, (b) movement of body parts, and (c) movement of the whole body. For each of these three parts, the subject was asked to imagine first from an internal perspective (imagining him/herself and his/her own body move) and then from an external perspective (imagining someone else's body and movement). Each part was measured separately and the averages were recorded. The mean vividness score was calculated by dividing the vividness score of all items by the number of items.

Procedure

Each of the four groups performed the imagery and practice sessions once a week for five consecutive weeks. In the first week, a baseline measurement of 15 basketball free throws was calculated from three positions marked on the basketball court. Each subject attempted five free throws from each of the positions (free throw line, to the left of the free throw line, and to the right of the free throw line). The subjects were to randomly shoot one basket at a time at each of the three positions until all 15 throws were completed. In the first week, students were randomly assigned to the various baskets on the court, and returned each week to the same basket with the same group of students. One student at each basket was asked to record the throws with a "+" for those baskets made and a "-" for those throws missed for each student at that basket. Only the total number of baskets made (+) were recorded.

The second through the fifth weeks consisted of the following procedures for the three experimental groups: The students were seated in a classroom with a video cassette recorder and a television watching and participating with the eight minute group-specific video (described before). Then these students were given the respective imagery questionnaire to complete. After completing the questionnaire, the students went to a gymnasium, where the basketball courts were located, and completed the same performance task conducted during the baseline measurement.

The control group underwent the following procedure during the second week: The students arrived at the gymnasium/basketball courts, and were asked to answer the following question: "Do you use imagery when attempting a basketball free throw?" ("Yes" or "No"). Attached to this question was the same questionnaire that the successful and unsuccessful basketball free throw imagery groups responded to. If the student answered "yes" to the first question, they were told to continue responding to the questionnaire. If the student answered "no" to the first question, they were told to stop and not to respond to the remainder of the questionnaire. Then, the students completed the same performance task as the other three groups, in line with the baseline measurement. For the control group, weeks two to five consisted of only arriving to the gymnasium and completing the performance task (the same task as during the baseline measurement and the second week).

While Study 1 looked at imagery orientation, vividness, and performance among high school students for six weeks, Study 2 was conducted with college aged students, who had more experience with this particular skill. In Study 2, adapted VMBR procedure and performance sessions were conducted on a more condensed basis, that is, two times a week for two weeks.

Study Two

Subjects. Students from the National Israeli School of Coaches took part in Study 2 (n=20; 14 males and 6 females). Students were randomly assigned to one of the four treatments as described in Study 1. The mean age of the students was 23.77 + 2.69 years and they came from medium socioeconomic status.

Procedure. Instrumentation and apparatus were identical to Study 1. Students also followed the same procedures as in Study 1, but with the exception that the four imagery and performance sessions were held twice a week for two weeks, rather than once a week for four weeks as in Study 1. The baseline performance measures were taken one week prior to the beginning of imagery and performance sessions. Overall, the students participated in this study for a total of three weeks and underwent the same procedures as those students in Study 1. The control group In this study completed their questionnaire (as described in Study 1) before their first performance task of the second week. These subjects had more experience than the high school student sample with the basketball shooting task, due to the I act that they had just completed a course on the rules, positions, and techniques of the basketball game.

Results

Study One. Means of the successful basket shots for each of the three treatment groups and the control for the baseline and four trials are presented in Figure 1.

[Figure 1 ILLUSTRATION OMITTED]

Repeated Measures (RM) ANCOVA was applied to the data with treatment as a between subjects factor, four trials as a repeated within subjects factor, and baseline measure as a covariate (despite the random assignment, after observing baseline means). The analysis revealed that only the trial factor reached a statistical significance F(3,21 0)=3.46; p [is less than] .02. Examination of the trial means across the four groups has indicated that on the average the performance Improved from 4.68 + 2.68 (first trial) to 5.57 + 3.09 (fourth trial), which is about a 19% total increase and a 5.93% relative increase [(5.57/15)100 - (4.68/15)100=5.93%]. Neither the treatment nor Its interaction with the trial factor were statistically significant.

Examination of the imagery vividness of movement has shown that all four groups (three experimental treatments plus control group) did not differ each from the other in the vividness of the imaged movements (body parts, movement of body parts, movement of the whole body imagining myself and imagining someone else) for the first trial.

