Even a Second of Laughter Speaks Volumes

What can be revealed in just a brief moment of laughter—an audio recording a mere second long, played without any context to people in two dozen different parts of the world? Quite a lot, it turns out. In fact, that tiny blip of sound is enough for many of us to correctly guess whether the two people laughing are friends or strangers, report UCLA scientists in the Proceedings of the National Academy of Sciences. In an unusually large study on laughter, they played the short recordings to 966 individuals ranging from Tanzania's Hadza people to rural Peruvians to university-educated Europeans and Egyptians. "With laughter you're looking at a human universal," one neurologist not involved in the study tells the Smithsonian, which has posted a sample quiz of six recordings of laughter on SoundCloud.

While the total number of correct guesses isn't much above a coin toss at 61%, the trends were surprisingly consistent across cultures, reports NPR. Some highlights: People were correct as much as 80% of the time when the people laughing were both women and close friends. And perhaps because those laughing were American, the best guessers hail from the US, where listeners correctly identified those laughing as friends 95% of the time. The lowest results were when people around the world listened to female strangers—participants guessed correctly less than half the time. Either way, being able to "read" laughter may be an evolutionary imperative to social well-being; as one researcher notes, "When you're alone, laughter basically disappears." (Think you're getting away with that fake laugh among friends? Think again.)