Facial expressions are potent social cues that can induce behavioral dispositions, such as approach-avoidance tendencies. We studied these tendencies by asking participants to make whole-body forward (approach) or backward (avoidance) steps on a force plate in response to the valence of social cues (happy or angry faces) under affect-congruent and incongruent mappings. Posturographic parameters of the steps related to automatic stimulus evaluation, step initiation (reaction time), and step execution were determined and analyzed as a function of stimulus valence and stimulus-response mapping. The main result was that participants needed more time to initiate a forward step towards an angry face than towards a smiling face (which is evidence of a congruency effect), but with backward steps, this difference failed to reach significance. We also found a reduction in spontaneous body sway prior to the step with the incongruent mapping. The results provide a crucial empirical link between theories of socially induced action tendencies and theories of postural control and suggest a motoric basis for socially guided motivated behavior. © 2011 The Author(s).
Stins, J. F., Roelofs, K., Villan, J., Kooijman, K., Hagenaars, M. A., & Beek, P. J. (2011). Walk to me when I smile, step back when I'm angry: emotional faces modulate whole-body approach-avoidance behaviors. Experimental Brain Research, 212(4), 603-611. https://doi.org/10.1007/s00221-011-2767-z