Emotional behaviours in humans and animals, such as kissing or tail wagging, sometimes show characteristic lateral asymmetries. Such asymmetries suggest differences in the involvement of the cerebral hemispheres in the expression of emotion.
An established example is the expressiveness advantage of the left hemiface that has been demonstrated with chimeric face stimuli, static pictures of emotional expressions with one side of the face replaced by the mirror image of the other. While this result has been interpreted
as support for a right-hemisphere dominance in emotion expression, substantial ipsilateral innervation of the relevant facial musculature and findings of reduced or reversed asymmetry for positive emotions and complicate the conclusion. It is therefore critical to investigate
lateral asymmetries in emotion expression using effectors with clearly contralateral innervation. We investigated motor asymmetries in emotionally expressive walking and tested whether such asymmetries lead to differences in the perceived emotional expressiveness of the movements of the left and the right body side.

Human observers readily recognise emotions expressed in body movement. Their perceptual judgments are based on simple movement features, such as overall speed, but also on more intricate posture and dynamic cues. The systematic analysis of such features is complicated due to the difficulty of considering the large number of potentially relevant kinematic and dynamic parameters. Applying sparse regression, we extracted critical emotion-specific posture and movement features, which typically depended only on a small number of joints. The features we extracted from the motor behaviour closely resembled features that were critical for the perception of emotion from gait.