Context-Dependent Gestural Laterality: A Multifactorial Analysis in Captive Red-Capped Mangabeys

Area of Science:

• Primate communication
• Animal behavior
• Neuroscience

Background:

• Human language lateralization may stem from primate gestural origins.
• Factors influencing gestural laterality in non-hominoid primates are understudied.
• Intraspecific gestural laterality offers insights into language evolution.

Purpose of the Study:

• Investigate intraspecific gestural laterality in red-capped mangabeys (Cercocebus torquatus).
• Examine factors influencing gestural laterality in a non-hominoid primate.
• Explore the relationship between gestural communication and brain lateralization.

Main Methods:

• Observation of spontaneous brachio-manual intentional gestures in 25 captive red-capped mangabeys.
• Analysis of gestural laterality in relation to social context, receiver position, gesture form, and socio-demographic factors.

Main Results:

• No significant individual or population-level gestural lateralization was found.
• Mangabeys preferentially used their right hands for gestures in negative social contexts (e.g., aggression).
• Subjects adapted gestural laterality by using the ipsilateral hand to communicate with a receiver.

Conclusions:

• Emotional context and receiver proximity influence gestural laterality in mangabeys.
• Findings align with previous ape studies, suggesting shared mechanisms.
• A multifactorial approach is recommended for studying primate gestural communication and brain lateralization.