Apes, language, and the brain

Language is a unique form of communication in humans and is unmatched in the animal kingdom. There are well-defined cortical regions involved in both the comprehension and production of speech including Wernicke's and Broca's area. To what extent these regions play a role in the communicative abilities of primates, notably great apes, remains a central topic of research in neuroscience, anthropology, and psychology. In this chapter, I present an overview of the cognitive foundations of gestural and vocal communication in chimpanzees, including some results from language-trained apes. I also present data on the evolution in size and lateralization of Wernicke's and Broca's area in chimpanzees. These anatomical data are combined with behavioral data to show how individual differences in gestural and vocal communication are associated with volumetric and lateralized differences in Broca's and Wernicke's areas. The collective findings are discussed within the context of language evolution and the emergence of complex motor and cognitive processes in humans after the split from the common ancestor with chimpanzees.