by HeeJee Yoon
art by Sydney Eze
We Used to Play
“What do you do for fun?”
Bogged down by a literature essay and a looming chemistry exam, I felt a fundamental lack of playful energy in my life. Looking for inspiration, I asked my friend and fellow Grey Matters member, Ben, what he did for fun. Despite being a simple question, it elicited a complicated response consisting of a shrug and a look of disbelief at our inability to answer such a simple question. We shared bittersweet laughter, joking that this is the epitome of the "Columbia experience": constantly living under the slogan of ‘work hard, play hard,’ but somehow always leaving out the second half of the motto.
I decided a better person to ask about fun would be my 10-year-old self. So, I asked her, “How do you have fun?” Graciously stopping in the middle of a game of tag, she pants, “Play, of course.”
This straightforward response prompted me to consider: what exactly is play? According to Dr. Stuart Brown, a psychiatrist at the National Institute for Play, play is an activity pursued for its own sake—not for profit or recognition. It's voluntary, energizing, and takes us beyond ourselves [1].
Reflecting on the importance of play in my own childhood and in the lives of others, I wonder: what role does play serve, and should I prioritize fostering this spirit of playfulness amidst the demands of college life?
We Play to Survive
From the intense wrestling matches of young wolves to the intricate social games of primates, play permeates the tapestry of mammalian life, hinting at deeper evolutionary significance where play is more than just child's play—it's a serious business. Initially, theories such as the surplus energy hypothesis proposed that play was nothing more than a way for young animals to expend their excess energy [2]. However, Karl Groos, a German philosopher and psychologist in the 20th century, proposed an evolutionary perspective, suggesting that play serves as a strategic investment in teaching the young how to survive [3]. The seemingly pointless roughhousing actually provides a training ground for animals to develop skills crucial for navigating the survival challenges of an environment, from mastering evasion tactics to honing social interactions and dominance displays [3].
Though humans aren’t constantly preparing to flee from predators, our brains still carry our ancestors’ survival instincts in the form of the triune brain [4]. Paul MacLean’s idea of the “triune brain” highlights three key brain regions: the brain stem, the limbic system, and the cortex [5]. MacLean hypothesized that these regions were amongst the most important in coping with environmental stress, placing extra emphasis on the limbic structures [6]. These structures, deeply intertwined with emotional response and instinctive survival mechanisms, serve as vital hubs for memory and emotion regulation, epitomized by the hippocampus and amygdala [6]. Even across evolutionary history, these limbic structures have remained remarkably unchanged, suggesting their fundamental importance [5].
Indeed, research suggests that damage to the limbic structure in hamsters results in a noticeable decline in their play activity [7]. In contrast, altering the neocortex, a relatively newer brain region found on the surfaces of the brain, does not significantly affect their play behavior [7]. Such results confirm the significance of evolutionary-conserved brain regions tasked with shaping human play behavior.
This is not to say that recently evolved brain regions have no impact on play. In fact, emerging research shows that even recently evolved brain regions, such as the prefrontal cortex, an area responsible for making judgment calls and regulating emotions, play a significant role in shaping both play behavior and survival instincts. A study conducted by Dr. Sergio Pellis involved denying rats the opportunity to engage in rough-and-tumble play, a category of play characterized by physical fighting and wrestling [8,9]. As a consequence,
deficiencies emerged in their brain’s prefrontal cortex. Pellis observed that rats deprived of play exhibited impaired decision-making abilities in survival scenarios. For instance, when an adult male rat was introduced into a foreign cage, the resident rat perceived them as an intruder and initiated a fight. A typically-developed rat would cleverly find a place to hide and remain there. However, a play-deprived rat, lacking the well-developed prefrontal cortex necessary for sound judgments, would endure a beating and then inexplicably return to the area to engage in further conflict, thereby drawing more attention to itself [8,9]. Dr. Sergio Pellis's research underscores the vital role of rough-and-tumble play in rats for developing crucial survival skills and decision-making abilities, emphasizing its significance in shaping adaptive behavior. We will continue to explore these regions in the limbic systems and neocortical regions as they apply to different play scenarios.
