Two new research papers, using very different methods, have both come to this conclusion. Betsey Stevenson and Justin Wolfers, economists at the University of Pennsylvania (and a couple), have looked at the traditional happiness data, in which people are simply asked how satisfied they are with their overall lives. In the early 1970s, women reported being slightly happier than men. Today, the two have switched places. Mr. Krueger, analyzing time-use studies over the last four decades, has found an even starker pattern. Since the 1960s, men have gradually cut back on activities they find unpleasant. They now work less and...