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Why Is Play Good for Young Children?

A new study shows play’s effects on vagal tone. 


  • Children’s free play influences their physiological and psychological health.
  • Healthy vagal tone is associated with positive outcomes of all kinds.
  • Our study showed that recent free play experience predicted healthy baseline vagal tone.

new study my colleagues and I just published (Gleason et al., 2021) provides insight into how play influences a child’s physiological development, specifically vagal tone.

Our studies overall examine the effects of our species’ developmental system, or evolved nest, on child and adult well-being (physiological, social, moral). Self-directed free play with others, especially others of multiple ages, is part of humanity’s evolved nest heritage.  Other components of the evolved nest for young children that we are relating to well-being include breastfeeding, a welcoming social climate, positive touch and no negative touch, responsive care from several adult caregivers, nature immersion and connection, and routine healing practices.

In this study, we examined the effects of free play on vagal tone. Free play excludes organized sport activities or activities that adults direct. Instead, it refers to spontaneous, imaginative play that children invent together on the fly.

Animal studies show numerous effects of free play on neurobiological and social development. Over 1,200 genes are epigenetically (“turned on or off”) affected by play (Burghardt, 2005). In children, self-regulation systems are beneficially affected by play—delay of gratification (Cemore & Herwig, 2005) and emotion regulation (LaFreniere, 2011; Lindsey & Colwell, 2013). Executive functions are also facilitated by play (Thibodeau et al., 2016).

Our study was the first to examine and demonstrate the relation of play to adaptive physiology.

Adaptive physiological systems are part of a healthy personhood. Adaptive means that the body is able to adjust to the situation at hand—raising heart rate under challenge or decreasing heart rate when in a relaxing situation.  Play facilitates the growth of an adaptive physiology.

We measured adaptive physiology with respiratory sinus arrhythmia (RSA), the flexible responsiveness or adaptability of the vagus nerve (the 10th cranial nerve that innervates the major organs of the body). As part of the parasympathetic system, the vagus nerve inhibits the sympathetic nervous system’s threat-defensive systems (flight, fight, freeze). We refer to a vagus nerve response as “vagal tone.” Healthy vagal tone is associated with positive emotions and executive functions.

RSA is calculated by measuring how heart rate and breathing covary in situations of calm and situations of stress. Tonic vagal tone is measured at a single timepoint during relaxing situations, a baseline situation. Phasic vagal tone is measured across conditions—nonstressful to stressful and stressful back to nonstressful. Phasic vagal tone captures how adaptive the vagal tone of an individual is.

Our participants were mother-child dyads who were part of a longitudinal study. They came to the laboratory when the children were about five years old. There were 78 pairs with complete data.

To obtain a proxy for the children’s play experience generally, mothers completed a questionnaire about their child’s recent experience of the evolved nest (Evolved Developmental Niche Report; Narvaez et al., 2019). The play score was derived from two questions: In the past week, how much did the child play actively and freely with other children outside (play organized by the children; not organized activities)? and How much did the child play actively and freely with other children inside (play organized by the children, not organized activities and not passive watching).

Children’s RSA was evaluated in three conditions: baseline nonstressful (watching video of butterflies), stressful (completing a three-dimensional puzzle with timer), recovery nonstressful (watching video of happy babies).

The results indicated that the children’s baseline, or tonic, vagal tone was predicted by play experience in the last week. But the results did not show an effect of play on phasic vagal tone.

We concluded:

“Opportunities for social free play did not predict vagal flexibility, meaning that children whose mothers reported more play did not seem to have regulatory advantages in vagal flexibility; that is, they showed no evidence of a buffering effect of general play experience in the speed of their autonomic response to the stress of a cognitive task. Although these results seem inconsistent with the fact that play has been identified as a mechanism for coping with stress (Siviy, 2010; Yogman et al., 2018), research on play and stress has emphasized the benefits of playing while enduring cognitive, social, or emotional challenges, or play’s effectiveness in lowering children’s anxiety while experiencing stressful situations (Barnett & Storm, 1981). General play experience prior to stressful challenges thus might alter children’s static regulation, but detecting the effects of play on physiology in response to stress might require measurements of RSA that are concurrent both with the advent of a stressor and with children’s engagement in play.” (p. 5)

Play experience was related to higher tonic vagal tone at baseline which in other research corresponds with more positive outcomes, such as better cognitive performance and prefrontal neural functioning (Thayer et al., 2009). Our study adds to the converging evidence showing how important play is for health and well-being. Play enhances child health in multiple ways (Yogman et al., 2018). But it helps us all, as part of our long-time heritage as a species (Gray, 2013). As PT colleague, Peter Gray notes, play is not just for kids!


Burghardt, G.M. (2005). The genesis of animal play: Testing the limits. Cambridge, MA: MIT Press.

Cemore, J. J., & Herwig, J. E. (2005). Delay of gratification and make-believe play of preschoolers. Journal of Research in Childhood Education, 19(3), 251-266. doi:10.1080/02568540509595069

Gleason, T., Tarsha, M.S., Narvaez, D., & Kurth, A. (2021). Opportunities for free play and young children’s autonomic regulation. Developmental Psychobiology, 63 (6), e22134.

Gray, P. (2013). Free to learn. New York, NY: Basic Books.

LaFreniere, P. (2011). Evolutionary functions of social play: Life histories, sex differences, and emotion regulation. American Journal of Play, 3(4), 464-488.

Lindsey, E. W., & Colwell, M. J. (2013). Pretend and physical play: Links to preschoolers’ affective social competence. Merrill-Palmer Quarterly, 59(3), 330-360. doi:10.1353/mpq.2013.0015

Narvaez, D., Woodbury, R., Cheng, Y., Wang, L., Kurth, A., Gleason, T., … & Näpflin, C. (2019). Evolved Developmental Niche Provision Report: Moral Socialization, Social Thriving, and Social Maladaptation in three countries. SAGE Open, 9(2). doi: 10.1177/2158244019840123

Siviy, S. M. (2010). Play and adversity: how the playful mammalian brain withstands threats and anxieties. American Journal of Play, 2(3), 297-314.

Thayer, J. F., Hansen, A. L., Saus-Rose, E., and Johnsen, B. H. (2009). Heart rate variability, prefrontal neural function, and cognitive performance: the neurovisceral integration perspective on self-regulation, adaptation, and health. Ann. Behav. Med. 37, 141–153. doi: 10.1007/s12160-009-9101-z

Thibodeau, R. B., Gilpin, A. T., Brown, M. M., & Meyer, B. A. (2016). The effects of fantastical pretend-play on the development of executive functions: An intervention study. Journal of Experimental Child Psychology, 145, 120-138. doi:10.1016/j.jecp.2016.01.001

Yogman, M., Garner, A., Hutchinson, J., Hirsch-Pasek, K., Golinkoff, R.M., American Academy of Pediatrics Committee on Psychosocial Aspects of Child and Family Health; Council on Communications and Media (2018). The power of play: A pediatric role in enhancing development in young children. Pediatrics, 142(3), e20182058. doi:10.1542/peds.2018-2058

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