Gazing into space: Systematic biases in determining another's fixation distance from gaze vergence in upright and inverted faces.

The eyes of others play a crucial role in social interactions, providing information such as the focus of another's attention and their current thoughts and emotions. Although much research has focused on understanding how we perceive gaze direction, little has been done on gaze vergence, which can potentially yield information about the distance of another's fixation. Here, we presented participants with synthetic faces in a stereoscopically simulated 3-D environment to determine the absolute fixation distance at which they perceived a face to be gazing. The results showed an underestimation in fixation distance for downward-averted gaze and a limit in discrimination of gaze vergence beyond 35 cm. For inverted faces, fixation distance for gaze vergence in the lower visual field (corresponding to the avatar's upwards gaze) was underestimated, suggesting that our bias to underestimate others' fixation distance may rely on a viewer-centered, egocentric representation of interpersonal space.

Biases in perceiving gaze vergence.

The focus of another person's gaze is an important cue in social interactions, helping us to understand others' intentions, predict their behavior, and allocate our own attention appropriately. The perception of gaze vergence provides information about the distance at which another person is fixating, but has yet to receive much empirical attention. Here, we report that observers display systematic biases when perceiving others' gaze vergence and depth of fixation. Specifically, they perceive others as having convergent gaze and fixating at closer distances, especially when gaze is directed downward or observed under conditions of sensory uncertainty. These biases may reflect the predominance of convergent over divergent gaze in everyday social interactions and implicit knowledge of the physical structure of the environment, in which objects below our line of sight are typically closer. These findings demonstrate the sophistication of social vision, in which our visual perception of others is shaped by statistical regularities, and help to establish the perception of others' gaze vergence and fixation distance as a subject of psychological investigation. (PsycINFO Database Record