Effect of concurrent visual feedback on acquisition of a weightlifting skill

Practice in front of a mirror is a common procedure for activities such as dance, gymnastics, and other sports. The purpose of this study was to examine the effect that performing with concurrent visual feedback from a mirror had on the acquisition of the power clean movement. 18 college-age males who had no prior experience with the power clean movement served as subjects who were assigned to one of two groups. One group had use of a mirror during the practice trials and the other practiced without the mirror. All subjects viewed an instructional videotape and had practice trials. All subjects were evaluated for proper technique on a pretest, a posttest without the mirror, and a posttest with the mirror. Analysis showed a significant difference between pre- and posttest performances for both groups and a significant difference between groups on the posttest performances with the mirror. Evidently the videotaped instruction was sufficient to allow both groups to improve in performance of the power clean. Differences in posttest performances with the mirror reflected the type of feedback (with or without the mirror) available during training.     

Visual Elaboration Scale as a measure of imagery

We studied the correlation of one measure of imagery ability, the Visual Elaboration Scale, with two others, absorption of image and effort required to form a mental image. Significant correlations were obtained between the Visual Elaboration Scale and the other scales, with the exception of Absorption for women.     

INDIVIDUAL AND SITUATIONAL CORRELATES OF WHISTLE-BLOWING

Although popular interest in whistle-blowing continues to increase, little is known about why some employees who observe wrongdoing report it, while others do not. In the present study, we analyze archival survey data from individuals who observed wrongdoing in any of 22 organizations. Results are generally consistent with predictions based on a model of whistle-blowing as a type of prosocial behavior. Whistle-blowing was more likely when observers of wrongdoing (1) held professional positions, (2) had more positive reactions to their work, (3) had longer service, (4) were recently recognized for good performance, (5) were male (though race was unrelated to whistle-blowing), (6) were members of larger work groups, and (7) were employed by organizations perceived by others to be responsive to complaints. Implications for research and practice are described.     

Sample size determinations for the two rater kappa statistic

This paper gives a method for determining a sample size that will achieve a prespecified bound on confidence interval width for the interrater agreement measure,. The same results can be used when a prespecified power is desired for testing hypotheses about the value of kappa. An example from the literature is used to illustrate the methods proposed here.