Different effects of smooth pursuit eye movements on motion-based stimulus response congruency

In motion-based stimulus response correspondence (SRC) effect responses are faster when the task irrelevant stimulus motion is congruent with the response movement performance. In the present study, we tested if smooth pursuit type eye movements related to the tracking of a moving object influence motion-based SRC when present on its own or when it was combined with position-based SRC. We looked at the motion-based SRC effect in the response selection and response execution stages. When investigating motion-based SRC alone, participants responded with left or right hand movements of the single hand to the left or right movements of the centrally presented stimulus either with their eyes fixated in the center either with their eyes tracking the moving object. In the case of motion-based SRC and position-based congruency participants responded with left or right movements of the left or right hand to the stimulus motion that was presented on the left or right side of the screen, again with eyes fixated in the center or with the eyes following moving target. Results showed that in the response selection stage, smooth pursuit type eye movements reduced the motion-based SRC when stimulus moved in the center, whereas it was enhanced when stimulus presentation was lateralized. This is in line with the idea that cognitive system computes various spatial maps for different cognitive purposes. In the case of response execution, smooth pursuit type eye movements always enhanced the motion-based SRC, what is consistent with the notion of eye and hand movements coupling during tracking.