Figure 1.

Sample trial sequence in the present Simon-type manual reaching task. The target was randomly defined by color (red) or shape (square), with the correct motor response (left vs right hand) being defined, independently of the target-defining attribute (color vs shape), by the orientation of the stripes inside the target (vertical vs horizontal). Target positions were selected randomly, on a trial-by-trial basis, from all but the central and the two outer positions.