Why do we move our hands when we talk II: Learning new concepts

In the last post, I talked about some of the roles that gestures play in communication, and I focused on how moving your hands can help you remember the word you want to use. Another important aspect of gestures is that they are connected to our ability to think about and manipulate space. As a result, our ability to make gestures may help us to learn new concepts that originate with spatial knowledge.

In one set of studies (published in the journal Cognitive Science in 1996), Dan Schwartz and John Black had people learn about the motion of gears. They had people solve problems involving different numbers of gears. One set of problems involved determining what direction the last gear in a chain of gears would turn if the first gear moved in a particular direction (either clockwise or counterclockwise). More complex problems looked at loops made of gears.

If you have never tried problems like this before, take a moment. Draw out a string of five gears. If the first gear moves clockwise, what direction does the fifth gear go?

To make things more complicated now, try a ring of 7 gears. If you turn one gear in a clockwise direction, what happens?

There are two ways to solve problems like this. One possibility is that you already know the answer. For chains of gears, there is a simple answer. Count the gears. Every even-numbered gear moves in the same direction, as does every odd-numbered gear. For rings, things are more complicated. If there is an even number of gears in the ring, then each gear moves in the direction opposite the one next to it, and all is well. If there is an odd number of gears, then two of the gears will try to move in the same direction, and the ring will actually lock and nothing will move at all.

How do people learn this rule? Schwartz and Black found that when people first started reasoning through these problems, they made a lot of hand motions. Often, they would curl their fingers and move them, noticing that the hands would move in opposite direction, So, people were able to use gestures to simulate a spatial situation, and then could observe that spatial situation to form a rule that would help them solve future problems.

Susan Goldin-Meadow, Susan Wagner Cook, and Zachary Mitchell have another nice demonstration of the way gestures can be used to learn in a paper published in the March, 2009 issue of Psychological Science. They taught 3rd and 4th grade children to solve math problems like

6 + 3 + 4 = ___ + 4

in which two numbers on one side of the problem had to be added together to make one number on the other side. Groups of children were given math lessons to learn to solve these problems. I'll talk about two of those groups for now. Both groups were taught to take the two numbers from the left-side of the equation that had to be combined, and to add them together and place the answer on the right-side. One group was taught without having the children use any consistent hand gestures. The other group was taught to make a V with their fingers under the first two numbers in the problem and then to point to the blank with one finger. So, this gesture reinforced the idea of taking the two numbers and combining them into one. The group given the consistent hand gestures was over twice as likely to solve later test problems than the group given no gestures. The researchers also analyzed the speech of children who solved these problems while talking aloud. They found that the hand gestures made it easier for children to describe their solution as grouping the two numbers together and adding them to form one number.

What is going on here?

Complex concepts like the motion of gears and the grouping of numbers in math can be difficult to think about abstractly. We are able to use our understanding of space to reason about these situations. However, trying to reason about space in our heads is difficult. Moving our limbs through space, though, is easy. So we ease the cognitive burden of these tasks by using gestures to keep track of the spatial aspects of the situation. We can then look at our own hand gestures for guidance in forming more complex ways of thinking about a situation.

These studies are good examples of the deep connection between body and mind. We might be tempted to think about math as the crowning achievement of people's ability to think abstractly. And yet, our ability to move our limbs in space makes it easier for us to learn math concepts.