Retention of Relative Force in the Scaling of a Serial Force Pattern

The present study was designed to examine the retention of relative force in the scaling of a serial force pattern in finger-tapping sequences. On practice trials, 11 male college students tapped a force plate connected to strain gauges which provided feedback. On test trials, subjects recalled both the force pattern (100 g-100 g-100 g-300 g) and intertap interval (400 msec.) acquired during practice without feedback (recalled task) and then produced a halved (halved task) or doubled-force (doubled task) at the fixed intertap interval. Analysis showed that, although there was no difference for absolute forces between the recalled task and the halved task, the forces at the doubled task were three times as great as those at the recalled task. For relative forces, on the other hand, although there was no difference among the three tasks, the force ratios were closer to 1:1:1:2 than 1:1:1:3. This indicated that the scaling of force pattern was a more difficult adaptive task than that of the intertap interval in the previous study (Inui, Ishida, & Yamanishi, 1999).