iStock/René Mansi

Go into any busy coffee shop and you are likely to see people engrossed in conversation, waving their hands around. A man at the counter describes the coffee he wants to buy – in a mug, not a to-go cup – and his hand takes a familiar shape, as if he were already holding the cozy mug. Nearby, two sisters laugh, as one tells a story about a trip to the barrier reef and all of the fish that she saw, her hands wiggling and darting in an invisible sea in front of her. The drive to gesture when speaking is fundamental to human nature.

If you have thought about why we gesture you probably assumed that we gesture to help others understand what we are saying. Pretending to hold a ceramic mug can help the barista understand exactly which mug you want. Showing how the fish darted to and fro can help your sister get a more vivid picture of what the reef looked like to you.

But might gesture also serve another purpose? Many scientists now think that gestures can help the person making them -- that moving your hands can help you think. Researchers have become increasingly interested in the connection between the body and thought – in the ways that our physical body shapes abstract mental processes. Gesture is at the center of this discussion. Now the debate is moving into learning, with new research on how students learn to solve math problems in the classroom.

To understand the research, consider a math problem like 3+2 +8 =___+8. A student might make a “v” shape under the 2 and 3 with their pointer finger and middle finger, as they try to understand the concept of “grouping” – adding adjacent numbers together, a technique that can be used to solve the problem. Previous research has shown that students who are asked to gesture while talking about math problems are better at learning how to do them. This is true whether the students are told what gestures to make, or whether the gestures are spontaneous.

Now researchers are asking how. The new study -- by Dr. Susan Goldin-Meadow and Zachary Mitchell of the University of Chicago, and Dr. Susan Wagner-Cook of the University of Iowa – focused on third and fourth graders solving a problem that required grouping. Students who are coached to make the “v” gesture when solving a math problem like 3+2+8 = ___+8 learn how to solve the problem better. But students also do a better job even if they were coached to make the “v” shape under the wrong pair of numbers. The very act of making the “v” shape introduces the concept of “grouping” to the student, through the body itself.

But what, exactly, was the process that made this possible? During the study, all of the students memorized the sentence “I want to make one side equal to the other side.” They were then asked to say the sentence out loud when they were give a problem to solve. The authors suggest that students who also gestured attempted to make sense of both the speech and gesture in a way that brought the two meanings together. This process, they suggest, could crystallize the new concept of “grouping” in the student’s mind.

The same process could occur in any situation where the person who is speaking and gesturing is also trying to understand – be it remembering details of a past event, or figuring out how to put together an Ikea shelf.