You see what you expect to see

Laurence Gonzales in Deep Survival. Page 69.

As complex as the brain is, the world is more so. The brain cannot process and organize all the data that arrive. It cannot come up with a reasonable course of action if everything is given equal weight and perceived at equal intensity. That is the difficulty with logic: It's step-by-step, linear. The world is not.

Perceptions come at you like the six million hits you get when you do an internet search. Without a powerful search engine, you're paralyzed. One search engine involves emotional bookmarks, in which feelings help direct logic and reason to a place where they can do useful work. A second strategy the brain uses for handling complicated problems is to create mental models, stripped-down schematics of the world. A mental model may tell you the rules by which an environment behaves or the color and shape of a familiar object.

Suppose you're searching the house for your copy of Moby-Dick, and you remember it being a red paperback but you don't know where you left it. When you search, you don't examine every item in the house to see if it's Moby-Dick. That would be logical, a strict use of the faculty of reason. But it would also be tedious and would take too long. That's how a computer would do it. The fact that you have a mental model of the red paperback copy of Moby-Dick, allows you to screen out nearly everything you see until, at last, a red book blossoms in your field of vision. But if you're wrong and it's a blue hardback edition of Moby-Dick, chances are that you won't find it even if the title comes into view.

Everyone is familiar with finding something "right under my nose." A faulty mental model is part of the explanation. It's the reason you can get off an elevator on the wrong floor. It's the reason that many card tricks and magic acts work: You see what you expect to see. You see what makes sense, and what makes sense is what matches the mental model. If you do suucceed in finding your copy of Moby-Dick, your pupils will dilate at the moment you recognize what you're looking for, as they do when you reach the solution to a mathematical problem or see something you like.