A little more than a decade ago, researchers began tracking an alarming trend: a dramatic uptick in anxiety and depression among young Americans. Psychologist Jonathan Haidt, like many other researchers, says the increase is related to our use of social media and devices. But he believes it’s also deeper than that — connected to our deepest moral beliefs and how they shape the way we view the world. He says there are simple steps we can take to improve the mental health of kids growing up in the smartphone era.