Gesture handedness predicts asymmetry in the chimpanzee inferior frontal gyrus

Neuroanatomical asymmetries have been identified in chimpanzee frontal and temporal lobes including regions believed to be homologous to human Brocas and Wernicke's areas. This study examined whether or not neuroanatomical asymmetries in chimpanzees are associated with hand use during gestural communication. Analyses revealed that those chimpanzees that reliably employ their right hand for manual gestures have larger inferior frontal gyri in the left hemisphere than those apes that do not show consistent hand use for gestures. These findings are the first to provide a direct link between neuroanatomical asymmetries and the production of lateralized communicative behavior in non-human primates.