Several meta-analyses and systematic reviews converge on the same message. An analysis done in 72 countries shows no consistent or measurable associations between well-being and the roll-out of social media globally. Moreover, findings from the Adolescent Brain Cognitive Development study, the largest long-term study of adolescent brain development in the United States, has found no evidence of drastic changes associated with digital-technology use. Haidt, a social psychologist at New York University, is a gifted storyteller, but his tale is currently one searching for evidence.