Superforecasting: The Art and Science of Prediction

by Philip E. Tetlock

Kahneman first documented scope insensitivity thirty years ago when he asked a randomly selected group in Toronto, the capital city of Ontario, how much they would be willing to pay to clean up the lakes in a small region of the province. On average, people said about $10.3 Kahneman asked another randomly selected group how much they would be willing to pay to clean up every one of the 250,000 lakes in Ontario. They too said about $10. Later research got similar results. One study informed people that each year 2,000 migratory birds drown in oil ponds. How much would you be willing to pay to stop that? Other subjects were told 20,000 birds died each year. A third group was told it was 200,000 birds. And yet in each case, the average amount people said they would be willing to pay was around $80. What people were responding to, Kahneman later wrote, was the prototypical image that came to them—a polluted lake or a drowning, oil-soaked duck. “The prototype automatically evokes an affective response, and the intensity of that emotion is then mapped onto the dollar scale.” It’s classic bait and switch. Instead of answering the question asked—a difficult one that requires putting a money value on things we never monetize—people answered “How bad does this make me feel?” Whether the question is about 2,000 or 200,000 dying ducks, the answer is roughly the same: bad. Scope recedes into the background—and out of sight, out of mind.