Steven Pinker is a professor of psychology at Harvard University and the author, most recently, of The Sense of Style: The Thinking Person?s Guide to Writing in the 21st Century.

Every now and again a society will fall into a moral panic, an extraordinary popular delusion, a madness of crowds. A danger is identified, spread by rumor, and amplified in the retelling, prompting extreme measures to combat the danger and?critically?denunciation of anyone who seeks to assess the danger or question the measures. The fear of denunciation leads to pre-emptive denunciation of others who fail to denounce, which snowballs into an intimidating consensus for increasingly draconian measures. Familiar examples include witch hunts, blood libels, red scares, wars on drugs, child abduction paranoia, and satanic-ritual day-care prosecutions. The moral panic du jour is campus rape: the extraordinary belief that America?s elite universities, the institutions into which the children of the upper middle class clamber to be admitted, have rates of rape that are higher than those of the world?s most savage war zones?even as quantitative studies have shown university women are less likely to be raped than their non-university age-mates, and that rates of rape overall have been in decline for decades.

A growing sexual-assault bureaucracy maintains a vested interest in fueling the panic, and anyone who questions it is a good candidate for a witness-protection program. A few brave commentators, including Erika Christakis, Heather MacDonald, and Christina Hoff Sommers, have spoken out, but a particularly timely and thorough analysis appeared this month in Slate: Emily Yoffe?s ?The College Rape Overcorrection.? Like her predecessors, Yoffe is adamant that rape is a serious problem requiring decisive measures of prevention and justice. But she meticulously shows how the current overreaction is doing far more harm than good, to women and men alike. Read it to understand not just this current obsession but the dynamic that leads to moral panics more generally.