Thursday, August 01, 2002

CHIMPANZEES, LIKE HUMANS, MORE EXPRESSIVE ON LEFT SIDE OF FACE

Lateral bias in chimpanzee expressions of facial emotion
19 July 2002
by Fiona Lyddy fiona.lyddy@may.ie
Fernandez-Carriba S et al. (2002). Asymmetry in facial expression of emotions by chimpanzees. Neuropsychologia, 40:1523-1533.

In humans, the left hemiface is generally found to be more emotionally expressive than the right, a finding consistent with innervation by the right cerebral hemisphere, which is dominant for emotional behaviour. Similar asymmetries documented in non-human primates suggest evolutionary precursors to brain laterality in emotional expression. A recent study by Fernandez-Carriba et al. examined facial expression of emotion in another highly social species with a rich repertoire of facial expressions, our close relative, the chimpanzee....

Both the objective and subjective measures indicated a greater involvement of the left hemiface in the production of facial expressions of emotion in chimpanzees, suggesting that chimpanzees, like humans, show a right hemisphere specialization for facial expression.