Automatic aftereffects in two-choice reaction time: A mathematical representation of some concepts

Developed a mathematical single-decay model to describe sequential effects in 2-choice RT experiments with a short response-stimulus interval (RSI). It is suggested that in conditions with short RSIs, it is automatic aftereffects that dominate sequential effects, not subjective expectancy. The model premises 3 components of automatic aftereffects--facilitation, inhibition, and noise--with a common decay factor. Influence of RSI and practice on sequential effects are examined and related to parameter changes in the proposed model in 3 experiments with 76 Ss. Findings indicate that the decrease of automatic aftereffects with increasing RSIs was primarily ascribed to an increasing decay factor. The parameter representation of the model clarified the disappearance of automatic aftereffects with practice revealing a gradual fading of inhibition in the initial stages of practice, together with a slower decrease of the facilitation effect. It is contended that the single-decay model provides an explanation for the processes involved in compatible 2-choice RT with short RSIs. (36 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1984 American Psychological Association.SCOPUS: ar.j