From UChicago News:

Children who use their hands to gesture during a math lesson gain a deep understanding of the problems they are taught, according to new research from The University of Chicago’s Department of Psychology. Previous research has found that gestures can help children learn. This study in particular was designed to answer whether abstract gesture can support generalization beyond a particular problem and whether abstract gesture is a more effective teaching tool than concrete action. The study found that abstract gesture was most effective in encouraging learners to generalize the knowledge they had gained during instruction. Action was least effective in encouraging generalization and concrete gesture was somewhere in between.