For more than five decades, Daniel Kahneman, a Nobel Laureate and professor of psychology at Princeton, has been asking questions like this [A bat and ball cost a dollar and ten cents. The bat costs a dollar more than the ball. How much does the ball cost?] and analyzing our answers. His disarmingly simple experiments have profoundly changed the way we think about thinking. While philosophers, economists, and social scientists had assumed for centuries that human beings are rational agents””reason was our Promethean gift””Kahneman, the late Amos Tversky, and others, including Shane Frederick (who developed the bat-and-ball question), demonstrated that we’re not nearly as rational as we like to believe.
When people face an uncertain situation, they don’t carefully evaluate the information or look up relevant statistics. Instead, their decisions depend on a long list of mental shortcuts, which often lead them to make foolish decisions. These shortcuts aren’t a faster way of doing the math; they’re a way of skipping the math altogether. Asked about the bat and the ball, we forget our arithmetic lessons and instead default to the answer that requires the least mental effort.
Although Kahneman is now widely recognized as one of the most influential psychologists of the twentieth century, his work was dismissed for years. Kahneman recounts how one eminent American philosopher, after hearing about his research, quickly turned away, saying, “I am not interested in the psychology of stupidity.”