How Cats Taught Us To Better Understand Optical Illusions

We’re all familiar with optical tricks like the Sander parallelogram or the vertical-horizontal illusion. But they don’t work for everybody. Why do these images fool some people and not others? It turns out, as PBS’s BrainCraft explains, that it’s all down to what you grew up with and experienced.

The cats come in due to a visual study where kittens were at first raised in the dark, and slowly exposed to light in a way that their brains could only see vertical or horizontal stripes. As the cats grew, and were introduced to environments with both kinds of lines, they had trouble distinguishing types they hadn’t been raised with.

Humans are a less extreme version of this; if you grow up in an environment with a lot of vertical lines like, say, a city, you’re going to have more trouble distinguishing horizontal lines, and vice versa. So, if you’re fooled by the optical illusions, don’t fret: It’s just how you’ve been raised.

(Via The Mary Sue)