Transmission of facial expressions of emotion co-evolved with their efficient decoding in the brain: behavioral and brain evidence

Schyns, P. G. , Petro, L. S. and Smith, M. L. (2009) Transmission of facial expressions of emotion co-evolved with their efficient decoding in the brain: behavioral and brain evidence. PLoS ONE, 4(5), e5625. (doi: 10.1371/journal.pone.0005625) (PMID:19462006) (PMCID:PMC2680487)

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Competent social organisms will read the social signals of their peers. In primates, the face has evolved to transmit the organism's internal emotional state. Adaptive action suggests that the brain of the receiver has co-evolved to efficiently decode expression signals. Here, we review and integrate the evidence for this hypothesis. With a computational approach, we co-examined facial expressions as signals for data transmission and the brain as receiver and decoder of these signals. First, we show in a model observer that facial expressions form a lowly correlated signal set. Second, using time-resolved EEG data, we show how the brain uses spatial frequency information impinging on the retina to decorrelate expression categories. Between 140 to 200 ms following stimulus onset, independently in the left and right hemispheres, an information processing mechanism starts locally with encoding the eye, irrespective of expression, followed by a zooming out to processing the entire face, followed by a zooming back in to diagnostic features (e.g. the opened eyes in "fear", the mouth in "happy"). A model categorizer demonstrates that at 200 ms, the left and right brain have represented enough information to predict behavioral categorization performance.

Item Type:Articles
Additional Information:This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Glasgow Author(s) Enlighten ID:Petro, Dr Lucy and Schyns, Professor Philippe and Smith, Dr Marie
Authors: Schyns, P. G., Petro, L. S., and Smith, M. L.
College/School:College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
College of Science and Engineering > School of Psychology
Journal Name:PLoS ONE
Publisher:Public Library of Science
ISSN (Online):1932-6203
Copyright Holders:Copyright © 2009 Schyns et al
First Published:First published in PLoS ONE 2009 4(5): e5625
Publisher Policy:Reproduced under a Creative Commons License

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