Social embodiment in directional stepping behavior.

Embodiment theories emphasize the role played by sensory and motor processes in psychological states, such as social information processing. Motivated by this idea, we examined how whole-body postural behaviors couple to social affective cues, viz., pictures of smiling and angry faces. We adopted a Simon-like paradigm, whereby healthy female volunteers were asked to select and initiate a forward or backward step on a force plate in response to the gender of the poser (male/female), regardless of emotion. Detailed analysis of the spatiotemporal unfolding of the body center of pressure during the steps revealed that task-irrelevant emotion had no effect on the initiation times of the steps, i.e., there was no evidence of an affective Simon effect. An unexpected finding was that steps were initiated relatively slow in response to female angry faces. This Stroop-like effect suggests that postural behavior is influenced by whether certain stimulus features match or mismatch.