RM-ANOVAs for each of the VMIQ sections (over four trials) have indicated that the three treatment groups did not differ significantly from each other during the four trials. Also, the trial effect was found to be insignificant. Means show that on the average the vividness of the body parts and movements of the body parts was about 70% of the maximal possible vividness ("almost perfectly clear and as vivid as normal vision").

Additional analyses were applied to the data in order to detect possible differences between internal and external (imagery perspective) vividness in the four trials for the three experimental groups. Treatment was used as a between subjects factor, and vividness of imagery perspective (internal-external) was used as the first within subjects factor, along with the four performance trials within each factors being used as a second trial factor. The mixed ANOVA design was applied separately to the vividness of the body parts, movement of the body parts, and movement of the whole body.

The results revealed significant effects only for the vividness of the body parts; imagery perspective X performance trials, F(3,129)=4.08; p [is less than] .008 and treatment X imagery perspective X performance trials, F(6,129)=2.22; p [is less than] .04. These interactions are presented in Figure 2.

[Figure 2 ILLUSTRATION OMITTED]

The analysis revealed that subjects exposed to ski imagery, improved significantly in the imagery perspective of external vividness of body parts from the first to the fourth trials. The reverse was found in the successful free throw treatment. This treatment showed a similar, but insignificant trend for internal vividness of the body parts.

Study 2

Similar analyses to those of Study 1 were applied in Study 2. The means of the four treatments for each of the four performance trials are presented in Figure 3.

[Figure 3 ILLUSTRATION OMITTED]

The RM-ANCOVA has indicated that neither the treatment nor the trial and their interaction were statistically significant (p [is greater than] .05) for the performance task. All groups remained consistent in their improvement of performance across the four trials (about 35% 38% success).

The RM-ANOVAs applied to the VMIQ sections of imaging one-self's body parts, the movement of body parts, and the movement of the whole body, have shown trial effects F(3,30)=3.39; p [is less than] .03, F(3,30)=6.97; p [is less than] .001, and F(3,27)=3.74; p [is less than] .02 respectively. On the average, the vividness of imagining one-self's body parts improved by 13%, movement of body parts by 18%, and movement of the whole body by 20%.

Trial effects were also obtained for imagining someone else's body parts F(3,30)=2.99; p [is less than] .05 and the movement of body parts F(3,30)=4.23; p [is less than] .01. On the average the vividness of imagining someone else's body parts improved by 12%, and the movement of body parts improved by 11%. It should be noted that the vividness of movement in imagery by the subjects in this study was about 90% of the maximal vividness ("almost perfectly clear and as vivid as normal vision").

The ANOVA applied to the imagery perspectives (internal-external) of vividness was similar to those applied in Study 1. This ANOVA revealed significant effects for imagery perspectives of the body parts, F(1,10)=9.81; p [is less than]. 01, the movement of body parts, F(1,10)=8.63; p [is less than] .01, and the movement of the whole body, F(1,9)=15.93; p [is less than] .003. These effects are shown in Figure 4.

[Figure 4 ILLUSTRATION OMITTED]

It is here that on the average, the vividness of the external imagery perspective was rated higher than the internal imagery perspective of the body parts, the movement of body parts, and the movement of the whole body, The analyses also revealed significant trial effects for the three components of the VMIQ (across internal/external imagery perspectives): the body parts, F(3,30)=3.59; p [is less than] .02; the movement of body parts, F(3,30)=8.48; p [is less than] .00; and the movement of the whole body F(3,27)=4.55; p [is less than] .01. Thus the vividness of imagery perspectives (internal-external) of the three components of the VMIQ increased significantly from the first to the fourth trial, Figure 5 presents these effects.

[Figure 5 ILLUSTRATION OMITTED]

Discussion

The present studies investigated the question of whether manipulation of a mental technique such as imagery can enhance a physical skill such as a basketball throw. Imagery was taught to 3 groups of subjects using three different methods: (1) watching and imagining successful throws, (2) watching and imagining unsuccessful throws, and (3) watching and imagining unrelated skills. The subjects in both studies were inexperienced in the basketball skill and therefore may be considered novices. It was hypothesized that despite their lack of experience, experiencing successful throws through imagery would create a sense of the action and would result in enhanced internal vividness of the images, which were to enhance physical performance (Hecker & Kaczor, 1988). The studies were aimed at testing this main hypothesis, which was based on the bioinformational theory (Hecker & Kaczor, 1988; Lang, 1977, 1979).

