Does psychological refractoriness depend on the similarity of the required responses?

The purpose of this study was to examine whether the similarity of R1 and R2 is a moderating variable in the psychological refractoriness effect. 10 subjects were required to react and produce the sequence of two homogeneous or heterogeneous peak forces as soon as possible after Stimulus 1 and 2 separated by variable interstimulus intervals. The heterogeneous condition produced a significantly longer RT and premotor time to Stimulus 2 than the control condition for the intervals up to 200 msec. The homogeneous condition, however, produced a significantly shorter RT and premotor time to Stimulus 2 than the control condition when the intervals were from 100 to 1000 msec. These findings suggest that the psychological refractoriness effect depends on the similarity of the required responses. These results were discussed from the view of a limited-capacity mechanism during the response-programming stage.