When little kids are concentrating hard on some complicated task, you’ve likely noticed that they tend to stick their tongues out. (And some adults do this, too, though it’s markedly less endearing.) But why? A new study published in an August issue of the journal Cognition offers one theory. “This isn’t just a cute quirk of childhood, the findings suggest,” writes Christian Jarrett in a recent post for BPS Research Digest, “rather the behaviour fits the theory that spoken language originally evolved from gestures.”
A team of researchers from the U.K. and Sweden observed and videotaped 14 Swedish children, all 4 years old, completing a series of tasks that required concentration: one required fine motor control, such as playing on their own with a lock and key; another required communication, like playing with an experimenter a game they called “knock and tap.” (Basically, when the researcher knocked on a table, the kid was supposed to tap it with an open palm, and vice versa.) A third task tested story comprehension, and the children’s ability to recall details from a short tale the experimenter told them.
During each of these tasks, the kids stuck out their tongues now and then during the think-ier parts. This is in line with earlier research, which found that kids tend to do the tongue thing until about age 6. But the children stuck their tongues out most often during the knock-and-tap game. The finding was a surprise to the researchers, who expected the behavior would pop up most often when the kids were doing the fine-motor-control tasks. (Anyone who’s ever seen a little kid work on a puzzle would likely agree.) But, as Jarrett explains, what they actually found “makes sense in terms of the evolutionary history of language,” he writes. “[T]he knock and tap game involves rapid turn-taking, hand gesturing and structure rules—what you could think of as ‘the foundational components of a communication system’ or the rudiments of language.” What an adorable insight into the evolution of spoken communication.