Eye gaze is not unique: The reversed congruency effect on gaze and tongue targets

In the spatial Stroop task, an arrow target produces a spatial Stroop effect, whereas a gaze target elicits a reversed congruency effect. The reversed congruency effect has been explained by the unique attentional mechanisms of eye gaze. However, recent studies have shown that not only gaze but arrow targets produced a reversed congruency effect when embedded in a complex background. The present study investigated whether non-gaze targets produce a reversed congruency effect. In Experiments 1 and 2, we used the tongue, which is not commonly used to indicate spatial directions in daily life, as a target in the spatial Stroop task, in addition to the conventional gaze and arrows. In Experiment 3, we used arrow stimuli embedded in a complex background as a target. Participants judged the left/right direction of the target presented in the left or right visual field. Although arrow and gaze targets replicated previous findings (spatial Stroop and reversed congruency effect, respectively), the tongue target produced a reversed congruency effect (Experiments 1 and 2). The spatial Stroop effect of arrow targets disappeared when they were in a complex background (Experiment 3). These results are inconsistent with previous accounts emphasising the unique status of eye gaze. We propose that temporal decay of the location code and response inhibition are responsible for the reversal of spatial interference.