iGen: Why Today's Super-Connected Kids Are Growing Up Less Rebellious, More Tolerant, Less Happy--and Completely Unprepared for Adulthood--and What That Means for the Rest of Us

by Jean M. Twenge

If an activity involves a screen, it’s linked to less happiness and more depression. If it doesn’t—particularly if it involves in-person social interaction or exercise—it’s linked to more happiness and less depression.