The Undoing Project: A Friendship That Changed Our Minds

by Michael Lewis

There were a great many interesting questions in the world to which the only honest answer was, “It’s impossible to know for sure.”

The central question posed by Gestalt psychologists was the question the behaviorists had elected to ignore: How does the brain create meaning?

“All your economic models are premised on people being smart and rational, and yet all the people you know are idiots.”

“The big choices we make are practically random. The small choices probably tell us more about who we are. Which field we go into may depend on which high school teacher we happen to meet. Who we marry may depend on who happens to be around at the right time of life. On the other hand, the small decisions are very systematic. That I became a psychologist is probably not very revealing. What kind of psychologist I am may reflect deep traits.”

When people make decisions, they are also making judgments about similarity, between some object in the real world and what they ideally want. They make these judgments by, in effect, counting up the features they notice. And as the noticeability of features can be manipulated by the way they are highlighted, the sense of how similar two things are might also be manipulated.

Things are grouped together for a reason, but, once they are grouped, their grouping causes them to seem more like each other than they otherwise would. That is, the mere act of classification reinforces stereotypes. If you want to weaken some stereotype, eliminate the classification.

“How do you understand memory?” he asked. “You don’t study memory. You study forgetting.”

“People’s intuitions about random sampling appear to satisfy the law of small numbers, which asserts that the law of large numbers applies to small numbers as well,”

“The production of a compelling scenario is likely to constrain future thinking,” wrote Danny and Amos. “There is much evidence showing that, once an uncertain situation has been perceived or interpreted in a particular fashion, it is quite difficult to view it in any other way.”

“When no specific evidence is given, the prior probabilities are properly utilized; when worthless specific evidence is given, prior probabilities are ignored.”

“He who sees the past as surprise-free is bound to have a future full of surprises.”

It is sometimes easier to make the world a better place than to prove you have made the world a better place.

The job of the decision maker wasn’t to be right but to figure out the odds in any decision and play them well.

“That was the moment I gave up on decision analysis,” said Danny. “No one ever made a decision because of a number. They need a story.”

The trouble, Danny suspected, was that “the understanding of numbers is so weak that they don’t communicate anything. Everyone feels that those probabilities are not real—that they are just something on somebody’s mind.”

Any theory pretending to explain how a rational person should take risks must at least take into account the common human desire to buy insurance, and other cases in which people systematically failed to maximize expected value.

When they made decisions, people did not seek to maximize utility. They sought to minimize regret.

“The pain that is experienced when the loss is caused by an act that modified the status quo is significantly greater than the pain that is experienced when the decision led to the retention of the status quo,”

The status quo was what people assumed they would get if they failed to take action. “Many instances of prolonged hesitation, and of continued reluctance to take positive action, should probably be explained in this fashion,”

For most people, the happiness involved in receiving a desirable object is smaller than the unhappiness involved in losing the same object.”

People’s emotional response to extremely long odds led them to reverse their usual taste for risk, and to become risk seeking when pursuing a long-shot gain and risk avoiding when faced with the extremely remote possibility of loss. (Which is why they bought both lottery tickets and insurance.) “If

People did not choose between things. They chose between descriptions of things.

“We study natural stupidity instead of artificial intelligence.”

Envy, in some strange way, required no imagination.

And any lawyer could at once make a case seem more persuasive, even as he made the truth of it less likely, by adding “representative” details to his description of people and events.