Fig. 1.

Setup and design. Pairs of participants performed a two-choice version of the Simon tasks next to each other, responding to the color of visual stimuli on the left or right side of the screen with a left or right button press. The mapping of stimulus and response side was manipulated as a between-subject factor. In the corresponding mapping group (left panels), stimuli were always congruent (upper left panel) or incongruent (lower left panel) for both coactors. In the non-corresponding mapping group (right panels), coactors had different mappings such that the same stimulus was at the same time congruent for one participant and incongruent for the other participant