REACTION-TIME ANALYSIS OF PROGRAMMED CONTROL OF SHORT, RAPID AIMING MOVEMENTS

Reaction time, fractionated reaction time (premotor and motor time), and movement time were recorded during performance of a rapid aiming movement (11 mm in amplitude) to a circular target. Independent variables were target diameter (2 or 64 mm) and reaction time condition (simple or choice). Fifty-two subjects performed 16 practice and 24 performance trials under one of four possible experimental combinations (13 subjects per combination) in a 2 × 2 design. Reaction time correlated highly with premotor time (r =.99) but not with motor time (r =.31). Choice reaction time and its premotor time component were dependent upon target diameter, but simple reaction time and its premotor time component were not. However, choice and simple motor time were not differentially affected by target diameter. As expected, movement time was longer for the small target than for the large target. Taken together, the reaction time results were interpreted as support for Klapp’s (1975) hypothesis that increases in choice reaction time for rapid movements to a small target are due to increases in the time needed for programing the response. © 1979 Taylor 8 Francis Group, LLC.