For decades, social scientists had used a mythical figure to describe how humans make decisions: homo economicus. He was logical and conscientious. To make a decision, he would evaluate all the options open to him, then choose the most rational course of action. Of course, this character wasn't representative of real human behavior, but no one had come up with a better model to explain how humans make decisions. Then along came Amos Tversky and Daniel Kahneman. In Judgment under Uncertainty, they explained exactly how the brain really processes information at a subconscious level, profoundly affecting our decision-making without us even being aware of it.