“Kahan devised a theory he calls “identity-protective cognition,” suggesting that when forced to choose between factual truth and group identity, most people choose the latter. “Individuals,” he concluded, “subconsciously resist factual information that threatens their defining values.” The problem wasn’t that people are dumb, irrational, or even superficial, as I’d formerly assumed. We’ve simply evolved—as a species—in a different way than I’d imagined. “Once group loyalties are engaged,” Haidt says, “you can’t change people’s mind by refuting their arguments.”