Thanks to an effect called the hollow-mask illusion, the brain can have trouble deciding if the image is convex or concave. But, it seems, not everyone struggles to correctly determine the mask ...

“Sleepy Hollow” gives the Headless Horseman a shotgun ... He tries to hold off the Headless Horseman using his brain to control chains, but the Horseman cuts through them with his axe ...

viewers perceive a concave face (like the back side of a hollow mask) as a normal convex face. The illusion exploits our brain's strategy for making sense of the visual world: uniting what it ...

A scan of the skull of a 319-million-year-old fossilized fish has led to the discovery of the oldest example of a well-preserved vertebrate brain ... contained hollow spaces similar in appearance ...