Emotions in chimpanzee infants: The value of a comparative developmental approach to understand the evolutionary bases of emotion

This chapter examines the developmental processes in chimpanzees, to better understand species-specific characteristics not only of the chimpanzee, but also in humans. It discusses the evidence that chimpanzees share with humans many early behaviours. Chimpanzee infants, like human infants, exhibit some emotional expressions in the first days of life, and additional expressions develop over the first months of life. The chimpanzee emotional system, just like the human emotional system, develops in interaction with the social environment, as evident in the differential number of smiles, and different levels of crying during the first weeks of life.