Contrast polarity of eyes modulates gaze-cueing effect

Two experiments using a modified Posner-type visual cueing paradigm tested the prediction that detecting the darker region of the eyes of another's gaze triggers a reflexive orienting of the observer in the direction of the gaze. A target was presented in the left or right visual-field following a gaze-cue with positive or negative-image polarity (Experiment 1). In Experiment 2, the polarity of the eyes was manipulated independently of the negative polarity of the face (eye-positive or eye-negative-image polarity conditions). The results showed that the response to the target presented at the side the eyes gazed toward was faster than for the target presented at the other side in the positive polarity condition (Experiment 1), whereas, in the negative polarity condition, the gaze-cuing effect was not found. In Experiment 2, in the eye-negative condition, a reversed gaze-cueing effect appeared, whereas in the eye-positive polarity condition, a typical gaze-cueing effect was obtained. These findings suggested that the reflexive orienting of the observer shifts toward the position indicated by the darker region of the other's eyes.