Role-playing games are contests in which the players usually cooperate as a group to achieve a common goal rather than compete to eliminate one another from play.... Role games ... bring players together in a mutual effort.
Gary GygaxOf course as children, we all, in all cultures and societies, learn behavior from observation, imitation, and encouragement of various kinds. So by the suggestion made, we all 'pretend' most of the time.
Gary Gygax