Rolling down a hill in a park in Ottawa, Canada, with my 12 year old son and 9 year old daughter.
Climbing in trees to play Barbie vs. GI Joe with my brother when we were 10 and 8.
Pretending the couch is a small raft in a dangerous river of lava that required jumping from the “raft” to the “island in the lava river” (i.e., the chair) to avoid the lava spewing up while also pushing my 5 year old brother off the “raft” so that I could “save” him from the lava.
As we have seen all this week, whether an adult or a kid, a bird or a rat, a turtle or a dolphin, play emerges in many contexts and forms.
Some people prefer to play with words, making up jokes or puns.
Some people like games – card games, board games, ball games, computer games, pretend and role-playing games, puzzles.
Some people like to test their physical limits – rough-housing, playing king of the hill or ring-around-the rosy, jumping off things, flying high on a swing, sky-diving.
And some people like to create things – writing, drawing, building things, carving, concocting “potions”, cooking, baking, painting, welding, gardening.
The Good: Play is Easy to Identify
Play appears to be ubiquitous in humans of all ages, possibly appearing as early as 4 to 6 months when infants begin testing their surroundings and make things rattle, squeak, and bang. This was first identified by Jean Piaget and later examined by Philippe Rochat (1989). Free play increases as children age, as Belsky and Most reported in 1981, with pretend play and imaginary friends developing as children become more self-aware and begin to master language and reading behavioral cues (discussed in three articles by Artin Göncü, Tracy R. Gleason, and Lili Ma published in Learning and Behavior’s special issue on play).
Children often re-kindle adult interest in play as parents fight off monsters that live under their children’s bed each night and travel to distant places on our dragons and unicorns while riding around on “horses” better known as brooms.
Animals also remind us of the freedom that play provides to just let loose. Whether it is ravens soaring on air currents, killer whales surfing waves, or juvenile vervet monkeys performing acrobatic moves during a play fight (figure below), play is universal across species.
As described by Gordon Burghardt in his seminal book “The Genesis of Animal Play” (2005), which he echoed in yesterday’s post, and recently followed up by Vladimir Dinets (2015), even reptiles manipulate toys that make noise and play tug-a-war with hoses. Turtles chase balls; crocodiles hold them:
In their paper for the special issue, Serge Pellis and Vivian Pellis describe play-fighting in red-river hogs (image below) and warty pigs, which consists of aggressive pushing and shoving during head-to-head competitions until one of the contestants “loses”. This play fight is signified by the use of a “submission” signal between the two contestants, which terminates the “contest”. This signal does not occur during true fights.
A “Playful” Workshop
As described by Alex De Voogt in his introductory post, 16 experts in play from around the world attended the meeting that ultimately gave rise to the special issue and this digital event. The goal of the workshop was to define play in a way that could increase cohesion across the diverse fields represented. For three days, we heard from developmentalists studying pretense and imaginary friends in human children and the importance of play for children with chronic medical issues, to cognitive psychologists and anthropologists studying the influence of various games on cognitive abilities and socialization processes. Cindy Clark’s post earlier this week illustrates these socialization processes. We also heard from experts in animal behavior about the forms and potential functions of play in a variety of species, including reptiles, birds, horses, marine mammals, pigs, cows, and various rodents.
And each day, after intense discussions and a number of presentations, we enjoyed the hospitality of Brookfield Zoo where we had several opportunities to “play” ourselves: we interacted with a number of birds, watched children enjoy the beautiful weather and open grounds of the zoo, and of course watched plenty of animals play.
The Bad: An Impossible Dream?
After all of the talks were given, we were tasked with the difficult question of how to define, unify, and plan for the future of play. What are the functions of play? How did play evolve across a myriad of taxa and contexts? Can and should play be used as an indicator of an individual’s current welfare state?
As part of the evolutionary question, are play signals present in all species?
Dogs bow to one another, primates display play faces, humans smile. What about birds, pandas, and marine mammals? What is the function of these stereotyped displays? Elisabetta Palagi and Chiara Scopa believe these displays may have evolved to facilitate social communication through mimicry, a topic they discuss in their special-issue article.
As both Marek Špinka and Gordon Burghardt described in their posts, some animal models have progressed to mapping the neurophysiology of play (e.g., rodents) and have tested the effects social play and its deprivation on the immediate and future behavioral and neurophysiological outcomes.
Unfortunately, three days were insufficient to answer all of these questions. But, as we agreed at the end of the workshop, it is critical for scientists studying play to open their minds and begin to address these difficult questions. The posts this week have extended our initial efforts from 2016, with Špinka discussing the idea that perhaps a “play engine” powers the varied components of play across myriad species, and Burghardt picking up where we left off with the need to examine play from all sides and disciplines as we attempt to integrate and expand our knowledge of play into a cohesive theory.
Crossing the Line
Burghardt discusses the need for a comparative approach in the study of play in his post. As comparative psychologists, we straddle both sides – humans and non-human animals. Fascinated by the use of play as indicator of animal welfare and the current lack of evidence that cognitively challenging games, such as chess, do not appear to have any clear-cut cognitive benefits, I left the workshop with mixed feelings: excitement and trepidation for the monumental task at hand. Burghardt expressed these very thoughts in his post, and they were also echoed by Špinka.
There is still so much to learn about the nature of play on each side before we can delve deeper into functions and more proximate mechanisms. First and foremost, we need a common terminology as expressed De Voogt in the opening post and by Lance Miller in his article in the special issue.
This week, we have read a number of posts about play in humans, from imaginary friends to elves on shelves to the “social glue” of many cultures. We have read a perspective about play in animals and the current state of the field. Written by experts in the field of play, each perspective, whether by an anthropologist, a comparative psychologist, or animal ethicist, reinforces that we all have the same goal – to better understand play and its consequences.
Play may be easy to identify, but it is definitely not easy to quantify or manipulate experimentally.
We argue that children need to play outside without structure (i.e., recess) to enhance their overall development (e.g., greater cognitive success, better social skills, improved physical health). Yet, we have not demonstrated the mechanisms involved that support these positive outcomes. These concerns were described by Špinka in his post.
Pursuing the origins of play, its characteristics, and mechanisms will provide us with better opportunities to evaluate its functions. Unfortunately, we must first uncover the characteristics of play and the neurological mechanisms underlying it to begin to address its possible functions. Studying non-human animals from a comparative perspective provides opportunities to evaluate universals and species-specific characteristics. Elisabetta Palagi and her colleagues have studied play in a number of primates using this comparative approach with some very intriguing results, especially with regard to play fighting and play faces. Palagi and colleagues share their perspective in their article on mimicry in play.
The Cornerstone of Life
To unravel the remarkable secrets of play, it is clear that we still have many more years of effort ahead of us. Knowing that rats laugh when tickled as Jaak Panksepp and his colleagues discovered, and some primates “grin” during play to minimize conflict, while the removal of play fight opportunities as young pups limits future social behavior in rats, are all steps to understanding the importance of play in animals – human and non-human. The posts this past week have emphasized both the importance and the mystery of play.
Despite the current state of organized chaos, one universal does exist: Watching others play is as delightful as play itself.
As my former mentor and one of the imagineers for this workshop, the late Dr. Stan Kuczaj, always said: “Life is short. Ride a roller coaster. Eat a hot dog. And most importantly play!”