Effects of Induced Muscle Tension and Auditory Stimulation on Tachistoscopic Perception

Abstract

The effect of accessory stimulation upon tachistoscopic perception of geometric figures was studied. In Exp. I 32 Ss were tested on two successive days in a complete factorial design (Subjects × Treatments) in which degree of induced muscle tension (IMT) and level of task difficulty were manipulated. An IMT level of ½ of maximum resulted in significantly ( p < .01) improved visual perception. In Exp. II artificial pupils were employed to test the hypothesis that improved performance was due to pupil dilation. Eight Ss from Exp. I were tested on five successive days and performance at ½ of maximum IMT was again significantly ( p < .05) improved, thus precluding pupil dilation as the reason for the results obtained in Exp. I. In Exp. II performance at the middle level of task difficulty benefited significantly ( p < .05) from IMT. Exp. III investigated the effects of four levels of auditory stimulation (white noise) on tachistoscopic perception in a new group of 32 Ss. Perception was significantly ( p < .05) improved with the ¼ of maximum noise level at the easiest level of difficulty. Results were interpreted within the framework of the activation concept. Recent neurophysiological data point to the ascending reticular activating system as a possible mediator which could influence cortical and retinal areas in the facilitation of tasks such as tachistoscopic perception.