Mind: Who You Are

Before Kahneman and Tversky, people who thought about social problems and human behavior tended to assume that we are mostly rational agents. They assumed that people have control over the most important parts of their own thinking. They assumed that people are basically sensible utility-maximizers and that when they depart from reason it's because some passion like fear or love has distorted their judgment.

Kahneman and Tversky conducted experiments. They proved that actual human behavior often deviates from the old models and that the flaws are not just in the passions but in the machinery of cognition. They demonstrated that people rely on unconscious biases and rules of thumb to navigate the world, for good and ill. Many of these biases have become famous: priming, framing, loss-aversion.

Kahneman reports on some delightful recent illustrations from other researchers. Pro golfers putt more accurately from all distances when putting for par than when putting for birdie because they fear the bogie more than they desire the birdie. Israeli parole boards grant parole to about 35% of the prisoners they see, except when they hear a case in the hour just after mealtime. In those cases, they grant parole 65% of the time. Shoppers will buy many more cans of soup if you put a sign atop the display that reads Limit 12 per customer.

We are players in a game we don't understand. Most of our own thinking is below awareness. Fifty years ago, people may have assumed we are captains of our own ships, but, in fact, our behavior is often aroused by context in ways we can't see. Our biases frequently cause us to want the wrong things. Our perceptions and memories are slippery, especially about our own mental states. Our free will is bounded. We have much less control over ourselves than we thought.

This research yielded a different vision of human nature and a different set of debates. The work of Kahneman and Tversky was a crucial pivot point in the way we see ourselves.

They also figured out ways to navigate around our shortcomings. Kahneman champions the idea of adversarial collaboration — when studying something, work with people you disagree with. Tversky had a wise maxim: Let us take what the terrain gives. Don't overreach. Understand what your circumstances are offering.

For more, see Who You Are by David Brooks, October 20, 2011 at NYTimes.com.