Much attention is given to the quality of schools when it comes to producing well-adjusted children that become responsible adults, but new research indicates that it might be much more important and rewarding to focus efforts on the very early preschool years, especially from birth to three years. In a paper entitled "Biological Embedding of Early Childhood Adversity: Toxic Stress and the Vicious Cycle of Poverty in South Africa" by University of Cape Town-affiliated neurobiologist, Barak Morgan, he explains how negative signals from the environment add permanent small molecules called "epigenetic marks" onto DNA during early brain development, even before birth. It is during this time that it is critical for a child to acquire the skills needed to manage their emotions, control aggression and thrive as adults. After this period it becomes very difficult to change these pathways.
The nature vs. nurture debate is an old one. Most people know that we are at the mercy of genes inherited from our parents (nature), but it is not as well known that French scientists Francis Jacob and Jacques Monod won the Nobel Prize in 1969 for discovering that DNA is regulated by the environment (nurture). Morgan writes, "It has become clear that Nature and Nurture, genes and environment, are not only of equal importance, but form an inseparable whole."
The negative signals influencing brain development are more common in poor homes where parents are struggling to just survive and where violence, neglect, poor nutrition and a lack of nurturing may be found. Several years ago a Canadian researcher, Michael Meany found that the amount of licking and grooming received by baby rats in the first days of their lives influenced their response to stress. Those that received the least licking and grooming had more epigenetic marks on the brain's major stress gene. Those that received more attention were better able to cope with stress. It did not matter if the licking and grooming was provided by the biological mother or another rat.
Especially worrisome is that the negative imprinting onto DNA is passed on from one generation to the next, resulting in a continuous cycle of dysfunctional family life and poverty. Jack Shonkoff, director of Harvard's Center on the Developing Child, says, "The quality of the foundation we build in the first couple of years doesn't completely determine everything that is going to come later, but it nevertheless sets you up for a lifetime of good prospects for healthy development, or it puts you in a deep hole that says the risks are much greater that you will have problems across the board."
The type of stress that causes these problems is known as "toxic stress". It is stress that cannot be coped with or can only be coped with at great cost in comparison to "manageable stress", stress that can be coped with. Toxic stress can lead to autoimmune disorders, substance abuse, heart problems, depression, anxiety, poor social skills, teenage pregnancy, delinquency, and suicidal behavior.
The discovery that the effects of toxic stress cause biological changes and can be passed on to subsequent generations makes it obvious that breaking this cycle can have enormous social and economic benefits. But, of course, the usual obstacles of finances and politics are likely to hinder the steps necessary to do that, whether the approach is to fight poverty or to support primary caregivers. But, if more research is conducted that supports the nature and nurture viewpoint and the case for costly interventions can be supported by science, advocacy for them may grow.