In this investigation, we also attempted to (a) examine whether imagery of an unsuccessful action has the potential of extinguishing a maladaptive behavior and enhancing performance, in line with the implosive therapy applied in the psychotherapeutic domain (Karoly & Kanfer, 1982) and related findings regarding the physical skill of golf-putting (Woolfolk et al., 1983, cited by Suinn, 1993); (b) to examine whether practicing neutral imagery such as skiing may enhance physical performance similarly or differently from practicing unsuccessful throws; and (c) to examine whether practicing different images enhances the vividness of the body parts and their smooth movement (more internal than external), and consequently enhances performance through kinesthetic feelings of the movements being imagined (Jacobson, 1932; Mumford & Hall, 1985).

The findings of the present study suggest that practicing imagery of a motor skill which is not yet mastered by the subjects may result in two possible outcomes: Study 1 indicates that while imagery vividness is sustained following a once a week practice by all the groups, physical performance which requires eye-hand coordination may increase as a result of improved acquaintance with the task. However, study 2 indicates that while imagery vividness increased at a high level following a twice-a-week practice of imagery, physical performance was sustained at the same level throughout the four trials. This indicates an improved acquaintance with imagery but not with the eye-hand coordination task. These two effects are summarized in Table 1.

Table 1 Effects of Practicing Imagery of A Novel Task Which Requires Eye-hand Coordination

Study Imagery Imagery Motor
 Practice Vividness Performance Outcome

1 once a week sustained increased improved
 acquaintance
 with task

2 twice a week increased sustained improved
 acquaintance
 with imagery

These two possible outcomes are in disagreement with our a priori expectations. Since progress in shooting throws through four weeks was similar in the three experimental groups as well as in the control group (the one not subjected to any imagery manipulation), performance enhancement may be attributed to better acquaintance with the task. Neither the bioinformational theory (Lang, 1977, 1979) nor the principles of implosive therapy (Karoly & Kanfer, 1982) and the related rationale of Woolfolk et al. (1983) can be used as reasonable explanations of the present results.

The hypothesis that the high level vividness of the external and more so of the internal orientation would contribute to some extent to performance enhancement (Smith, 1987) is not supported by the present results, because vividness remained consistently high across all four trials. However, it can be argued that only experienced subjects, who are well acquainted with the physical task and at the same time feel and experience the movement through imagery, may improve in such a skill (Hecker & Kaczor, 1988). It seems that vividness in itself is not sufficient to improve performance, but mentally experiencing physical practice may enhance physical performance when the skill is well mastered. Thus, vividness is needed to support the process, but it cannot stand by itself. It is possible that subjects exposed to imagery "saw" the throws to the basket very vividly (from both internal and external perspectives), but did not feel it. In any case, substantial experience together with internal feeling of the action are probably needed to enhance performance. In study 1, neither condition (experience, feeling the action) was fulfilled.

Study 2 revealed that external orientation of the images increased, internal images remained consistent across all four trials, and eye-hand coordination task did not improve whatsoever. These results may be explained by (a) subjects being novice, that is, they have not yet sufficiently learned the task; (b) an increase in external vividness not being necessarily related to physical performance enhancement; (c) subjects not feeling the action (similar to the subjects in study 1); (d) short imagery period and insufficient number of trials

The results of study 2 did not confirm the hypothesis that the more vivid the image, the better the performance outcome (Start & Richardson, 1964). However, this might be the case with expert athletes who were found to use internal imagery more often than external imagery (Hall et al., 1990; Mahoney & Avener, 1977), in comparison to recreational athletes, who tended to use external imagery more frequently (Epstein, 1980; Smith, 1983). The fact that motor tasks are more receptive to internal imagery (Smith, 1987: Suinn. 1993) is probably true, but this is not a sufficient condition to enhance performance. It seems that one should actually feel the imaged action in order to subsequently improve performance of a skilled movement. Thus, the more the subject is skilled and the more acquainted he or she is with the physical task, the greater probability of him/her achieving actual physical progress through internal imagery.

The practicing sport psychologist and the coach should be aware of the consequences of applying imagery to novice subjects. The three imagery methods applied in the present research did not decrease performance, as compared to the groups which did not practice imagery. However, it seems that more time should be given to imagery and practice in order to bring about a notable improvement in performance (Smith, 1987; Weinberg, 1982). This applies more to novice athletes, with the process probably being shorter when skilled athletes are considered. In any case, the present suggestions call for further research in this domain.

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