As the Berlin Wall fell in 1989, many observers were shocked to see East German residents, once seemingly so loyal to their Communist government, cheering in the streets. Economist Timur Kuran dubbed the phenomenon a “preference cascade.” When people are pressured to conform, he wrote, they will hide their true beliefs for fear of censure or worse. And, since no one knows how many other people might share their heretical views, no one speaks up—until some rupture gives people the freedom to express their true preferences. Then the whole society seems to pivot at once; suddenly everyone admits the emperor has no clothes.