This is a great animation from TED-Ed that shows what is going on inside your brain when optical illusions trick you.
What's fascinating about optical illusions is that they can affect different people in different ways. Some will work, some won't and some people will see different things in them. It may have something to do with how much we focus on them with single-minded concentration. When I post optical illusions over on my other site, the feedback I get often is completely at odds with my own experience with them.
For example, the Abe Lincoln illusion in this video did not trick me at all. But the muffin pan one - yup. Got me on that one.
This is another great science animation from TED -ED, which is a great addition to the animation field. For anyone interested, they use Adobe After Effects for compositing, and Dragonframe for stop-motion animation.
From the youtube page:
Optical illusions are images that seem to trick our minds into seeing something different from what they actually are. But how do they work? Nathan S. Jacobs walks us through a few common optical illusions and explains what these tricks of the eye can tell us about how our brains assemble visual information into the 3D world we see around us.
Lesson by Nathan S. Jacobs, animation by TED-Ed.