Visual and motor effects in inhibition of return

Inhibition of return (IOR) refers to slowed reaction times (RTs) when a tar get appears in the same rather than a different location as a preceding sti mulus. The present study tested the hypothesis that IOR reflects a motor bi as rather than a perceptual deficit. Two signals (S1 and S2) were presented on each trial. These signals were peripheral onsets or central arrows. The responses required to S1 and S2 were, respectively, no response-manual, ma nual-manual, saccadic-manual, no response-saccadic, manual-saccadic, and sa ccadic-saccadic. Uniting perceptual: and motor bias views of IOR, the resul ts demonstrated inhibition for responding to (a) peripheral signals when th e eyes remained fixed (slowed visual processing) and (b) both peripheral an d central signals when the eyes moved (slowed motor production). However, t he results also emphasized that the nature of IOR depends fundamentally on the response modality used to reveal its influence.