Scan the newspaper headlines, or switch on cable news for a few minutes, and it’s easy to conclude that we are living through harsh, mean, divisive times. But a recent column in the Washington Post reminded me of a truth that is even easier to overlook: Just as bad behavior tends to spread, so too does good behavior. Kindness, it turns out, is contagious. The column highlighted the work of Stanford psychologist Jamil Zaki, who documents what he calls “positive conformity.” In his research, “participants who believed others were more generous became more generous themselves.” This suggests that “kindness is contagious, and that it can cascade across people, taking on new forms along the way.”