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Perceptual augmentation and reduction were considered contrasting styles of Stimulus Intensity Modulation. Differences in perceived exertion between augmenters and reducers were determined for three cycle ergometer work loads. Subjects were 20 males having similar physiological characteristics. Stimulus Intensity Modulation was determined by kinesthetic figural aftereffect. Augmenters rated their perceptions of physical exertion to be more intense than reducers at 450, 750 and 1050 kpm/min. Differences in physiological responses between augmenters and reducers were not significant at the three work loads. Style of Stimulus Intensity Modulation appeared differentially to influence perceived exertion at the work levels studied.

The influence of pretest hand-resting time and induction time on kinesthetic aftereffect was determined for 22 males and females. Aftereffect was assessed with the apparatus of Koehler and Dinnerstein (1947). Three separate tests of aftereffect were administered. Each was preceded by either a 10-, 20-, or 30-min. hand-resting period. Significant differences in aftereffect were not found between pretest conditions. Scores were also determined for varying induction times at each pretest condition. Induction periods totaling 90-, 180-, and 300-sec. were used. Aftereffect was significantly less pronounced following 90 than 180 sec. of induction for the 10-and 20-min. pretest conditions but was the same following 90, 180, and 300 sec. of induction for the 30-min. condition. Results indicated that less than 300 sec. of induction could be used regardless of the duration of the pretest period. However, because the internal validity of the 180-sec. score was significantly better than the 90-sec. score, it was concluded that at least 180 sec. of induction were needed.