Identification of unfamiliar people from point-light biological motion: A perceptual reevaluation

Abstract

ABSTRACT Point-light displays (PLDs) depict humans in motion and support action perception. Previous studies indicate that biological motion provides identity cues for familiar, but not unfamiliar, people. We examined the role of biological motion for unfamiliar person identification using an identity-matching task (same or different person?) that did not involve a memory component. Participants viewed pairs of biological motion videos of unfamiliar people and rated their certainty of whether the pairs showed the same person or different people. Individuals in the pairs performed the same action (e.g., both walking) or different actions (e.g., walking and boxing). In the same-action condition, performance was well above chance (area under the ROC curve, a-ROC = .76, p < .0001). In the different-action condition, identification accuracy was lower, but still greater than chance (a-ROC = .55, p < .01). We conclude that biological motion cues support reliable perceptual discrimination of the identity of unfamiliar people.