Abstract: Significant social change often comes from the unleashing of hidden preferences; it also comes from the construction of novel preferences. Under the pressure of social norms, people sometimes falsify their preferences. They do not feel free to say or do as they wish. Once norms are weakened or revised, through private efforts or law, it becomes possible to discover preexisting preferences. Because those preferences existed but were concealed, large-scale movements are both possible and exceedingly difficult to predict; they are often startling. But revisions of norms can also construct rather than uncover preferences. Once norms are altered, again through private efforts or law, people come to hold preferences that they did not hold before. Nothing has been unleashed. These points bear on the rise and fall (and rise again, and fall again) of discrimination on the basis of sex and race (and also religion and ethnicity). They also help illuminate the dynamics of social cascades and the effects of social norms on diverse practices and developments, including smoking, drinking, police brutality, protest activity, veganism, drug use, crime, white nationalism, “ethnification,” considerateness, and the public expression of religious beliefs.