REFRACTORY PERIOD OF C-REACTIONS

On each trial the presentation of a letter calling either a key-pressing response or abstention (Donders' c-reaction) was followed, after an interstimulus interval (ISI) varying at random over the range 0-700 msec., by the onset of 1 of 2 lamps calling for the pressure of 1 of 2 keys. The problem was to know if the 2nd reaction would be delayed more after positive than after negative 1st stimuli. Exp. I, where 2 stimuli, 1 positive and 1 negative, were used for the c-reaction, gave ambiguous results. It seemed possible that the instructions and the payoff system had led some Ss to prepare selectively for the positive stimulus. To make this strategy more difficult, 4 stimuli, 2 negative and 2 positive, calling for the choice between 1 of 2 keys, were used for the c-reaction in Exp. II. Each of the 4 Ss had longer delays after the positive 1st stimuli. It was concluded that analysis of the stimulus and execution of the response contribute independent components to the refractory period. Data from the positive trials were found to be in general agreement with a single channel interpretation of refractoriness but not with the strong version assuming no overlap of occupation times, and confirmed earlier suggestions that some residual capacity is still available during the refractory period. (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1969 American Psychological Association.