How to See It Both Ways

When you see something, how do you figure out what it is? It might seem like you “just know”, but your brain uses two methods to help you know what you are seeing. One method is called bottom-up processing. In this method, the brain uses the shapes and colors seen by your eyes to figure out what something is. The other method is called top-down processing, which uses experiences, memories, or expectations to figure out what you are seeing. These processes happen at the same time in different parts of the brain. This article will explain how the brain’s top-down and bottom-up expectations can change what you see, and we include special pictures so you can experience it yourself.