INTERSENSORY FACILITATION OF REACTION-TIME - EVALUATION OF COUNTER AND DIFFUSION COACTIVATION MODELS

In a simple reaction time experiment a subject's task is to react to s timuli from three different modalities (visual, auditory, tactile) whe n any of the stimuli is presented alone, as a pair from two different modalities, or as a triple from all three modalities. The shorter reac tion time to double stimuli compared to reaction time to single stimul i or the shorter reaction time to triple stimuli compared to reaction time to double and single stimuli is called ''intersensory facilitatio n of reaction time.'' Two models were considered to explain this pheno menon: a counter model (Poisson superposition) and a diffusion model ( Ornstein-Uhlenbeck process). Both models gave an excellent fit on the level of mean reaction times. (C) 1995 Academic Press, Inc.