Superforecasting: The Art and Science of Prediction

by Philip E. Tetlock

This is an extreme case of what psychologists call “belief perseverance.” People can be astonishingly intransigent—and capable of rationalizing like crazy to avoid acknowledging new information that upsets their settled beliefs. Consider the 1942 argument of General John DeWitt, a strong supporter of the internment of Japanese Americans: “The very fact that no sabotage has taken place to date is a disturbing and confirming indication that such action will be taken.”6—or to put that more bluntly, “The fact that what I expected to happen didn’t happen proves that it will.” Fortunately, such extreme obstinacy is rare. More commonly, when we are confronted by facts impossible to ignore, we budge, grudgingly, but the degree of change is likely to be less than it should be. As we saw in chapter 2, the brain likes things neat and orderly and once it has things that way it tries to keep disturbances to a minimum.