Abstract
Previous studies of walking gait have reported counter-intuitive self-recognition effects whereby actors are able to better identify allocentric displays of their own walking gait, than those of friends. Insofar as actors typically have little visual experience of their own gaits from third-person perspectives, such effects may indicate a contribution to perception from the motor system. Here we sought to determine whether participants showed a similar self-recognition effect when asked to identify facial motion derived from themselves, friends or strangers. Motion was isolated from form cues using a markerless image processing technique, and used to animate an average head avatar. A single avatar stimulus was presented on each trial and participants were required to respond self, friend or other. Participants first completed a block of upright trials and then completed a second block with stimulus orientation inverted. Some evidence of superior self-recognition was found, in that stimuli were correctly identified more often when viewed by the actor from which they were derived, than when viewed by friends or strangers. However, the self-recognition effect observed was primarily attributable to performance in the inverted condition. Whereas orientation inversion drastically impaired friends' ability to recognise an actor, inversion had no effect on the ability of actors to recognise themselves. These findings suggest that recognition of self-produced and friends' motion may be mediated by different cues. Since recognition of friends' motion is sensitive to orientation, friend recognition may require the perception of configural, correlated motion cues derived from across the whole face. In contrast, self-recognition may rely on local motion cues extracted from particular features, and thus be insensitive to inversion. An observer's motor system may also serve to enhance recognition through the representation of the rhythmic or temporal characteristics of local motion cues.