On stage robustness and response selection routes: Further evidence

Abstract

A series of choice reaction time tasks have been used in an experiment to investigate the processing stages of stimulus identification and response selection, and the relationship between them. It was shown that the duration of both processes, manipulated by stimulus discriminability and stimulus-response compatibility, remained independent under various task conditions and demonstrated the robustness of the stage structure. Findings pertinent to response selection replicated two effects: (1) a subadditive interaction between stimulus-response compatibility and task uncertainty (i.e., presenting (in)compatible S-R pairs blockwise or mixed in a session), and (2) an overadditive interaction between stimulus-response compatibility and the number of stimulus-response alternatives when (in)compatible S-R pairs were presented blockwise. However, it appeared that presenting the S-R pairs mixed in a session the latter interaction became additive. A processing route conception suggested earlier (Frith and Done, 1986; Van Duren and Sanders, 1988), is used in conjunction with the dimensional overlap model proposed by Kornblum et al. (1990) to explain these three main findings in one, subject driven, effective route model.