Two experiments were conducted to investigate the psychological refractory period (PRP), a delay induced into the second of two reaction times (RT) when the interstimulus interval (ISI) is short. In Experiment 1, time and event uncertainty were factorially varied by providing or not providing S with foreknowledge of the ISI and the order in which the two events would occur, respectively. ISIs of 0, 50, 100, 200, and 400 msec were used. Time and event uncertainty produced independent degradation of both RTs. Also, the second RT (RT 2) was delayed at 50 msec ISI when both time and event certainty were present. Experiment 2 attempted to replicate this latter finding using ISIs of 0, 25, 50, 75, and 100 msec. Delays in RT 2 were found for the middle three values of ISI. These results were interpreted as supporting a modified single channel theory of the PRP.
ASJC Scopus subject areas
- Experimental and Cognitive Psychology
- Sensory Systems