It's a fancy name for just memory. Like what comes to mind easily and how that warps your judgment. For example, you're driving down the highway and you're going 75 miles an hour like everybody else. You're kind of assuming it's safe because nothing is alerting you to the probability of an accident. And then you see a horrible accident and everybody slows down to 50 because all of a sudden, probability of accident is more available. It's in your mind. So what comes easily in mind leads to all kinds of biases that people have named, the vividness bias. People think that a baseball player is a better baseball player than he is if his talents are very vivid. If he's really, really fast or has a lot of power, he's more likely to be overvalued than if he has subtle abilities like plate discipline because those aren't vivid. The decency bias is a consequence of the availability heuristic. It's whatever happened most recently is judged to be more probable and more likely. Hurricane hits New Orleans. Wipes it out. Everybody thinks hurricanes are more likely to hit New Orleans than they really

are and so forth.

A lot of Kahneman Dversky's research looked at how people think about risk and how we typically give adverse events a lot more weight than positive events. That was the thrust of their most influential paper published in 1979. It was called prospect theory, an analysis of decision under risk. It argued that the standard economic model for decision making didn't fully account for how real people make real decisions, especially if there's a possibility of a very bad outcome. It made sense that Kahneman and Dversky thought about this differently than economists. They were after all psychologists, but also they'd both seen some bad outcomes themselves. As a child, Kahneman survived the Holocaust, just barely in France. Dversky was a paratrooper and an infantry commander in the Israeli army and saw his share of death and disaster. Their own experiences with risk and adverse events informed what they thought about as scholars. They were both obsessed with how people process information, with how cognitive shortcuts get in the way of long-term logic, and especially with how we try in our minds to explain or even undo our worst experiences. The undoing project, the title of Michael Lewis's book, was also the name of the last project that Dversky and Kahneman worked on together. The nature of the project was they were going to explore the rules of

the human imagination.