BOB HIRSHON (host):
Tracing the laugh’s tracks. I’m Bob Hirshon and this is Science Update.
Where did laughter come from? That’s the focus of a recent scholarly paper by Matthew Gervais and David Sloan Wilson of Binghamton University. They trace its origin to a quiet panting seen in other primates, which may signal that it’s okay to relax and play. Gervais believes a key shift happened about four million years ago, when our ancestors started walking upright and exploring harsh new environments.
MATTHEW GERVAIS (Binghamton University):
And there would have been less time for play; at the same time play was probably more important, because of these stresses.
Luckily, walking upright also made it easier to vocalize. So over time, our laugh got louder, more recognizably human, and easier to hear in rare moments of calm.
I’m Bob Hirshon, for AAAS, the science society.