Your Brain: The Missing Manual

Chapter 4. Perception

Your brain is a reality-construction machine. It takes the vast oceans of information that flood your senses, and transforms them into a highly subjective inner world.

This inner world has a few things in common with outside reality, but less than you'd think. It's run by a processing system that's quick to jump to conclusions, confidently ignorant of its mistakes, and easily fooled. This processing system sees what it expects to see, hears what it expects to hear, and petulantly refuses to be corrected on even the simplest point. You may enjoy this world or you may not. However, you'll never get a chance to step out of your head and take a clear look at what's really happening outside.

That's where this chapter fits in. Here, you'll explore some of the ways that the brain shapes outside reality. You'll learn about the quirks of the eyes, ears, and other senses, and the automatic assumptions that are deeply ingrained in your brain. Occasionally, this knowledge will help you "unfool" yourself—in other words, it lets you anticipate your brain's hiccups and work around them. Other times you'll learn enough to fool someone else, which is just as good (and makes a solid foundation for a career in politics, advertising, or real estate). Either way, this chapter gives you an opportunity to pull back the curtain and steal another quick look at the strange machine that runs your life.

The Doors of Perception

It's tempting to divide the brain's information processing into ...