Humans Have an Expectation That Gaze Is Directed Toward Them

Summary Many animals use cues from another animal’s gaze to help distinguish friend from foe [1–3]. In humans, the direction of someone’s gaze provides insight into their focus of interest and state of mind [4] and there is increasing evidence linking abnormal gaze behaviors to clinical conditions such as schizophrenia and autism [5–11]. This fundamental role of another’s gaze is buoyed by the discovery of specific brain areas dedicated to encoding directions of gaze in faces [12–14]. Surprisingly, however, very little is known about how others’ direction of gaze is interpreted. Here we apply a Bayesian framework that has been successfully applied to sensory and motor domains [15–19] to show that humans have a prior expectation that other people’s gaze is directed toward them. This expectation dominates perception when there is high uncertainty, such as at night or when the other person is wearing sunglasses. We presented participants with synthetic faces viewed under high and low levels of uncertainty and manipulated the faces by adding noise to the eyes. Then, we asked the participants to judge relative gaze directions. We found that all participants systematically perceived the noisy gaze as being directed more toward them. This suggests that the adult nervous system internally represents a prior for gaze and highlights the importance of experience in developing our interpretation of another’s gaze.