When I was in elementary school, the student newspaper had a little section of anonymous messages between students. The only time I got into it was when someone posted a note saying, “Alex! Your hand gestures are driving me crazy!”

I guess I did gesture a lot when I talked. I still do. I also tend, in the middle of involved conversations, to get up and pace, and draw things on the board. It’s what I do, and I’m sure it’s one reason that embodied cognition arguments feel correct to me.

Well, a team of German neuroscientists recently discovered “differences between people who gesture frequently and those who gesture rarely,” suggesting that “gesturing may be a function of, and may even contribute to, brain development.

Here’s the experiment.

In a recent investigation, we selected fifty-one 11th grade students at three Berlin high schools that specialized in mathematics and natural sciences. The students were given intelligence tests and assigned to one of the two groups, according to their scores. They were then asked to solve a visual analogy task in which they had to decide whether two chessboard-like patterns on the left side of a computer screen were mirrored on the same axis as two patterns on the right side of the screen.

Not surprisingly, students with high fluid intelligence – the type of intelligence that is responsible for abilities such as problem-solving, learning, and pattern recognition – performed better at this task than their peers with average fluid intelligence. Even more interesting, however, was that when describing how they solved the problem, the students with high fluid intelligence also gestured more. More specifically, they made gestures with their hands or fingers that simulated circular movements around an axis.

Surprisingly, all the students talked about the same things in their explanations, but almost no one actually mentioned anything about rotation. But by looking at their hands – not by listening to what they were saying – we could distinguish between people with high and average fluid intelligence. We think that these hand gestures mimicked the strategy that the students used in solving the task. That is, they rotated the patterns in their imagination, just as they did with their hands. This suggests that individuals with high fluid intelligence engage more in simulation when imagining the problem than those with average fluid intelligence.