The Undoing Project: A Friendship That Changed Our Minds

by Michael Lewis

Doubt is not a pleasant condition, but certainty is an absurd one. —Voltaire

He suggested a new definition of the nerd: a person who knows his own mind well enough to mistrust it.

Why had so much conventional wisdom been bullshit? And not just in sports but across the whole society.

“When someone says something, don’t ask yourself if it is true. Ask what it might be true of.” That was his intellectual instinct, his natural first step to the mental hoop: to take whatever someone had just said to him and try not to tear it down but to make sense of it.

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

Amos

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.

When people make decisions, they are also making judgments about similarity, between some object in the real world and what they ideally want.

By changing the context in which two things are compared, you submerge certain features and force others to the surface.

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.

“it is part of the human condition that we are statistically punished for rewarding others and rewarded for punishing them.”

Kahneman

When you are a pessimist and the bad thing happens, you live it twice,

Amos

“Even the fairest coin, however, given the limitations of its memory and moral sense, cannot be as fair as the gambler expects it to be,”

Well, even experts are human. “The clinician is not a machine,” he wrote. “While he possesses his full share of human learning and hypothesis-generating skills, he lacks the machine’s reliability. He ‘has his days’: Boredom, fatigue, illness, situational and interpersonal distractions all plague him, with the result that his repeated judgments of the exact same stimulus configuration are not identical. . . . If we could remove some of this human unreliability by eliminating this random error in his judgments, we should thereby increase the validity of the resulting predictions . . .”

Goldberg

If they both committed the same mental errors, or were tempted to commit them, they assumed—rightly, as it turned out—that most other people would commit them, too.

people faced with a problem that had a statistically correct answer did not think like statisticians. Even statisticians did not think like statisticians.

Human judgment was distorted by . . . the memorable.

not just that people don’t know what they don’t know, but that they don’t bother to factor their ignorance into their judgments.

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

Man’s inability to see the power of regression to the mean leaves him blind to the nature of the world around him.

“most advances in science come not from eureka moments but from ‘hmmm, that’s funny.’”

Biedersman

Once we have adopted a particular hypothesis or interpretation, we grossly exaggerate the likelihood of that hypothesis, and find it very difficult to see things any other way.

Amos

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

Amos

Just because the patient is better after I treated him doesn’t mean he got better because I treated him,

Redelmeir

“In math you always check your work. In medicine, no. And if we are fallible in algebra, where the answers are clear, how much more fallible must we be in a world where the answers are much less clear?”

Refelmeier

“They provided a language and a logic for articulating some of the pitfalls people encounter when they think. Now these mistakes could be communicated. It was the recognition of human error. Not its denial. Not its demonization. Just the understanding that they are part of human nature.”

Redelmeier

A part of good science is to see what everyone else can see but think what no one else has ever said.

Amos

So many problems occur when people fail to be obedient when they are supposed to be obedient, and fail to be creative when they are supposed to be creative.

Amos

They didn’t simply experience fixed levels of happiness or unhappiness. They experienced one thing and remembered something else.

“Last impressions can be lasting impressions.”

Redelmeier

“quite likely that the fate of entire societies may be sealed by a series of avoidable mistakes committed by their leaders.”

Kahneman

“No one ever made a decision because of a number. They need a story.”

Danny K.

Gamblers accepted bets with negative expected values; if they didn’t, casinos wouldn’t exist.

“It is a given that people who use mathematics have some glamour,” said Danny. “It was prestigious because it borrowed the aura of mathematics and because nobody else could understand what was going on there.”

The understanding of any decision had to account not just for the financial consequences but for the emotional ones, too.

“It is the anticipation of regret that affects decisions, along with the anticipation of other consequences.”

Danny

“What might have been is an essential component of misery,’”

Danny

Happy people did not dwell on some imagined unhappiness the way unhappy people imagined what they might have done differently so that they might be happy.

People did not seek to avoid other emotions with the same energy they sought to avoid regret.

When they made decisions, people did not seek to maximize utility. They sou...

“In defiance of logic, there is a definite sense that one comes closer to winning the lottery when one’s ticket number is similar to the number that won,”

Danny

People regretted what they had done, and what they wished they hadn’t done, far more than what they had not done and perhaps should have.

“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,”

Danny

“When one fails to take action that could have avoided a disaster, one does not accept responsibility for the occurrence of the disaster.”

Danny

The more control you felt you had over the outcome of a gamble, the greater the regret you experienced if the gamble turned out badly.

The odds that people demanded to accept a certain loss over the chance of some greater loss crudely mirrored the odds they demanded to forgo a certain gain for the chance of a greater gain.

When choosing between sure things and gambles, people’s desire to avoid loss exceeded their desire to secure gain.

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

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

The irrational behavior of the few would not be offset by the rational behavior of the many. People could be systematically wrong, and so markets could be systematically wrong, too.

“Science is a conversation and you have to compete for the right to be heard. And the competition has its rules. And the rules, oddly enough, are that you are tested on formal theory.”

Danny