Seeing and Understanding Epistemic Actions

This webpage contains stimuli and demonstrations supporting:

Croom, S., Zhou, H., & Firestone, C. (2023). Seeing and understanding epistemic actions.
Proceedings of the National Academy of Sciences, 120, e2303162120.

Which video shows someone shaking for shape and which shows someone shaking for number?

Below, you will find links to the experiments we performed:

Questions? E-mail Sholei Croom ( or Chaz Firestone ( You can also visit the homepage of the JHU Perception and Mind Laboratory.