Patterns of perceptual asymmetry in processing facial expression.

The paper reports four visual half-field experiments on the recognition of schematic faces whose emotional expression varied. Experiments I and II tested accuracy of recognition in a match-to-sample task. The results confirmed an overall left visual-field superiority in face recognition, but an analysis of a subset of the stimuli indicated that the direction and magnitude of the perceptual asymmetry depend upon the sign of the emotional expression. A replot of the results based on direct scaling of emotional expression (Experiment III) revealed an asymmetry gradient shifting from a left visual-field superiority for faces displaying hostile, aggressive emotions. When the stimuli are rotated 180 degrees the faces lose their emotional expression and no visual half-field asymmetry in recognition was observed in this condition (Experiment IV). It is concluded that emotional signals are processed independently of pattern, object and face recognition, and that the relative contribution of the left and right cerebral hemispheres to processing of emotional signals varies according to the type of emotion displayed.