Why Obama-Trump swing voters like heavy metal

ONE REASON America has become so polarised is that its two big parties are increasingly seen to represent tribes as well as policies. One study by Lilliana Mason of the University of Maryland found that whether people said they were “liberal” was a better predictor of reluctance to marry a “conservative”—and vice versa—than actual views on political issues were. Another paper, by Douglas Ahler of Florida State University and Gaurav Sood, found that Americans wildly exaggerate the share of each party’s voters made up by certain groups. On average, poll respondents guessed that 32% of Democrats were gay and that 38% of Republicans earned over $250,000. The real figures were 6% and 2%.