We Play to Exercise our Brain
The classic game of tag is more than just an exhilarating opportunity to demonstrate your prowess against a playground enemy; it’s an opportunity to practice and enhance your executive functioning. Executive functioning refers to the ability to perform complex cognitive tasks like attending to specific stimuli, problem solving, and practicing mental flexibility (Diamond, 2014). Mastery of executive functions is important for the success of children in both academic and social settings as they grow up, and has proven itself as a reliable predictor for competence as rated by teachers and parents in later education [11].
Executive functions employ brain regions like the hippocampus, a region recognized as the primary structure for memory [12]. In the lively game of tag, children unwittingly give their hippocampus a thorough workout. Of course, the act of remembering who’s “it” and who’s not flexes this cognitive muscle. Surprisingly, it’s the act of fleeing during the game that truly builds this memory center.
To understand this concept, first, we turn our attention to the structure of the memory center. Like all brain regions, the hippocampus is made of brain cells called neurons that arrange themselves into networks in order to communicate with each other. The best hippocampal networks are the ones that are constantly changing and growing based on new experiences and environments. Returning to the idea of tag, a key component of the game is the constant aerobic exercise. The long strides needed to escape from the tagger increase the amount of brain-derived neurotrophic factor (BDNF), an important molecule involved in allowing the hippocampus to operate optimally as a center for learning and memory [13]. BDNF makes our brain extra flexible in a way that benefits us. This molecule allows for synaptic plasticity, meaning it can change how strong our neural connections are, which is important for proper brain network development [14]. Additionally, an increase in BDNF is associated with a process known as neurogenesis, which is the production of new brain cells [15]. This process allows for the formation of new neural connections and the pruning of unnecessary ones, essential mechanisms for learning, memory formation, and cognitive development during these critical periods of life.
Let’s refocus our attention on the synapse, the gaps between the neurons. Neurons communicate with each other through chemical messengers called neurotransmitters. In the process of fleeing from the tagger, our brain cells are ramping up the production of neurotransmitters associated with excitement, pleasure, and motivation–otherwise known as dopamine and adrenaline [16]. This surge in neurotransmitter activity is particularly pronounced in the limbic system [17]. In navigating our surroundings, whether it be strategizing our next move or assessing potential escape routes, our actions are influenced by perceptual and value-based decision-making processes. Perceptual decision-making involves interpreting sensory information to make judgments about our environment, while value-based decision-making entails weighing the potential outcomes against our internal values and goals. Even amidst heightened activity in our limbic system, which is flooded with dopamine and adrenaline in response to various stimuli, we are continually refining our ability to operate effectively. This means that despite the emotional arousal that often accompanies our responses to stimuli during engaged activities, we enhance our capacity for reasoned decision-making and action execution [17].
We Play to Create and Connect
In the whimsical world of childhood imagination, where Barbie dolls reign supreme, children embark on fantastical journeys limited only by the bounds of their creativity. Picture this scene: a child, armed with their trusty Barbie doll, orchestrates a grand adventure, casting the doll as the intrepid leader of an underground mermaid city. Amidst the glittering waves and hidden caverns, Barbie navigates treacherous waters and foils dastardly plots—all in a day's play.
At the heart of this cognitive marvel lies the prefrontal cortex, a brain region teeming
with promise, waiting for enriching activities like pretend play to reach its maximum potential. In the field of neuroscience, creativity is highly related to the concept of divergent thinking, the cognitive ability to come up with ideas that lead in various directions [18].
Divergent thinking is most commonly used during pretend play when children suggest alternate uses for objects or create novel scenarios to roleplay. Neuroimaging studies have shown that areas in the prefrontal cortex are activated when participants are engaged in divergent thinking [19, 20]. Recall the role of the prefrontal cortex, a region associated with planning, prioritizing, and overall maturity. This is one of the last regions in our brain to develop because of its high cognitive functions [21]. Exercising this region early on through the low-stress situation of pretend play sets children up for healthy and productive cognitive development [22].
But what drives this creative endeavor? The hippocampus, the brain's memory hub, re-enters the discussion. As children weave Barbie through their fantastical narratives, they draw upon a rich tapestry of memories, infusing their play with depth and continuity. Neuroscientists have observed the hippocampus lighting up with neural activity as children recall past adventures, highlighting its crucial role in shaping the narrative landscape of pretend play [23].
As children chart new territories with Barbie by their side, they engage in a form of mental time travel—a phenomenon rooted in the intricate interplay of episodic memory and future planning. Studies with rodents navigating mazes have unveiled the neural underpinnings of this cognitive marvel, with the hippocampus playing a pivotal role in constructing cognitive maps and anticipating future navigational paths [24, 25].
