Are eyes special? Gaze, but not pointing gestures, elicits a reversed congruency effect in a spatial Stroop task.

Abstract

Gaze stimuli can shape attention in a peculiar way as compared to non-social stimuli. For instance, in a spatial Stroop task, gaze stimuli elicit a reversed congruency effect (i.e., faster responses on incongruent than on congruent trials) as compared to arrows, for which a standard congruency effect emerges. Here, we tested whether the reversed congruency effect observed for gaze can emerge for other social signals such as pointing gestures. Participants discriminated the direction (left or right) indicated by gaze and pointing finger stimuli that appeared leftwards or rightwards with respect to a central fixation spot. Arrows were also employed as control non-social stimuli. A reversed congruency effect emerged for the gaze, whereas a standard congruency effect emerged for both the pointing finger and the arrows. This suggests that the reversed congruency effect is specific to gaze stimuli and does not embrace all social signals conveying spatial information.