Figure 1.

(A) Participants were instructed to press the left button in response to a blue circle and a right button in response to a green circle (dashed line). Responses are also driven by an irrelevant stimulus dimension, i.e. circle location, as indicated by the solid line. For corresponding trials, both relevant (i.e. colour) and irrelevant (i.e. location) stimulus dimensions activate the correct action. In non-corresponding trials, the irrelevant dimension activates an incorrect response, which interferes with selection of the correct response. (B) Depiction of the temporal and response elements of the task, as well as all possible stimulus configurations [corresponding (C) and non-corresponding (NC)] that were presented randomly and with equiprobability throughout each block of trials. ITI = inter-trial interval; S–R = stimulus–response.