visual illusions
mixingmemory | June 11, 2006As you all know, I love visual illusions, and this may be one of my favorites. This picture is pretty small (go here for a bigger version), but you should be able to figure out what's going on by watching it for a moment. Notice that as the face flips over, you briefly see the concave surface of the back or inside of the mask, but it quickly switches back to a convex, upside-down mask. That's not because the image changes, though. Instead, your brain decides that faces can't be hollow, so it changes it for you. This is called depth inversion, or the "hollow face illusion." Interestingly,…