System 1 and System 2 (Automatic and Reflective Thinking)

How We Think: Two Systems

It goes without saying that the biases we have described in this chapter do not apply to everyone the same way. Yes, most people are overconfident and optimistic—but not everyone. In fact we have a good friend who has the opposite traits—he is never confident and is always worried about something, or many things. That friend happens to be Daniel Kahneman, with whom we have both had the privilege of being coauthors. A draft of a paper or book chapter that seemed good last week suddenly can look terrible to him this week. He is constantly rethinking everything. And this is particularly true of his own work.

This trait led him to take an unusual step when he won the Nobel Memorial Prize in Economic Sciences in 2002. Laureates are asked to deliver a lecture during their week in Stockholm. Most choose to discuss the work that earned the prize in a manner accessible to a lay audience. Kahneman did that, but in his own, unique way. He presented an entirely new way of looking at his joint work with Amos Tversky (who would have shared the prize had he been alive), using a concept from cognitive psychology that had not played even the slightest role in creating the research. Only Kahneman would take the already frantic two months between the announcement of the prize and the ceremony to rethink his life’s work completely. This rethinking was later refined and expanded in his bestselling book Thinking, Fast and Slow.

The title of the book cleverly states the main idea, to which we devote the rest of this chapter. It is useful to imagine the workings of the brain as consisting of two components or systems. One is fast and intuitive; the other is slow and reflective. Kahneman adopts the terminology of the psychology literature on which he draws, and calls these two components System 1 and System 2. One of us had trouble remembering which one is the fast one (it is 1), so we prefer to use names that remind the reader what they are. We call them the Automatic System and the Reflective System.

Using this framework can help us understand a puzzle about human thought. How can we be so ingenious at some tasks and so clueless at others? Beethoven wrote his incredible Ninth Symphony after he had become deaf, an amazing feat, but one would be hardly surprised to learn that he often misplaced his house keys. Was he a genius or an imbecile? The answer is some of both.

The work of psychologists and neuroscientists on whose work Kahneman relied converged on a description of the brain’s functioning that helps us make sense of these seeming contradictions. The approach involves a distinction between two kinds of thinking.17

Two Cognitive Systems: