Like 14 other people in my contacts, she can track my exact location at all times—just as I can track hers, along with those of my friends, roommates and old acquaintances. I’m 22 years old and, among ...

According to neuroscientist Ben Rein’s new book, Why Brains Need Friends, it comes down to our brains. As he explains in the book, that grey matter in our heads is exquisitely optimized for social ...