Research shows that head size growth in the first year of life relates to intelligence later (Gale et al., 2006). It doesn't matter how large the baby's head was at birth, it's what happens in the first year after birth that matters most.
How do babies grow after birth?
DNA synthesis occurs rapidly following conception and through the first years of life. Nerve growth factor is a hormone that facilitates development. Both are promoted by TOUCH.
When mothers stop touching their infants, DNA synthesis stops, growth hormone diminishes (Schaunberg, 1995). Physiologically, the baby goes into "survival mode."
Our ancestors carried and held (all the time) and slept with their babies, maximizing growth.
What else helps the baby grow?
Breastmilk. Use of infant formula is risky. It is greatly inferior to breastmilk in so many ways (I'll put this in a later blog). It linked to poor development of brain neurotransmitters and of the immune system which influence how the brain functions. Formula feeding is a risk factor for all sorts of diseases, large and small, including diabetes.
Breastfeeding encourages right brain development, the source of social emotions and practical intelligence. Breast milk fosters more efficient function=more intelligence.
Even adopting moms can breastfeed!
What deters growth?
Distress. Crying kills neurons.When the stress-response system kicks in, goodbye neurons. But the "other brain" is also affected. Too much stress suppresses glial cell division--and glial cells take care of myelinization at developmental plateaus (myelin is the capstone for a neuron and facilitates communication with other neurons).
It is advisable for a parent to be like an ancient traditionalist---anticipate the baby's needs by its movements, its restlessness. Don't let it get upset before tending to its needs. Figure out the specific holding and rocking patterns that it prefers and that calm it down.
(Traditional caregivers are even able to anticipate elimination in their babies when they carry them around, circumventing the need for diapers. Of course, most of the time we cannot follow this practice in the modern world!)
It's not surprising that these parenting principles have been around for 30 million years among catarrhine mammals (of which we are a part). These practices are shown to bring about intelligence by fostering a well-functioning body and brain.
Take home message: If you want a smart baby...
1, (Almost) NEVER PUT IT DOWN!
2, Keep it CALM.
3. Feed it MOTHER's milk. Plan and work to breastfeed for at least a year if not longer (ancestral patterns were 2-5 years; Hewlett & Lamb, 2005).
REFERENCES
Catharine R. Gale, PhD, Finbar J. O'Callaghan, PhD, Maria Bredow, MBChB, Christopher N. Martyn, DPhil and the Avon Longitudinal Study of Parents and Children Study Team (October 4, 2006). "The Influence of Head Growth in Fetal Life, Infancy, and Childhood on Intelligence at the Ages of 4 and 8 Years". PEDIATRICS Vol. 118 No. 4 October 2006, pp. 1486-1492. http://pediatrics.aappublications.org/cgi/content/short/118/4/1486.
Hewlett, B., & Lamb, M. (2005). Hunter-gatherer childhoods.New York: Aldine.
Schanberg, S. (1995). The genetic basis for touch effects. In T. Field (Ed.), Touch and Early Experience (pp. 67-80). Mahwah, NJ: Erlbaum.
