Task complexity and advance information effects on preparation and exectution of voluntary movements

Abstract

Recent investigations regarding the preparation and execution of simple and complex movements (Corcos, 1984; Fischman, 1984; Peters, 1985) have led to some new questions about interlimb coordination. In situations where each limb executes a task unequal in difficulty, the constraint on one limb appears to adversely affect the contralateral limb. This study involved two experiments and addressed the questions of how an individual prepares two distinctly different movements prior to a stimulus to respond and how quickly and effectively the movements can be executed. Experiment 1 focused on advance information effects on reaction time (RT) and movement time (MT) with respect to task complexity using the precuing technique. Fractionated RT and kinematic data analysis were used in Experiment 2 to delineate premotor or decision time from motor time and response time. Differences between arm and direction precues were found to be in the motor time of the responses suggesting physiological and/or electromechanical mechanisms take longer to initiate an observable response after a direction precue. Mean RTs were greatest for the complex movement condition, followed by the dissimilar movement condition. This supports the idea that preparation of complex movements, even when they are not executed, increases RT. An increase in RT of this nature supports the hierarchical editor model proposed by Rosenbaum, Inhoff, and Gordon (1984).