But what about the metacognitive dexterity at play? Pretend play offers a fertile ground for the cultivation of metacognitive skills—the ability to think about one's own thinking [22]. As children navigate the twists and turns of their Barbie-inspired adventures, they engage in reflective imagination, pondering the motivations and intentions of their doll counterparts. This metacognitive mastery is underpinned by the gradual maturation of the brain's reflective circuits, paving the way for heightened self-awareness and social understanding [26].
A research study investigated this aspect of pretend play in-depth, observing its effect on developing social skills, particularly empathy, in children [22]. It has been widely established that the posterior superior temporal sulcus (PSTS) is a brain region associated with developing social understanding and empathy. Researchers used a functional neuroimaging technique called functional near-infrared spectroscopy to measure the activity in this region during pretend play. They discovered that in comparison to solo play on tablets, pretend play was associated with greater activation in the PSTS. Interestingly, this brain region was not only active when kids were playing pretend with other kids, but also when they played on their own [22].
We Play to Heal
Play therapy, particularly when applied to trauma treatment, engages intricate neurobiological processes, including the hypothalamic-pituitary-adrenal (HPA) axis [27]. The HPA axis serves as a central regulator of the mammalian stress response, orchestrating a cascade of hormone and neurotransmitter signals in response to stressors [27]. In response to a perceived threat, neurons in the hypothalamic paraventricular nucleus (PVN) release corticotropin-releasing hormone (CRH) [28]. This hormone traverses to the anterior pituitary gland, stimulating the secretion of adrenocorticotropic hormone (ACTH) [28]. ACTH then acts upon the adrenal glands, prompting the release of glucocorticoids, steroid hormones primarily involved in regulating metabolism and immune response, such as cortisol, into the bloodstream [29]. Glucocorticoids play multifaceted roles in modulating metabolism, immune function, and neural activity, thereby coordinating physiological and behavioral responses to stress [29]. In the context of trauma, dysregulation of the HPA axis is frequently observed, leading to abnormal cortisol levels and heightened stress responses [29].
Interestingly, play therapy appears to exert regulatory effects on the HPA axis, potentially mitigating the adverse impacts of trauma-induced dysregulation [30]. By providing a safe and supportive environment for expression and exploration, play therapy
may attenuate hyperactivity within the HPA axis, thereby promoting a return to homeostasis and facilitating stress recovery [30]. Furthermore, the physiological effects of play therapy encompass not only the interactions of the hypothalamic-pituitary-adrenal (HPA) axis, but also involve other brain pathways related to the release of oxytocin– a hormone involved in social bonding, trust, and stress modulation [31]. The release of oxytocin is associated with positive social interactions, including those facilitated by play therapy [31].
Through interactive and engaging activities inherent to play therapy sessions, individuals may experience heightened oxytocinergic activity, fostering feelings of trust, safety, and relaxation [32].These neurochemical changes could counteract the negative effects of trauma, promoting emotional regulation and resilience [32].
Play therapy operates within a neurobiological framework encompassing the HPA axis and oxytocinergic system. By modulating stress-related neuroendocrine pathways, play therapy offers a promising avenue for trauma recovery, providing individuals with a safe and supportive environment conducive to healing and emotional regulation.
We Play to Have Fun
In a period of my life where time seems to be the most precious resource, I often find myself questioning the place of play in the realm of adulthood. Is it merely a relic of childhood to be discarded in the pursuit of success? Or, does it hold the key to unlocking a deeper, more fulfilling existence? Oftentimes, I can’t help but feel the opportunity cost of having fun and playing: I could be getting ahead on next week’s reading or contemplating acid-base problems. Delving into the neuroscience of play, I am reminded of the remarkable plasticity of the human brain. Contrary to popular belief, our brains are not static entities, but rather dynamic, ever-evolving structures capable of profound transformation throughout our lives. The concept of neuroplasticity teaches us that our brains have the remarkable ability to rewire and adapt in response to new experiences and environments, regardless of age. Through this article, I hope that one thing has become clear: the opportunity cost of NOT playing, where we risk losing out on moments for our brains to grow, heal, and laugh. As we climb the ladder of success, let's remember to pause and slide down the banister of playfulness every now and then.
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