The Effects of Mental Practice on Motor Skill Performance: Critical Evaluation and Meta-Analysis

Empirical research suggests that mental practice may enhance the performance of motor skills. Many variables have been shown to mediate the size and direction of the mental practice effects. The purpose of the present study is to provide an overview of research examining the role played by these variables in mediating the effectiveness of mental practice. In order to integrate the findings in the literature and to further analyze the relative contributions of each of these variables, a meta-analysis was performed according to the procedure outlined by Smith, Glass, and Miller. Twenty-one studies that met the criteria of having both an adequate control and a mental practice alone group were included in the meta-analysis. The forty-four separate effect sizes resulted in an overall average effect size of .68, (SD = .11) indicating that there is a significant benefit to performance of using mental practice over no practice. A series of General Linear Models revealed that the use of “internal” imagery produced a larger average effect size than the use of “external” imagery, and that mental practice sessions of less than one minute or between ten and fifteen minutes in length produced a larger average effect size than sessions of three to five minutes in length. These findings suggest the complexity of the relationship between variables that influence mental practice.

EMG Quantification of Mental Rehearsal

EMG response to mental rehearsal was investigated in 5 athletes who reported the ability to image “internally”. Rehearsal was associated with increases in EMG activity relative to resting levels and ranging from 45 to 178%. Configuration of the EMG profile was highly congruent with the imaged event. Congruency of the imaged EMG profile with EMG profiles of the actual performance was demonstrated. Actual time taken to perform and the rehearsal time also exhibited congruency. Findings suggest methods of assessing the mental rehearsal process and research paradigms with implications for specific mental-training techniques.

The Private Personality

Reflecting the reemergence of interest in conscious experience that characterizes modern psychology, this article examines a range of issues that are part of the study of the private personality. It is proposed that in formulating a model of individual differences in ongoing conscious experience, we must consider the basic systems through which information is initially received and stored, since variations in processing styles may already lead to the structural and content variations that ultimately shape the unique sense of a private personality. The psychophysiological, affective, and cognitive systems are reviewed with reference to the kinds of input they provide. These include variations in response to bodily cues (e.g., repressive defensiveness and hardiness) or in the styles of cognitive complexity. Research possibilities for linking these stylistic variations at the receptive pole to centrally-generated stimulation by means of repeated measurements, psychometric instruments, and thought-samples of ongoing consciousness are considered with the ultimate aim of clarifying processes of schema formation.

Mood Congruity in Children: Effects of Age, Imagery Capability, and Demand Characteristics

The present study was designed to determine: (1) whether mood congruity shows up the same way in children of different ages; (2) whether experimental mood induction by a mental imagery procedure is more effective in subjects with high mental imagery capabilities; and (3) whether "acting as if one is happy or sad" results in the same biases as the real mood induction procedure. Five different groups were assembled, which received either a happy or a sad mood induction, a happy or a sad simulation instruction or a neutral instruction (control group). Instruction effects were measured on a task in which all subjects had to judge drawings of ambiguous facial expressions.

Mood effects could be demonstrated for younger (n= 152, mean age 6; 11) as well as older children (n = 151, mean age 10;9), but only for good imagers, not for bad ones. Judgements of happy and sad children were biased in a direction congruent to the induced mood state. This mood congruity effect was not the result of demand characteristics as it did not show up in both simulation groups (i.e. children who were simply "acting as if they were happy or sad").

Movement and stretching imagery during flexibility training

The aim of this study was to examine the effect of movement and stretching imagery on increases in flexibility. Thirty volunteers took part in a 4 week flexibility training programme. They were randomly assigned to one of three groups: (1) movement imagery, where participants imagined moving the limb they were stretching; (2) stretching imagery, where participants imagined the physiological processes involved in stretching the muscle; and (3) control, where participants did not engage in mental imagery. Active and passive range of motion around the hip was assessed before and after the programme. Participants provided specific ratings of vividness and comfort throughout the programme. Results showed significant increases in flexibility over time, but no differences between the three groups. A significant relationship was found, however, between improved flexibility and vividness ratings in the movement imagery group. Furthermore, both imagery groups scored significantly higher than the control group on levels of comfort, with the movement imagery group also scoring significantly higher than the stretching imagery group. We conclude that the imagery had stronger psychological than physiological effects, but that there is potential for enhancing physiological effects by maximizing imagery vividness, particularly for movement imagery.