Nostalgia is overrated, a Harvard psychologist says. “The bad-dominates-good phenomenon is multiplied by a second source of bias, sometimes called the illusion of the good old days,” Harvard psychology professor Steven Pinker said at a forum sponsored by the Cato Institute last November. “People always pine for a golden age.” “They’re nostalgic about an era in which life was simpler and more predictable.” And Dr. Pinker has some cold water to throw at them, metaphorically speaking, of course. “When I told people that I was writing a book on why writing is so bad and how we might improve it,...