Economists generally assume that more choices are better than fewer choices. But if that were so, argues Thaler, people would be upset, not happy, when the host at a dinner party removes the pre-dinner bowl of cashews. Yet many of us are happy that it’s gone. Purposely taking away our choice to eat more cashews, he argues, makes up for our lack of self-control. This simple contradiction between the economists’ model of rationality and actual human behavior, plus many more that Thaler has observed, leads him to divide the population into “Econs” and “Humans.” Econs, according to Thaler, are people who are economically rational and fit the model completely. Humans are the vast majority of people.

Thaler (1980) noticed another anomaly in people’s thinking that is inconsistent with the idea that people are rational. He called it the “endowment effect.” People must be paid much more to give something up (their “endowment”) than they are willing to pay to acquire it. So, to take one of his examples from a survey, people, when asked how much they are willing to accept to take on an added mortality risk of one in one thousand, would give, as a typical response, the number $10,000. But a typical response by people, when asked how much they would pay to reduce an existing risk of death by one in one thousand, was $200.

One of Thaler’s most-cited articles is Werner F. M. De Bondt and Richard Thaler (1985). In that paper they compared the stocks of “losers” and “winners.” They defined losers as stocks that had recently dropped in value and winners as stocks that had recently increased in value, and their hypothesis was that people overreact to news, driving the prices of winners too high and the prices of losers too low. Consistent with that hypothesis, they found that the portfolio of losers outperformed the portfolio of winners.

This is from the biography of Richard H. Thaler, the winner of the 2017 Nobel Prize in Economic Science. Read the whole thing here.

Thanks to Tyler Cowen and Lauren Landsburg for particularly helpful comments.

Richard and co-author Sendhil Mullainathan wrote the piece on behavioral economics in the 2008 edition of The Concise Encyclopedia of Economics.