There is much controversy over what is needed for culture to flourish and what has led human culture to be different from “cultural” characteristics of other animals. Here I argue that the emergence of childhood as a step in the life cycle was critical to the evolution of the human cultural mind. My line of reasoning is built around two complementary features of childhood: imitation and play. When children imitate adults they routinely copy unnecessary and arbitrary actions. They will persistently replicate how an object is used, even when doing so interferes with their ability to produce the very outcome those actions are intended to bring about. Though seemingly maladaptive, this behavior provides for the faithful transmission of cultural ideas across generations. When children play together they commonly construct rules and meanings that exist purely because the players agree they “exist.” Play thus provides the building blocks with which children rehearse the kinds of institutional realities that typify cultural practices. I argue that these forms of imitation and play represent a foundation upon which human culture flourished and that neither are prevalent in nonhuman animals. In light of these arguments evidence will be assessed suggesting that childhood emerged relatively late in human evolution.