Further Tests of a Two-State Model for Choice Reaction Times

Falmagne proposed that choice reaction times can be described by a simple model involving two states of perceptual-motor preparation. Lupker and Theios found support for the model in an M-choice (w = 4, 6) reaction time task in which stimulus presentation probability was varied as IT for one stimulus, but was constrained as (1 —*•) / (»— 1) for all the remaining stimuli. The present experiments involve fourand six-choice tasks in which the stimuli differ in their individual presentation probabilities. Sequential mean reaction times and various properties of the reaction time distributions are considered. The model was able to predict with reasonable accuracy all the sequential mean reaction times except those for alternating stimulus sequences. The fixed point and other distributional properties seemed to hold on a general level. However, detailed inspection revealed a few systematic deviations between the data and distributional properties predicted by the two-state model.