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Published on: November 16, 2017
Right hemisphere dominance for emotion processing in baboons.
Catherine Wallez1, Jacques Vauclair
1University of Provence, Center of Research in the Psychology of Cognition, Language & Emotion, Department of Psychology, 29 Ave. Robert Schuman, 13621 Aix-en-Provence Cedex 1, France.
Brain and Cognition
|December 7, 2010
Summary
Olive baboons show a left-sided facial asymmetry during screeching, suggesting emotional expression lateralization. This finding supports the evolution of human brain specialization for emotions in primates.
Area of Science:
- Neuroscience
- Ethology
- Primatology
Background:
- Emotional facial expressions in humans indicate brain lateralization, often showing right hemisphere dominance.
- Previous studies on nonhuman primates (chimpanzees, marmosets, macaques) largely reported left-sided oro-facial asymmetries.
Purpose of the Study:
- To investigate functional cerebral asymmetries in Olive baboons through oro-facial productions.
- To determine if emotional facial expressions in baboons exhibit lateralization.
Main Methods:
- Recorded two affiliative behaviors (lipsmack, copulation call) and two agonistic behaviors (screeching, eyebrow-raising) in Olive baboons.
- Assessed the presence and direction of asymmetrical oro-facial productions during these behaviors.
Main Results:
- A significant left hemimouth bias was observed specifically for screeching (an agonistic behavior).
- No significant facial asymmetry was found for lipsmack, copulation call, or eyebrow-raising.
Conclusions:
- The findings suggest that emotional facial asymmetry, particularly in agonistic contexts, may be present in Olive baboons.
- These results contribute to understanding the evolutionary precursors of human hemispheric specialization for emotional processing.
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