“We don’t stop playing because we grow old; we grow old because we stop playing.” – George Bernard Shaw
This is one of my favorite quotes. I wield it as my enlightened metaphor anytime I encourage adults to throw off their self-imposed cloak of mirthless responsibility, if only for a few moments, and recover a glimpse of their childhood, and I remind them that play is not reserved for those with fewer than 16 candles on their birthday cake.
Nearly a century after George Bernard Shaw wrote those words, scientists are discovering they may be more than metaphor. In fact, there is mounting evidence that play can promote neurogenesis and reverse some of the effects of aging in the human brain.
What is Neurogenesis?
Neurons are nerve cells that act as the raw materials of the human brain. During fetal development, these neurons migrate to different areas and become the parts of the brain that control basic human function such as breathing, hearing and smelling. They also make up the more advanced centers of the brain that control complex thought and regulate emotions. Until recently, scientists believed that neurogenesis, the creation of neurons, ceased at birth. This theory proposed that we were born with over 100 billion neurons and those were all we had to work with for our entire lives. Numerous health and environmental factors destroy brain cells as we age and so we are left with a theoretical hourglass in which neurons are the sand falling from one end to the other. When all of the neurons have slipped away, so do we.
It turns out there might be more to this story than a grisly and inevitable end. Studies since the 1960s in adult animals have been able to show evidence of neurogenesis when subjects were exposed to enriched environments, including instances of exercise and/or play. Skeptics have argued that there is not enough evidence to support neurogenesis in adult humans, but a new study appears to provide thorough information on the extent of adult neurogenesis and confirms the role of play and other environmental enrichments in neural development.
Neurons Go Nuclear
In the 1940s and 1950s, above ground nuclear testing caused an elevation of the Carbon-14 isotope (14C) in the atmosphere. 14C is taken up by plants and by animals that eat plants. It is therefore present in humans at a cellular level. The presence of 14C in the brain acts as a time stamp on every new-born brain cell. When levels of 14C are compared to the levels of Carbon-12 isotope in the human brain, which is stable and more abundant, scientists can measure the age of brain cells. This study performed such a measurement on the post mortem brains of 55 men and women between the ages of 19 and 92.
According to the study, nearly 1/3 of the neurons in the brain are regularly renewed throughout life, or approximately 1,400 new neurons per day. This “neural turnover” may enhance the function of the human brain, help regulate mood, and improve cognitive reasoning by maintaining a steady supply of younger neurons (Spalding et al 2013).
Drinking from the Fountain of Youth
Now that adult neurogenesis has been confirmed, you might be wondering how you can start the process in your own brain. What medicine or procedure can we employ to jumpstart the neural engines? It turns out George Bernard Shaw wrote that prescription decades ago: Play.
In 2008, Dr. Stuart Brown gave a talk on the importance of play. The nonprofit group TED, which hosts conferences around the world to spread new ideas and promote intellectual discovery, shared a video of Dr. Brown’s talk on their website where it has been translated into 24 languages and viewed nearly a million times. In his talk, Dr. Brown discusses how play, in all its forms, improves the cognitive function of the brain, improves contextual memory development and enhances our ability to explore and discover new things (Brown 2008).
Dr. Brown is not alone in his views on play and its essential role in our biological development.
One of the earliest and most exciting studies ever published regarding the effects of play on the brain was conducted by Marian Diamond in 1964 on laboratory rats. Diamond divided the rats into two groups. One group was raised in solitary confinement without any outside stimulation. The other group was raised in a colony filled with toys and playful activities. The former group had smaller brains and thinner cerebral cortices. The latter group had larger brains and exhibited higher intelligence, finding their way through mazes much more quickly (Diamond et al 1964). Further analysis of the same study showed that rats who were allowed to play had increased levels of brain-derived neutrophic factor (BDNF) in their brains. BDNF is essential for the growth and maintenance of neuron development (Gordon et al 2003). Although the study was limited to rats, ethical considerations prevented a similar study on humans, The 2013 Spalding study suggests it is very likely that play effects human brains in much the same way.
Other studies on human subjects reveal that children pay more attention in school after a period of unstructured free play (Pelligrini & Holmes, 2006) and that children who are allowed unstructured play with blocks performed better on divergent problem-solving and were more creative in their approach (Pepler & Ross 1981).
Play Isn’t Just an Appointment on Your Calendar
In our society, it isn’t uncommon for a person’s entire day to be condensed into a series of appointments on a calendar announced every quarter hour by a digital alarm emitted from a smart phone. Because we are so conditioned to set aside time for important meetings, doctor appointments and children’s dance recitals, it is understandable that your first reaction is to find a slot somewhere in your day to squeeze in a round of golf or a pickup basketball game. This is a good start, but it’s not enough.
Play is valuable, and any amount of play will be beneficial. But the benefits of play expand by orders of magnitude when play is a natural part of your everyday life. Infusing a playful mindset into your work can improve your problem-solving skills and social cohesion. People who have a rich play history are sought by leading corporations who understand that “tinkerers” are better equipped to resolve conflict, work as part of a team and perform complex tasks than candidates who have been play deprived (Brown 2008).
Incorporating playful activities into family life can reduce stress and enhance the dynamic of your collective and individual relationships. Children who are encouraged to play perform better in school. Parents who play are better equipped to manage tension, and there is evidence linking neurogenesis to a reduction in depression (Eisch & Petrik 2012) – a condition that affects over 120 million people and has an impact on the quality of life for those affected, as well as their entire family.
While there is still more research to be done, it appears that play represents a biological necessity, as important as sleep and exercise, that enhances the human condition and promotes neurogenesis and it’s positive impact on the human brain. By adopting a playful mindset and finding ways to infuse play into our everyday existence, we are enhancing our lives today and possibly prolonging them for years to come.
Dynamics of Hippocampal Neurogenesis in Adult Humans, Kirsty L. Spalding, Olaf Bergmann, Kanar Alkass, Samuel Bernard, Mehran Salehpour, Hagen B. Huttner, Emil Boström, Isabelle Westerlund, Céline Vial, Bruce A. Buchholz, Göran Possnert, Deborah C. Mash, Henrik Druid, Jonas Frisén, Cell – 6 June 2013 (Vol. 153, Issue 6, pp. 1219-1227)
Play is more than fun, Dr. Stuart Brown, MD, TED,www.ted.com/talks/stuart_brown_says_play_is_more_than_fun_it_s_vital, 2008
Socially-induced brain ‘fertilization’: play promotes brain derived neurotrophic factor transcription in the amygdala and dorsolateral frontal cortex in juvenile rats, Gordon NS, Burke S, Akil H, Watson SJ, and Panskepp, J., Neuroscience Letters 341 (1):17-20, 2003
The role of recess in primary school. Pelligrini AD and Holmes RM, 2006 The effects of play on convergent and divergent problem solving, Pepler DJ and Ross HS, Child Development 52(4): 1202-1210, 1981
Depression and hippocampal neurogenesis: a road to remission?, Eisch AJ, Petrik D., Science. 2012 Oct 5;338(6103):72-5. doi: 10.1126/science.1222941., 2012