Note from Jon Haidt:Today we have a cross-post from Substack,. Jean was among the first psychologists to identify the move from flip phones to smartphones loaded with social media apps as a major cause of the adolescent mental health crisis as she was doing research for the 2017 book iGen. She received a great deal of pushback from other researchers at the time––and ever since––who claimed that she was mistaking correlation for causation. Skeptics of the smartphone theory generally offer their o...