By, Michael Lewis
We’re obviously all at the mercy of forces we only dimly perceive and events over which we have no control, but it’s still unsettling to discover that there are people out there—human beings of whose existence you are totally oblivious—who have effectively toyed with your life. I had that feeling soon after I published Moneyball. The book was ostensibly about a cash-strapped major-league baseball team, the Oakland A’s, whose general manager, Billy Beane, had realized that baseball players were sometimes misunderstood by baseball professionals, and found new and better ways to value them. The book attracted the attention of a pair of Chicago scholars, an economist named Richard Thaler and a law professor named Cass Sunstein (now a senior official in the Obama White House). “Why do professional baseball executives, many of whom have spent their lives in the game, make so many colossal mistakes?” they asked in their review in The New Republic. “They are paid well, and they are specialists. They have every incentive to evaluate talent correctly. So why do they blunder?” My book clearly lacked a satisfying answer to that question. It pointed out that when baseball experts evaluated baseball players their judgment could be clouded by their prejudices and preconceptions—but why? I’d stumbled upon a mystery, the book reviewers noted, and I’d failed not merely to solve it but also to see that others already had done so. As they put it:
Lewis is actually speaking here of a central finding in cognitive psychology. In making judgments, people tend to use the “availability heuristic.” As Daniel Kahneman and Amos Tversky have shown, people often assess the probability of an event by asking whether relevant examples are cognitively “available” [i.e., can be easily remembered]. Thus [because they more readily recall words ending in “ing” than other words with penultimate “n”s, such as “bond” or “mane”], people are likely to think that more words, on a random page, end with the letters “ing” than have “n” as their next to last letter—even though a moment’s reflection will show that this could not possibly be the case. Now, it is not exactly dumb to use the availability heuristic. Sometimes it is the best guide that we possess. Yet reliable statistical evidence will outperform the availability heuristic every time. In using data rather than professional intuitions, Beane confirmed this point.