Why does the gaze of others direct visual attention?

Viewing another person directing his or her gaze can produce automatic shifts of covert visual attention in the same direction. This holds true even when the task-relevant target is much more likely to occur at the uncued location. These findings, along with other evidence, have been taken to suggest that gaze represents a "special" stimulus--the foundation of a social cognition system that can make inferences about the mental states of other people. However, gaze-driven cueing effects could simply be due to spatial compatibility between cue and target. We compared the attentional effects of gaze shifts to a face with the tongue extended laterally to the left or right. When tongue direction was a nonpredictive cue, we found cueing effects from tongues that were indistinguishable from those produced by gaze. However, in contrast to previous findings with gaze, tongue cues did not overcome a validity manipulation in which targets were four times more likely to appear at the uncued location. We conclude that simple attentional cueing effects from gaze may be better explained by spatial compatibility, and that more complex, unique features of cueing from gaze may be better indices into perceptual systems specialized for social cognition.