The interference effect of simultaneous vocalization on manual reaction time.

Abstract

Simple reaction times (RTs) of the left or right hand with or without simultaneous vocalization were examined in 14 righthanded subjects. RTs of the simultaneous tasks were longer than those of the single tasks and slowing of RT was larger on the manual than vocal response, particularly on the right side. The results are interpreted as reflecting a different mode of processing in the left and right hemispheres. reaction time; interference effect; hemispheric differentiation Recent studies reported that the manual performance could be varied with the simultaneous speaking. The performance with speaking was less effective than that without speaking, especially on the right hand (Kinsbourne and Cook 1971;Hicks 1975). This interference would be due to a functional overlap of speaking and motor control in the left hemisphere (Lomas and Kimura 1976). Several manual tasks such as dowel balancing (Kinsbourne and Cook 1971; Lomas and Kimura 1976), finger tapping or button-pressing Ashton 1975, 1978;Bowers et al. 1978) and simple reaction time (RT) (Low and Rebert 1978;Rizzolatti et al. 1979) were examined with concurrent mental or verbal performance to analyse the interference effect. Bilateral simultaneous movements took more time to produce motor effect than the separated movement of either arm alone, but the slowing of RT in the simultaneous movement was not different in the left and the right arm , and the degree of interference was the same in the left and right hand . In the present study, we investigated the simple RT of the left or right hand with simultaneous vocalization, and analysed a possible hemispheric differentiation of the interference effect of vocalization on motor performance. METHODThe experiments were performed on 14 right-handed laboratory staffs, seven male and seven female, aged from 21 to 43 years.In a quiet room the subject was seated comfortably on a chair with eyes closed and the forearms rested on a desk. The subject was first given a warning verbal signal

The interference effect of simultaneous vocalization on reaction time of hand and foot.

“…The interference occurs not only between psychologically different tasks, but also between the responses made by somatotopically different parts (Nakamura et al 1981). The site at which the interference occurs in the CNS has not been known.…”

“…The experimental procedure was already reported in detail (Nakamura et al 1981). In short, the subject responded to the peep sound after a warning signal with extension of right fingers or toes, or with vocalization.…”