Where You Look Is What You Get: Individual Fixation Height Predicts Biases in Face Perception

Individuals show robust differences in where they look on a face. Some fixate closer to the eyes while others fixate closer to the mouth. While humans infer mental states and traits from specific facial regions and their expressions, such idiosyncratic gaze patterns may shape how individual features contribute to the overall impression of a face. We hypothesized that an individual's habitual fixation behavior biases their impression of a face to be aligned more closely with the region they most often foveate. To test this idea, we analyzed fixation patterns on faces in a scene viewing task and independent perceptual judgments regarding valence, arousal, trustworthiness, dominance, and attractiveness for whole faces and face parts. A linear mixed-effects model confirmed that habitual fixation proximity to eyes, nose, and mouth explained individual differences in how well ratings for whole faces were aligned with those for the corresponding isolated feature. Building on this finding, we ran a second experiment to test whether individual differences in face fixations can predict diverging impressions of trustworthiness in appropriately manipulated images. Observers reported which of two consecutively presented versions of a subtly manipulated face they perceived to be more trustworthy. Consistent with our hypothesis, individuals who tend to fixate lower down or higher up were weakly biased to prefer versions of the face with a more trustworthy bottom or top, respectively. Together, our findings indicate that individual differences in gaze can systematically bias our sometimes-diverging impression of a face.