Your Brain Can’t Map Altitude

If you've ever flown, you know that the captain will usually announce your cruising altitude over the intercom at some time. Perhaps you've never given it much attention, but the next time you're up there, see if you can determine your altitude before being told. Because our brains are terrible at mapping altitude, there's a good chance you can't.

The area of rats' brains that maps space and distance barely registers when the animal is only moving upward, according to research on the brains of rats as they ascended. Because our brains appear to interpret how things work in three dimensions, particularly being able to travel up vertically, differently than it understands working on the ground, the cells that measure distance simply do not know how far up an animal goes when it is climbing. It's similar to using two different maps to get around. The vertical one is harder for your brain to read than the horizontal one.