Preview and Movement as Determiners of Timing a Discrete Motor Response

Abstract

Preview and voluntary movement in discrete motor response timing was investigated. Subjects lifted the right index finger from a response key when a moving pointer (1.260-sec travel time) passed directly under a stationary pointer. Four groups of 15 male and female college students performed 150 trials of the timing task with knowledge of results after each trial under one of four conditions: (a) preview of the moving pointer and left-arm movement, (b) preview of the moving pointer but no left-arm movement, (c) left-arm movement but no preview, and (d) no preview and no left-arm movement. Preview led to greater timing accuracy and consistency than did either no preview or movement. Movement did not influence timing accuracy, but resulted in greater timing consistency in the absence of preview. When preview and movement were available at the same time, the subject relied on preview to keep time.