They were the economist Amos Tversky and the psychologist Daniel Kahneman. Together, the two launched the field of behavioral economics—and Kahneman won a Nobel Prize—by showing that man is a very irrational beast. Feeling, they discovered, is a form of thinking.

But if you presented people with situations in which the evidence they needed to judge them accurately was hard for them to retrieve from their memories, and misleading evidence came easily to mind, they made mistakes. “Consequently,” Amos and Danny wrote, “the use of the availability heuristic leads to systematic biases.” Human judgment was