INTERACTIONS - TIMING AND FORCE CONTROL OF FINGER-TAPPING SEQUENCES

This study examined effects of combinations of intertap interval and m uscle force on interactions between two factors in sequences of equall y paced finger taps. 12 male college students tapped a force plate con nected to strain gauges. Subjects firstly tapped the plate at a prefer red pace and force for 12 sec. Next, subjects tapped the plate by half or double the preferred pace. A series of finger-tapping tasks then c onsisted of nine combinations of pace and force. Analysis showed that, although variations in intertap interval were considerably accurately controlled across conditions, those in peak forces were not. Movement timing of tapping sequences hence appeared to be independent of force control. For six of 12 subjects, on the other hand, positive correlat ions between spontaneous variations in intertap interval and in forces were noted. Then, although motor timing was independent of force cont rol in conditions of low pace and weak force, there were strong intera ctions between the two factors under high pace conditions.