Explaining Math: Gesturing Lightens the Load

TLDR

People tend to gesture while speaking because gesturing reduces cognitive load during speech. Participants recalled a list of items while explaining math solutions, comparing conditions with and without gesturing. Gesturing during math explanations improves memory recall by freeing cognitive resources, indicating that gestures both reflect and influence cognitive state.

Abstract

Why is it that people cannot keep their hands still when they talk? One reason may be that gesturing actually lightens cognitive load while a person is thinking of what to say. We asked adults and children to remember a list of letters or words while explaining how they solved a math problem. Both groups remembered significantly more items when they gestured during their math explanations than when they did not gesture. Gesturing appeared to save the speakers' cognitive resources on the explanation task, permitting the speakers to allocate more resources to the memory task. It is widely accepted that gesturing reflects a speaker's cognitive state, but our observations suggest that, by reducing cognitive load, gesturing may also play a role in shaping that state.