We've Been Laughing Like Apes for Millions of Years

Humans didn't invent the chuckle so much as refine it, suggests new research out of the University of Warwick. In recordings of 17 great apes and four people—from orangutans to gorillas—researchers analyzed 140 bouts of laughter and found they all followed the same steady beat: evenly spaced bursts of sound, per Phys.org. That shared rhythm implies it arose in a common ancestor at least 15 million years ago, according to the study in Communications Biology. What changed over time, scientists say, is how tightly humans learned to steer that rhythm. Our laughs are faster, more varied, and more tied to context—think genuine giggle versus polite office chuckle or nervous titter.

That ability to control timing and style may be one of the building blocks that later enabled speech. "We've found a 15-million-year-old clue in an unexpected place: our laughter," says lead author Chiara De Gregorio of the University of Warwick in England, who argues that rather than a sudden leap, human language likely emerged from vocal control that apes had been gradually sharpening for millions of years. If you're wondering how the scientists got the primates to laugh, the answer is simple: They tickled them, per the AP.