A recent study shows that non-addict siblings of drug addicts have similar deficits in circuitry for self-control (Ersche et al., 2012). The study has been reported as indicative of inborn capacities for self-control. BIG MISTAKE. It is jumping to a popular but incorrect conclusion (it's in the genes). There is much more evidence for an alternative conclusion.
We know now that U.S. caregiving environments are often deficient according to evolved expected care (see table below and here for more).
The Genome Project has shown us that very little is innate and that, contrary to expectations, only a couple percent of diseases are linked to specific single genetic deformities (Ansermet & Magistretti, 2004, Carey, 2011). Instead with the epigenetic revolution, we are finding out that most of who we become is formed by our experiences after conception (although the experiences of our parents and grandparents also affect our health; see Gluckman & Hanson, 2005, for a review).
Remember that humans are born (at full term—42 weeks gestation) with only 25% of the brain developed, with next to no immune system, and with all sorts of other brain and body systems to be established and interconnected. Most of this occurs in the first 6 years of life, co-constructed by caregivers and a built-in biological timetable that co-evolved with particular parenting practices (Trevathan, 2011).
For example, the baby's brain is growing so rapidly that human milk is designed for frequent ingestion (thin, not thick) which washes the brain with thousands of chemicals needed to build well-functioning systems.
How do we know that caregiving practices influence self-control?
Here are three examples how self-control capacities are shaped by early caregiving.
(1) Self-regulation is affected by experiences at birth.
Bystrova (2009) and colleagues conducted an experiment with newborn babies in the first hour after birth with four conditions. Some were placed on mother's chest skin to skin immediately after birth. A second group was wrapped up and placed in mother's arms. A third group was wrapped up and placed in a bed nearby and a fourth group was wrapped up and taken to another room. The experimenters observed the mothers and babies a year later. Although skin-to-skin babies did best, all those who had been placed on mother had a better relationship with mother and more self-regulation.
Separating mom and baby at birth (or any time in the first years) is a violation of evolved expected care. Yet hospital practices in the USA routinely separate mom and baby after birth, which if it occurs for too long can trigger a depressive reaction in the mother (whose body assumes the baby has died) (Trevathan, 2011). We have a epidemic of post-partum depression so great that it is now considered to be "normal"(Dawson et al., 2000).
(2) Parents shape self-regulation mechanisms, like vagal tone.
Vagal tone is a physiological mechanism highly related to social functioning. It is calculated from measuring heart rate variability, a rough measure of how well the vagus nerve controls resting heart rate. Vagal tone function is highly affected by caregiving, particularly touch, in early life (Porges, 2011). The degree of variability between breath inspiration and expiration is higher among those with good vagal tone, found among those with secure attachment. The myelinated vagus, along with cranial nerves, regulate facial expression and together constitute a social engagement system. Those with little variability have more difficulty handling negative emotions, as exhibited through behavioral inhibition to novel situations. This process represents the immobilization of the unmyelinated vagus, a self-protective mechanism that takes over when the other vagal functions were poorly developed during early life.
Letting babies cry is a common practice in the USA. Such experiences will foster poor vagal tone and poor health. Vagal function is related to most systems in the body and when poorly functioning can lead to numerous detrimental health outcomes (digestive—e.g., irritable bowel; neuronal communication—e.g., seizures; mental health-depression; see Ghanem et al. 2006; Groves et al., 2005). The vagus nerve can even prevent inflammation, an instigator of many diseases.
(3) Parenting turns genes off and on, shaping functioning for life-e.g., for anxiety.
Meaney and colleagues have documented differences in gene expression within the brain-body pituitary-adrenal stress axis, based on extent of maternal care soon after birth (Weaver, Szyf, & Meaney, 2002). Examining only one of hundreds of genes affected, Meaney and colleagues found that rats with high-caring (high licking, which translates to high touch) mothers in the first ten days of life had elevated gene expressions for glucocorticoid receptor proteins. (For humans, a corresponding critical period would be the first 6 months of life.)
Glucocorticoid hormones produced in all mammals in response to stress need to be switched off to prevent excessive stress, hippocampal dysfunction, and eventual depression. Rats with little maternal care had weaker feedback systems, resulting in more anxiety and lifelong heightened responses to stress across a diversity of brain and behavioral measures (Champagne & Meaney, 2001).
Moreover, there were spiraling generational effects. A low-nurturing mother bred low-nurturing daughters, compounding the effects of poor care on brain system development over generations (Weaver et al., 2002). Cross-foster studies show that the effect is environmental and not genetic (Francis, Diorio, Liu & Meaney, 1999).
Meaney and colleagues have now demonstrated the same mechanism occurring in the brains of human adults abused as children who subsequently committed suicide (McGowan et al., 2009).
Self Control Needs a Good Beginning
At a very basic level, self-control involves mechanisms that control stress reactivity and negative emotions. When a person's basic biology has been neglected in terms of evolved expected care in early life, he or she is set up to be stress reactive. See table. It is hard to remedy later.
