Retention and adaptive control of force pattern on a finger-tapping sequence with an attenuated force tap

The present study was designed to examine the retention and adaptive contro l of a force pattern in the scaling of speed profiles in a finger-tapping s equence with an attenuated tap. On practice trials, 11 college students tap ped on a force plate connected to strain gauges with feedback. On test tria ls, participants recalled the force pattern (200 gm-200 gm-200 gm-100 gm) a nd the intertap interval (400 msec.) acquired during practice without feedb ack (recalled task). Then, participants adaptively tapped the acquired forc e pattern at the half (speeded task) and double (slowed task) the intertap interval acquired during the practice. Analyses showed that mean peak force s increased across tasks as the tapping speed was slowed down. Mean peak fo rces at the first three tap positions in sequence were smaller than the req uired forces in both the recall and speeded tasks. So, although the slowed task had the lowest ratio of forces in serial positions 1:4, 2:4, and 3:4, the ratios were less than 2 across tasks. These indicated that changing to a slow pace creates a more difficult adaptive task than changing to a fast pace, and further that a serial force pattern with an attenuated force crea tes a more difficult motor task for fine control than that with an accentua ted-force.