A Diffusion Model Analysis of the Response-Effect Compatibility Effect

Humans act goal-oriented, and this idea is at the core of ideomotor theory (IT), which claims that actions are selected by mentally anticipating the sensory consequences brought about by the respective bodily movement (i.e., their action effects). Evidence for this effect anticipation mainly derives from the response-effect (R-E) compatibility (REC) paradigm: In the spatial domain, for example, a left response is produced faster (and sometimes less error-prone) if followed by a compatible left rather than an incompatible right action effect. In the present study, we employed the diffusion model to elucidate the reasons for this observation. To this end, we reanalyzed data from the seminal study by Kunde (2001) and from a new experiment. The overall results suggest that REC affects drift rate. This result fits well with conceptualizing REC as an endogenously created case of stimulus-response compatibility (SRC). Several consequences of this view are discussed against the background of available empirical results.