These findings all have moral implications. If one does not feel at ease, how can one face new people, think outside the box and socially succeed? Instead, new things (e.g., people who look or act differently) are threatening and lead to immobilized thinking, feeling, relating, or worse, reactive aggression.
So come on, adults, let's get back to the wisdom of our ancestors-it matters how you support babies and young children. Ignore their needs, mistreat them, and you raise a troubled and troublesome human being.
Table. Early Life Childrearing Practices that Co-evolved with Needs of Young Child
(Hewlett & Lamb, 2005; Konner, 2010; Narvaez, in press)
Natural childbirth (no interference with timing, no separation, no induced pain)
Breastfeeding 2-5 years (among foraging hunter gatherers, average weaning age is 4)
Responsivity (needs met promptly, limbic resonance)
Nearly constant touch with movement
Multiple (close, caring) adult caregivers
Free play in nature with multi-aged mates
Deep social support of mom and baby
Positive social climate
Companionship care (mutual reciprocal relationship between caregiver and child)
Anisman, H., Zaharia, M.D., Meaney, M.J., & Merali, Z. (1998). Do early-life events permanently alter behavioral and hormonal responses to stressors? International Journal of Developmental Neuroscience, 16(3-4), 149-164.
Ansermet, F., & Magistretti, P. (2004). Biologic of freedom: Neural plasticity, experience, and the unconscious. New York: Other Press.
Bystrova, K., Ivanova, V., Edhborg, M., Matthiesen, A.S., Ransjö-Arvidson, A.B., Mukhamedrakhimov, R., Uvnäs-Moberg, K., Widström, A.M. (2009). Early contact versus separation: effects on mother-infant interaction one year later. Birth, 36(2), 97-109.
Caldji, C. Francis, D., Sharma, S., Plotsky, P.M., & Meaney, M.J. (2000). The effects of early rearing environment on the development of GABAA and central benzodiazepine receptor levels and novelty-induced fearfulness in the rat. Neuropsychopharmacology, March, 219-229.
Caldji, C., Diorio, J., & Meaney, M.J. (2003). Variations in maternal care alter GABA(A) receptor subunit expression in brain regions associated with fear. Neuropsychopharmacology, 28, 1950-1959.
Champagne, F. A., Weaver, I. C. G., Diorio, J., Dymov, S., Szyf, M., & Meaney, M.J. (2006). Maternal care associated with methylation of the estrogen receptor-alpha1b promoter and estrogen receptor-alpha expression in the medial preoptic area of female offspring. Endocrinology, 147(6), 2909-2915.
Champagne, F. & Meaney, M.J. (2001). Like mother, like daughter: evidence for non-genomic transmission of parental behavior and stress responsivity. Progress in Brain Research, 133, 287-302.
Champagne, F., & Meaney, M.J. (2007). Transgenerational effects of social environment on variations in maternal care and behavioral response to novelty. Behavioral Neuroscience 121, 1353-1363.
Champagne, F.A., & Meaney, M.J. (2006). Stress during gestation alters maternal care and the development of offspring in a rodent model. Biological Psychology, 59, 1227-1235.
Dawson, G., Ashman, S.B., & Carver, L.J. (2000). The role of early experience in shaping behavioral and brain development and its implications for social policy. Development and Psychopathology, 12, 695-712.
Ersche et al. (2012). Abnormal brain structure implicated in stimulant drug addiction. Science, 3335(6068), 601-604.
Francis, D., Diorio, J., Liu, D., & Meaney, M.J. (1999). Nongenomic transmission across generations of maternal behavior and stress responses in the rat. Science, 286, 1155-1158.
Francis, D.D. (2002). Naturally occurring differences in maternal care are associated with the expression of oxytocin and vasopressin receptors. Journal of Neuroendocrinology, 14, 349-353.
Francis, D.D., Diorio, J., Plotsky, P.M., & Meaney, M.J. (2002). Environmental enrichment reverses the effects of maternal separation on stress reactivity, Journal of Neuroscience, 22(18), 7480-7483.
Ghanem, T; Early, S (2006). "Vagal nerve stimulator implantation: An otolaryngologist's perspective". Otolaryngology - Head and Neck Surgery 135 (1): 46-51. doi:10.1016/j.otohns.2006.02.037. PMID 16815181.
Gluckman, P., & Hanson, M. (2005). Fetal Matrix: Evolution, development and disease. New York: Cambridge University Press.
Groves, Duncan A.; Brown, Verity J. (2005). "Vagal nerve stimulation: A review of its applications and potential mechanisms that mediate its clinical effects". Neuroscience & Biobehavioral Reviews 29 (3): 493. doi:10.1016/j.neubiorev.2005.01.004.
Hewlett, B.S., & Lamb, M.E. (2005). Hunter-gatherer childhoods: Evolutionary, developmental and cultural perspectives. New Brunswick, NJ: Aldine.
Konner, M. (2010). The Evolution of childhood. Cambridge, MA : Belknap Press.
