I have never learned sign language, but anyone who knows me knows that I wave my hands around when I talk. I always thought it was just part of my general inability to remain still for any longer than a few seconds, but apparently, there is a reason. I tend to speak out loud to focus my thoughts and these gestures help me with that process. I tend to get some really strange looks from the other side of the street. when I’m walking and talking to myself.
Gesture Changes Thought by Grounding It in Action Psychological Science November 2010 vol. 21 no. 11 1605-1610
When people talk, they gesture. We show that gesture introduces action information into speakers’ mental representations, which, in turn, affect subsequent performance. In Experiment 1, participants solved the Tower of Hanoi task (TOH1), explained (with gesture) how they solved it, and solved it again (TOH2). For all participants, the smallest disk in TOH1 was the lightest and could be lifted with one hand. For some participants (no-switch group), the disks in TOH2 were identical to those in TOH1. For others (switch group), the disk weights in TOH2 were reversed (so that the smallest disk was the heaviest and could not be lifted with one hand). The more the switch group’s gestures depicted moving the smallest disk one-handed, the worse they performed on TOH2. This was not true for the no-switch group, nor for the switch group in Experiment 2, who skipped the explanation step and did not gesture. Gesturing grounds people’s mental representations in action. When gestures are no longer compatible with the action constraints of a task, problem solving suffers.
The Tower of Hanoi is demonstrated in this video.
Explaining this puzzle to others verbally requires hand gestures, but those with differing gestures completed the puzzle the second time with various degrees of alacrity.
people who had spontaneously gestured with only one hand when asked to explain their solution, took longer to solve the puzzle the second time.
In comparison, those who had spontaneously used both hands, though, were quicker–presumably because they immediately used both hands on the now-heavy block.
What had happened was that how people had gestured while they explained the task had changed how they had remembered to complete it….
And, from the perspective of someone learning from another, people can learn certain tasks better when the other person gestures at them.
So that’s why I wave my hands around when I talk.
More context is given by Jeremy Dean, psychologist and author of PsyBlog.