We’re big-brained altricial mammals, born helpless and requiring extensive adult care, who learn a wide variety of skills through different sorts of play. Much of what applies to the social development of nonhuman mammals and other animals also applies to us.
Basically, we can learn about the various reasons why animals play (why it has evolved and develops as it does) including its vital role in social development and socialization, physical exercise,development, and also for learning social skills concerning fairness, , and behavior. For example, the basic rules for fair play in animals also apply to humans, namely ask first, be honest, follow the rules, and admit you’re wrong. When the rules of play are violated, and when fairness breaks down, so does play.