The premotor theory of attention as an account for the Simon effect.

The Simon effect refers to the phenomenon that responses are faster when the irrelevant location of a stimulus corresponds with the response location than when these locations do not correspond. In the current paper we examined the viability of an updated version of the premotor theory of attention (PMTA) as an account for the Simon effect. Two predictions were evaluated. First, in the case of focused attention at the relevant target position a strong reduction of the Simon effect should be observed as the Simon effect according to PMTA crucially depends on attentional orienting. Secondly, if attention is directed towards a location then this orienting by itself should already be sufficient for producing a Simon effect, as stimulus presence is not required. Our data confirmed these predictions thereby supporting the relevance of the PMTA for the Simon effect.