When children are together, they develop their own rituals, traditions, games, and legends—essentially, their own folklore, or, as researchers call it, “childlore.” That lore can be widespread and long-lasting—the mind boggles to think how many generations of children have played tag, for instance.

As Iona and Peter Opie, two pioneers in the childlore field, wrote in their 1959 book, The Lore and Language of Schoolchildren, “The scraps of lore which children learn from each other are at once more real, more immediately serviceable, and more vastly entertaining to them than anything which they learn from grown-ups.” And some information—such