Evolved Nest Companionship Is Our Species' Baseline
Avoid advice that violates our millions-year-old adaptation.
Posted February 21, 2022 | Reviewed by Hara Estroff Marano
Parents and adults from industrialized nations often misunderstand babies and their development. They are encouraged to look to “experts” and the latest experiments to figure out how to treat young children, even though the experts may not be experts in child development (e.g., Oster, 2019). Writer Jean Liedloff was the first to challenge the appropriateness of this approach to parenting after her experiences with the Ye’quana in the Amazon rainforest. What are industrialized parents and adults to do?
Here are three pieces of advice from this expert.
1. Understand the nature of a baby and her needs. Babies resemble fetuses until 18-21 months of age (Leakey, 1996; Montagu, 1968, 1970; Trevathan, 2011). They have high but decreasing malleability and plasticity neurobiologically, psychologically, and socially across the first years of life. The first five years shape the trajectories for neurobiological systems in terms of self-confidence, well-being, personality, sociality, and intelligences (e.g., social, emotional, cognitive, spiritual).
There are sensitive and critical periods for the development of different systems. Early life stress is toxic to developing systems (Garner et al., 2021; Lanius, Vermetten & Pain, 2010; Shonkoff & Garner, 2012; Schonkoff & Phillips, 2000).
2. Learn about our species' Evolved Nest. Babies expect what our ancestors adapted to, what helped them survive, thrive, and succeed across generations—our evolved nest. Because they are so immature, human babies evolved to expect their needs to be met immediately, which optimizes growth and development.
The evolved nest is a set of social and ecological circumstances typically inherited by members of a given species (Oyama et al. 2001). Converging evidence of of the importance of the evolved nest comes from several sciences: evolutionary studies, ethology, ethnography, neuroscience, clinical and developmental studies. Most components have been conserved for over 70 million years, reaching us through the social mammal line (Hewlett & Lamb, 2005). The evolved nest includes:
- Soothing pre- and perinatal experiences
- Breastfeeding on request for several years
- Affectionate (moving) touch; no negative touch
- A welcoming social climate
- Self-directed free play with multiple-aged mates
- Responsive relationships
- Multiple responsive stable supportive caregivers
- Nature immersion and connection
- Routine healing practices
Every evolved-nest component contributes to healthy brain development (e.g., Luby et al., 2012; Narvaez, 2014; Narvaez et al., 2013). The evolved nest initially acts like an external womb—meeting needs of child immediately to keep brain chemistry optimal. Babies (0-3) require nested companionship care to grow optimally.
Because humans are born so immature, much of our humanity develops postnatally (Narvaez, 2014). A stressed baby does not grow the vast social brain our ancestors evolved, leaving them more stress-reactive (e.g., Lupien et al., 2009). Animal studies show lasting effects on gene expression (e.g., Meaney, 2001).
The evidence for the evolved nest emerges from the broad swath of sciences that relate to human beings: evolutionary, biological, neuroscientific, archeological, anthropological, developmental, and clinical sciences. Only in recent decades have we developed the capacities to observe developmental contexts and their deep effects on individual well-being.
The evolved nest prioritizes baby’s well-being for the long term and for effects on society. Any move away from evolved practices is considered a risk factor.
3. Learn how to assess parenting books according to babies' evolved needs. Here are suggestions for what to consider.
- What credibility does the author have? Do they have a deep understanding of child development (e.g., relevant neuroscience)?
- What biases does the author have and are they made explicit? Does the author favor parent control over holistic child well-being? Is the author personally reputationally dependent on the findings presented, or funded by entities who are?
- What baselines (for what is normal) does the author adopt? Does the author describe them to the reader? Do the baselines fit with our species history, needs, development, and known clinical outcomes?
- Does the author provide specific details for study references (empirical evidence) for conclusions drawn? (This allows readers to look at the studies and draw their own conclusions.)
- Is there converging evidence from a broad science perspective for the findings cited?
- Do the author’s conclusions fit with our species' history, needs, and clinical outcomes?
Take home message: Our species’ evolved nest provides appropriate baselines for child-raising, proven adaptive over millions of years. Those who give advice ignoring these baselines are misunderstanding babies' needs.
Garner, A., Yogman, M., Committee on Psychosocial Aspects of Child and Family Health, Section on Developmental and Behavioral Pediatrics, Council on Early Childhood. (2021). Preventing childhood toxic stress: Partnering with families and communities to promote relational health. Pediatrics, 148(2), e2021052582
Hewlett, B.S., & Lamb, M.E. (2005). Hunter-gatherer childhoods: evolutionary, developmental and cultural perspectives. New Brunswick, NJ: Aldine.
Lanius, R. A., Vermetten, E., & Pain, C. (2010). The impact of early life trauma on health and disease: The hidden epidemic. New York, NY: Cambridge University Press.
Luby, Joan L., Deanna M. Barch, Andy Belden, Michael S. Gaffrey, Rebecca Tillman, Casey Babb, Tomoyuki Nishino, Hideo Suzuki, Kelly N. Botteron (2012). Maternal support in early childhood predicts larger hippocampal volumes at school age. Proceedings of the National Academy of Sciences, 109(8), 2854-2859.
Meaney, M. J. (2001). Maternal care, gene expression, and the transmission of individual differences in stress reactivity across generations. Annual Review of Neuroscience, 24, 1161–1192.
Montagu, A. (1968). Brains, genes, culture, immaturity, and gestation. In A. Montagu (Ed.), Culture: Man’s adaptive dimension (pp. 102-113). New York: Oxford.
Montagu, A. (1986). Touching: The human significance of the skin. New York: Harper & Row.
Narvaez, D. (2014). Neurobiology and the development of human morality: Evolution, culture and wisdom. New York: Norton.
Narvaez, D., Panksepp, J., Schore, A., & Gleason, T. (2013). Evolution, early experience and human development: From research to practice and policy. New York: Oxford.
Oster, E. (2019). Cribsheet: A data-driven guide to better, more relaxed parenting, from birth to preschool. New York: Penguin Press.
Oyama, S., Griffiths, P.E., & Gray, R.D. (2001). Cycles of contingency: Developmental systems and evolution. Cambridge, MA: MIT Press.
Shonkoff, J. P., & Garner, A. S. (2012). The lifelong effects of early childhood adversity and toxic stress. Pediatrics, 129(1), e232-246. doi: 10.1542/peds.2011-2663
Shonkoff, J. P., & Phillips, D. A. (2000). From neurons to neighborhoods: The science of early childhood development. Washington DC: National Academy Press.
Suttie, I. (1935). The origins of love and hate. New York, NY: The Julian Press.
Trevathan, W.R. (2011). Human birth: An evolutionary perspective, 2nd ed.. New York: Aldine de Gruyter.