Refractoriness of on Extended Movement to Directional Change

An extended movement was used to compare the memory-drum and single-channel definitions of psychological refractoriness. The basic movement In response to the first signal (S1) was a forward lunge and a concurrent arm swing through a target string. The response to the second signal (S2) was a reversal of the original movement The interstimulus Interval (ISI) ranged from .10 - .70 sec. in .10-sec. steps. The hypothesis that refractoriness of the reversal movement would decrease as ISI shortened was confirmed by the fact that error frequencies decreased significantly and substantially with decreasing IS I. The availability of some residual capacity to deal with S2 during the refractory period was also indicated by an examination of the relationship between RT2 and the interval between S2 and RT1. This departure from the classical single-channel model shows some agreement with the neuromotor-programming theory.