In the new Journal of Neuroscience, Barrow Neurological Institute researchers present their study exploring why Akiyoshi Kitaoka's "Rotating Snakes" optical illusion is so effective. In fact, it's the cover story! From Science News:
Participants held down a button when the snakes seemed to swirl and lifted the button when the snakes appeared still. Right before the snakes started to move, participants began blinking more and making short jumpy eye movements called microsaccades, Jorge Otero-Millan, Stephen Macknik and Susana Martinez-Conde report in the April 25 Journal of Neuroscience. When volunteers' rates of microsaccades slowed down, the visual illusion faded and the snakes were more likely to stop moving.
"Snakes swirl in blink (and jump) of an eye" (Science News)
Abstract: "Microsaccades and Blinks Trigger Illusory Rotation in the "Rotating Snakes" Illusion" (Journal of Neuroscience)