Lateral asymmetry of bodily emotion expression

Summary Emotional behaviours in humans and animals, such as kissing or tail wagging, sometimes show characteristic lateral asymmetries [1,2]. 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 [3]. While this result has been interpreted as support for a right-hemisphere dominance in emotion expression [4], substantial ipsilateral innervation of the relevant facial musculature [5] and findings of reduced or reversed asymmetry for positive emotions [3,6] complicate the conclusion. It is therefore critical to investigate lateral asymmetries in emotion expression using effectors with clearly contralateral innervation. We report here a pronounced lateral asymmetry for emotional full-body movements [7], the left body side moving with higher amplitude and energy, and causing higher perceived emotional expressiveness of the left body side compared to the right. This finding provides strong support for a right-hemisphere dominance in the control of emotional expressions independent of the specific effector.