Liu, D., Diorio, J., Tannenbaum, B., Caldji, C., Francis, D., Freedman, A., Sharma, S., Pearson, D., Plotsky, P.M., & Meaney, M.J. (1997). Maternal care, hippocampal glucocorticoid receptors, and hypothalamic-pituitary-adrenal responses to stress, Science, 277(5332), 1659-1662.
McGowan, P.O., Sasaki, A., D'Alessio, A.C., Dymov, S., Labonté, B., Szyf, M., Turecki, G., & Meaney, M.J. (2009). Epigenetic regulation of the glucocorticoid receptor in human brain associates with childhood abuse. Nature Neuroscience, 12, 342 - 348.
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.
Narvaez, D. (in press). Development and socialization within an evolutionary context: Growing Up to Become "A good and useful human being." In D. Fry (Ed.), War, Peace and Human Nature: The convergence of Evolutionary and Cultural Views. New York: Oxford University Press.
Porges, S. W. (2011). The polyvagal theory: Neurophysiologial foundations of emotions, attachment, communication, self-regulation. New York: W.W. Norton.
Trevathan, W.R. (2011). Human birth: An evolutionary perspective, 2nd ed.. New York: Aldine de Gruyter.
Weaver, I.C., Szyf, M., & Meaney, M.J. (2002). From maternal care to gene expression: DNA methylation and the maternal programming of stress responses. Endocrine Research, 28, 699.
POSTS ON PARENTING ISSUES AND CHILD DEVELOPMENT:
Links to other posts on infant sleep and sleep training:
SERIES ON CHILD FLOURISHING*
1. Kindness in Kids and the Nature-Nurture Debate (Dr. Sarina Saturn)
2. Why Synchronize and Bond With Your Children (Dr. Ruth Feldman)
3. “I want it—now!” How Children Learn Self-Control (Dr. Julie Braungart-Rieker)
4. Why Kids Should Be Protected from Toxic Stress (Dr. Bruce Perry)
5. “Mr. Mom” The New (or Old?) Normal (Dr. Lee Gettler)
6. Why Dad’s “Talk” is Important (Dr. Holly Brophy-Herb)
7. Conflict in the Family: Why Mom and Dad Should Say “Sorry” (Dr. Mark Cummings)
8. Domination or Partnership? How Does Your Family Stack Up? (Dr. Riane Eisler)
9. Why Carefully Invest Daily in a Child (Dr. Robin Nelson)
ALSO SEE: What is Child Flourishing?
NOTE on BASIC ASSUMPTIONS:
When I write about human nature, I use the 99% of human genus history as a baseline. That is the context of small-band hunter-gatherers. These are “immediate-return” societies with few possessions who migrate and forage. They have no hierarchy or coercion and value generosity and sharing. They exhibit both high autonomy and high commitment to the group. They have high social wellbeing. See comparison between dominant Western culture and this evolved heritage in my article (you can download from my website):
Narvaez, D. (2013). The 99 Percent—Development and socialization within an evolutionary context: Growing up to become “A good and useful human being.” In D. Fry (Ed.), War, Peace and Human Nature: The convergence of Evolutionary and Cultural Views (pp. 643-672). New York: Oxford University Press.
When I write about parenting, I assume the importance of the evolved developmental niche (EDN) for raising human infants (which initially arose over 30 million years ago with the emergence of the social mammals and has been slightly altered among human groups based on anthropological research).
The EDN is the baseline I use for determining what fosters optimal human health, wellbeing and compassionate morality. The niche includes at least the following: infant-initiated breastfeeding for several years, nearly constant touch early, responsiveness to needs so the young child does not get distressed, playful companionship with multi-aged playmates, multiple adult caregivers, positive social support, and soothing perinatal experiences.
All EDN characteristics are linked to health in mammalian and human studies (for reviews, see Narvaez, Panksepp, Schore & Gleason, 2013; Narvaez, Valentino, Fuentes, McKenna & Gray, 2014; Narvaez, 2014) Thus, shifts away from the EDN baseline are risky and must be supported with longitudinal data looking at wellbeing in children and adults. My comments and posts stem from these basic assumptions.
My research laboratory has documented the importance of the EDN for child wellbeing and moral development with more papers in the works see (my Website to download papers):
Narvaez, D., Gleason, T., Wang, L., Brooks, J., Lefever, J., Cheng, A., & Centers for the Prevention of Child Neglect (2013). The Evolved Development Niche: Longitudinal Effects of Caregiving Practices on Early Childhood Psychosocial Development. Early Childhood Research Quarterly, 28 (4), 759–773. Doi: 10.1016/j.ecresq.2013.07.003
Narvaez, D., Wang, L., Gleason, T., Cheng, A., Lefever, J., & Deng, L. (2013). The Evolved Developmental Niche and sociomoral outcomes in Chinese three-year-olds. European Journal of Developmental Psychology, 10(2), 106-127.
Also see these books for selected reviews:
Evolution, Early Experience and Human Development (Oxford University Press)
Ancestral Landscapes in Human Evolution (Oxford University Press)
Neurobiology and the Development of Human Morality (W.W. Norton)