Along with Vygotsky, I would contend that the greatest of play’s many values for our species lies in the learning of self-control. Self-control is the essence of being human. We commonly say that people behave like “animals,” rather than like humans, when they fail to abide by socially agreed-upon rules and, instead, impulsively follow their immediate drives and whims. Everywhere, to live in human society, people must behave in accordance with conscious, shared mental conceptions of what is appropriate; and that is what children practice constantly in their play. In play, from their own desires, children practice the art of being human.

4. Play is non-literal, imaginative, marked off in some way from reality.

Another apparent paradox of play, also pointed out by Vygotsky, is that play is serious yet not serious, real yet not real.  In play one enters a realm that is physically located in the real world, makes use of props in the real world, is often about the real world, is said by the players to be real, and yet in some way is mentally removed from the real world.

Imagination, or fantasy, is most obvious in sociodramatic play, where the players create the characters and plot, but it is also present to some degree in all other forms of human play. In rough and tumble play, the fight is a pretend one, not a real one. In constructive play, the players say that they are building a castle, but they know it is a pretend castle, not a real one. In formal games with explicit rules, the players must accept an already established fictional situation that provides the foundation for the rules. For example, in the real world bishops can move in any direction they choose, but in the fantasy world of chess they can move only on the diagonals.

The fantasy aspect of play is intimately connected to play’s rule-based nature. Because play takes place in a fantasy world, it must be governed by rules that are in the minds of the players rather than by laws of nature. In reality, one cannot ride a horse unless a real horse is physically present; but in play one can ride a horse whenever the game's rules permit or prescribe it. In reality, a broom is just a broom, but in play it can be a horse. In reality, a chess piece is just a carved bit of wood, but in chess it is a bishop or a knight that has well-defined capacities and limitations for movement that are not even hinted at in the carved wood itself. The fictional situation dictates the rules of the game; the actual physical world within which the game is played is secondary. Through play the child learns to take charge of the world and not simply respond passively to it. In play the child’s mental concept dominates, and the child molds available elements of the physical world to meet that concept.

Play of all sorts has “time in” and “time out,” though that is more obvious for some forms of play than others. Time in is the period of fiction. Time out is the temporary return to reality—perhaps to tie one’s shoes, or go to the bathroom, or correct a playmate who hasn't been following the rules. During time in one does not say, “I am just playing,” any more than does Shakespeare’s Hamlet announce from the stage that he is merely pretending to murder his stepfather.

Adults sometimes become confused by the seriousness of children’s play and by children’s refusal, while playing, to say that they are playing. They worry needlessly that children don’t distinguish fantasy from reality. When my son was four years old he was Superman for periods that sometimes lasted more than a day. During those periods he would deny vigorously that he was only pretending to be Superman, and this worried his nursery school teacher. She was only partly mollified when I pointed out that he never attempted to leap off of actual tall buildings or stop real railroad trains and that he would acknowledge that he had been playing when he finally did declare time out by removing his cape. To acknowledge that play is play is to remove the magic spell; it automatically turns time in into time out.

An amazing fact of human nature is that even 2-year-olds know the difference between real and pretend. A 2-year-old who turns a cup filled with imaginary water over a doll and says, “Oh oh, dolly all wet,” knows that the doll isn’t really wet. It would be impossible to teach such young children such a subtle concept as pretense, yet they understand it. Apparently, the fictional mode of thinking, and the ability to keep that mode distinct from the literal mode, are innate to the human mind. That innate capacity is part of the inborn capacity for play.

The fantasy element of play is often not as obvious, or as full-blown, in adults’ play as in children’s play. That is one reason why adults’ play is typically not of the 100% variety. Yet, I would argue, fantasy occupies a big role in much if not most of what adults do and is a major element in our intuitive sense of the degree to which adult activities are play. An architect designing a house is designing a real house. Yet, the architect brings a good deal of imagination to bear in visualizing the house, imagining how people might use it, and matching it with some aesthetic concepts that she has in mind. It is reasonable to say that the architect builds a pretend house, in her mind and on paper, before it becomes a real one.

When I say that my writing this blog is about 80% play, I am taking into account not only my sense of freedom about doing it, my enjoyment of the process, and the fact that I’m following rules (about writing) that I accept as my own, but also the fact that a considerable degree of imagination is involved. I’m not making up the facts, but I am making up the way of stringing them together, and I am imagining how you might respond to what I am writing. Sometimes my fantasy goes even further, and I imagine that the ideas I’m presenting will have certain positive effects on society. So, fantasy is moving me along in this, much as it moves a child along in building a sandcastle or pretending to be Superman. The fact that parts of my fantasy could possibly turn into reality does not negate its status as fantasy.

5. Play involves an active, alert, but non-stressed frame of mind.

This final characteristic of play follows naturally from the other four. Because play involves conscious control of one’s own behavior, with attention to process and rules, it requires an active, alert mind. Players do not just passively absorb information from the environment, or reflexively respond to stimuli, or behave automatically in accordance with habit. Moreover, because play is not a response to external demands or immediate strong biological needs, the person at play is relatively free from the strong drives and emotions that are experienced as pressure or stress. And because the player’s attention is focused on process more than outcome, the player’s mind is not distracted by fear of failure. So, the mind at play is active and alert, but not stressed. The mental state of play is what some researchers call “flow.” Attention is attuned to the activity itself, and there is reduced consciousness of self and time. The mind is wrapped up in the ideas, rules, and actions of the game.

This point about the mental state of play is very important for understanding play’s value as a mode of learning and creative production. The alert but unstressed condition of the playful mind is precisely the condition that has been shown repeatedly, in many psychological experiments, to be ideal for creativity and the learning of new skills. Such experiments are normally not described as experiments on play, but it is no stretch to interpret them as that. What the experiments show is that strong pressure to perform well (which induces a non-playful state) improves performance on tasks that are mentally easy or habitual for the person, but worsens performance on tasks that require creativity, or conscious decision making, or the learning of new skills. In contrast, anything that is done to reduce the person’s concern with outcome and to increase the person’s enjoyment of the task for its own sake—that is, anything that increases playfulness—has the opposite effect.