https://www.scientificamerican.com/article/students-who-gesture-during-learning-grasp-concepts-better/

When we talk, we naturally gesture—we open our palms, we point, we chop the air for emphasis. Such movement may be more than superfluous hand flapping. It helps communicate ideas to listeners and even appears to help speakers think and learn.

A growing field of psychological research is exploring the potential of having students or teachers gesture as pupils learn. Studies have shown that people remember material better when they make spontaneous gestures, watch a teacher’s movements or use their hands and arms to imitate the instructor. More recent work suggests that telling learners to move in specific ways can help them learn—even when they are unaware of why they are making the motions.