Playful behavior can help a species survive. Adult bonobos, for example, seem to make silly faces as a way of reducing tension with potential mates. Similarly, male polar bears sometimes fake-fight, which may help them to gauge the limits of their own strength before risking full-on brawls.
—Gordon Burghardt, professor of psychology and ecology at the University of Tennessee, Knoxville
Children have always liked animal figurines, dolls, and mini weapons and tools. But so-called object play is even older than humanity. Chimpanzee babies do it too. Like our own kids, they want to copy what they see adults doing so they can gradually master it.
—Michelle Langley, archaeologist at Griffith University
Make-believe can help little ones learn to manage and control their emotions. In the classic “marshmallow test,” preschoolers successfully…