Julie Young

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Julie Young, a Boston-based behavioral analyst, center, sits with her sons Nolan, 3, left, and Jameson, 4, right, while looking at a smart phone at their home, in Boston, Monday, Jan. 27, 2014. Child development experts say it’s natural for toddlers to be fascinated with their own image, and that interest plays an important developmental role as they develop a sense of self. (AP Photo/Steven Senne)