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Human (Homo sapiens) and baboon (Papio papio) chimeric face processing: right-hemisphere involvement
Catherine Wallez1, Jacques Vauclair
1Department of Psychology, Research Center in the Psychology of Cognition, Language and Emotion, Aix-Marseille University, Aix-en-Provence, France. catherine.wallez@univ-amu.fr
Olive baboons show right-hemisphere specialization for screeching, but not eyebrow-raising. Human judges perceived greater emotional intensity in left-sided baboon facial expressions, suggesting shared emotional processing mechanisms.
Area of Science:
- Comparative Psychology
- Neuroscience
- Primatology
Background:
- Facial expressions are key to understanding emotional hemispheric specialization in humans and nonhuman primates.
- Orofacial asymmetries in Olive baboons offer insights into primate emotional communication.
Purpose of the Study:
- To investigate orofacial asymmetries in Olive baboons using objective and subjective measures.
- To explore hemispheric lateralization for emotional perception in humans using chimeric faces.
Main Methods:
- Objective assessment of hemimouth length and area for specific baboon facial expressions (screeching, eyebrow-raising).
- Subjective evaluation of baboon chimeric faces' emotional intensity by human judges.
- Chimeric face task with human faces to assess human judges' emotional processing lateralization.
Main Results:
- Right-hemisphere specialization was identified for screeching in Olive baboons.
- Left-composite chimeric faces of baboons and humans were perceived as more emotionally intense.
- Humans with left-hemisphere specialization for emotion processing better distinguished baboon emotional signals.
Conclusions:
- Findings suggest potential shared mechanisms for emotional facial expression processing between humans and Olive baboons.
- Results contribute to the understanding of hemispheric specialization in primate emotional communication.
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