Association between a color and a manual response activation modulates the response planning of typically developing children in a subsequent Simon task.

The Simon effect usually refers to the observation that responding to a nonspatial feature of a stimulus is faster when the position of the stimulus (task-irrelevant) matches the position of the to-be-executed response. The Simon effect can disappear when the Simon task is preceded by a spatial compatibility task with an incompatible mapping. In this experiment, during a preliminary phase, 20 children had to decide whether the outline of a colored stimulus was dotted or continuous. Green stimuli were presented exclusively on the right, whereas red stimuli were presented on the left (the color was task-irrelevant). The participants then had to perform a Simon task. When the instructions required them to press either the left or the right button for red or green stimuli, respectively (Group A), the Simon effect on response latencies was not significant. With the opposite instructions (the right or left button for red or green stimuli, respectively; Group B), the Simon effect was significant on response latencies. The Simon effect was significant on movement times for both groups. These results suggest that during the preliminary phase, each color became associated with the manual response automatically activated by that color’s position. In the subsequent Simon task, the presentation of the color activated the associated response. This modulated the planning of the to-be-executed response.