The effect of irrelevant response dimension on stimulus response compatibility

The well-known Stroop, Simon, and Eriksen flanker effects reflect the influence of an irrelevant dimension of a stimulus on task performance. In contrast, this study investigated the effect of an irrelevant (color) dimension of a response on performance. In Experiment 1, participants performed a color-discrimination Simon task with left and right responses. The novel feature of the experiment was that two-colored labels were presented at the bottom of the display, on the left and right side respectively, which were irrelevant to the task and had nothing to do with response keys. The results revealed a Color Compatibility effect. Participants responded faster and more accurately when the color of the label appearing on the same side (left or right) as the correct response matched the color of the stimulus than when it did not. Experiment 2A replicated the Color Compatibility effect. Experiment 2B showed that the Color Compatibility effect in reaction times disappeared when color was irrelevant to both the stimulus and the response. The results suggest that the presence of an irrelevant color dimension at response may result in a stimulus-response compatibility (SRC) effect as long as the color is represented in working memory. These studies have implications for the dimensional overlap model and the broader understanding of stimulus-response compatibility effects.