Anger and happiness are linked differently to the explicit detection of biological motion

The detection of biological motion and the detection of emotion from this motion are important visual functions with obvious survival and social values. The perception of biological motion is remarkably robust, and numerous studies have shown that the emotional states of a person can be deduced from point-light biological motion. In the present study, we investigated the extent to which the detection of emotion from biological motion is linked to the explicit detection of human gait. Subjects performed gait detection and emotion detection for the same stimulus. The stimulus consisted of one coherent interval and one scrambled biological-motion interval, each of which contained one emotionally neutral and one emotional (angry or happy) walker. Significant correlations with gait detection performance were observed for anger detection but not necessarily for happiness detection, implying that the detection of anger may be more strongly linked to explicit gait detection. This leads to a hypothesis that differential dependence may reflect the differential behavioural meaning between anger and happiness detection; it may be more crucial to localise or identify a person with anger than happiness.