Encouraging children to gesture when they are working on maths problems helps them benefit more from subsequent maths tuition. Sara Broaders and colleagues, who made the observation, say this is because gesturing activates children's implicit maths knowledge, which they are not yet able to consciously access or talk about.
In an initial study, 106 children aged nine to ten years were asked to solve problems like 6 + 3 + 7= ? + 7 and talk through their solutions. Later on, some of the children were also told that they must use their hands when explaining their answers. All the children got the maths problems wrong, but the hand movements of the children told to gesture revealed they had insight into new, often appropriate strategies, which they hadn't previously spoken of.
For example, the researchers said a sweeping movement of a child's palm, first under the left, then under the right side of the problem revealed that they understood both sides of the equation needed to be the same.
A second study with 70 children showed that the activation of this implicit knowledge in gesture has actual practical benefits. Again the children were presented with maths problems and asked to explain their answers; again some were told they must gesture when explaining, while others were told not to gesture. As before, the children told to gesture revealed novel strategies in their hand movements, even though they continued to get the answers wrong. Next, the children received some tuition in how to solve the problems. Critically, in a final test, the children previously told to gesture solved an average of 1.5 more problems correctly than the kids told not to gesture - in other words they seemed to have benefited more from the tuition.
The researchers concluded that being told to gesture reveals "previously unexpressed implicit knowledge that, in turn, makes learning more likely".
Broaders, S.C., Cook, S.W., Mitchell, Z. & Goldin-Meadow, S. (2007). Making children gesture brings out implicit knowledge and leads to learning. Journal of Experimental Psychology: General, 136, 539-550.