All children, if given the chance, will play, preferably with other children. The games they play are often creative, rough and tumble, and of course - fun.
Some consequences are obvious:
• Fun is a positively reinforcing emotion. It makes kids happy.
• Play encourages exploration with fewer constraining boundaries than the drone of regular life.
• Play is an effective way to socialise and make friends.
• Play stimulates initiative and engagement, rather than passively observing what others do.
But there is another less obvious reason, one that is biological. In a review in the American Journal of Play (yes, there really is a scholarly journal on play), evidence is provided from controlled studies in rats and some primates. These studies show that when young animals are encouraged to play they develop improved social competence, cognition, and emotional regulation later in life. Play experience also makes them more adaptable to unexpected situations.
It is true that play is not a developmental feature in all species. The capacity (and need) for play is most evident in higher mammals with a well developed neocortex and that live in complex social environments. Play fighting is adaptive in predator species, like bears and lions that depend on aggression for survival as adults. In all species that exhibit juvenile play, play is a developmental tool that promotes the neocortical executive control regions to control other neural systems.
Play fighting is especially interesting because the juveniles must construct and obey certain rules. They intuitively recognise that they must not bite too hard, for example, and must give the opponent at chance to win sometimes or at least hold their own in the contest. The juveniles are clearly learning self-control, which will serve them well as adult. This reminds me of the touch football games or poison ball games that kids play.
Species that most obviously exhibit juvenile play are humans, dogs, cats, and ravens. In species where adults play, play can have immediate functions such as defusing social tensions and dominance relationships. Rats are an interesting case. They engage in juvenile play much more than other rodent species. Adult rats seem to exhibit novel mental capabilities, especially those involving social interactions that are not so prominent in other rodents.
*‘When members of a play-oriented species are denied access to juvenile play, they can become dysfunctional adults. For example, rats raised in social isolation show physical and chemical deficiencies in their brains and they have behavioural abnormalities linked to impaired executive control function. They show excessive anxiety to stressful or fear-inducing situations. They over-react to benign social interactions. They are less able to solve mental tasks.
Similar problems are seen in monkeys deprived of juvenile play. Being raised by a surrogate mother is emotionally and intellectually devastating, but less so if the surrogate is robot-like and can interact in play-like behaviour with the infant.’
Juvenile play sculpts the brain to be more adaptable later in life. In modern human society, juvenile play is often obstructed by such externals as over-scheduling, too much adult supervision, and too many restrictions. The restrictions are often for reasons of safety, which is understandable in today's world.
When I was a child, we had a lot more freedom to play, and in safety. It was not unusual in the summer time for a kid to leave home after breakfast and not return until dinner-time, going alone to a park or neighbour kid's house to play unsupervised as we wished. Sadly, that is too much freedom these days. In this respect anyway, the ‘good old days’ really were the ‘good old days’…
Source: *Pellis, S. M., Pellis, V. C., and Himmler, B. T. (2014). How play makes for a more adaptable brain. Ame. J. Play. 7 (1) 73-98