Growing the Brain

In a previous blog I described a study that suggested creative activity encourages brain growth. Yesterday Nature Magazine published the results of another study that looked at brain development. This one linked income level to infant brain size.

Carried out by two researchers, Kimberly Noble from Columbia University and Elizabeth Sowell from LA’s Children’s Hospital, the study showed that infants from lower income families suffer a reduction in brain size. The implications of this study are that income disparity may have life-long, potentially irreversible consequences for children. These consequences go beyond the obvious disadvantage of diminished opportunity.  Even if at some point opportunity is equalized, children from low income homes may never be able to optimally exploit it.

Most of us are familiar with the nature/nurture debate.  Essentially, this discussion weighs the influence of environmental factors such as parenting, neighborhood and schooling against inherited traits. The Nobel/Sowell study, if it holds up, invalidates the debate. According to the study, nature is not a fixed element that can be juxtaposed against environment; it is a function of environment.

The observed effect of income level on brain size is so marked that even within lower income groups, variations of a few thousand dollars result in brain size disparity. If confirmed, the results of the Nobel/Sowell study ought to have a profound effect on the political dialogue that centers on economic equity.

Of thirty-three OECD countries,Chile, Mexico, Turkey, the United States and Israel were the five with the greatest income inequality.  That inequality may translate into millions of lifetimes of relative disadvantage.  Expand the focus of the results globally and a vast population, much of the world in fact, suffers that relative disadvantage.

It is true that we all want our children to maximize the potential with which nature has endowed them. But what if that potential is not fixed by nature? What if potential is at least partly a man-made artifact, a consequence of political and economic policies that perpetuate income inequality?

The authors of the Children’s Hospital/Columbia study are careful to explain that they don’t know exactly which factors influence brain size in infants.  The researchers guess the factors might be the usual suspects: nutrition, exposure to toxins, poor social stimulation. They suggest that tinkering with manageable factors during gestation and afterwards might have a beneficial influence.

However, it seems to me that the researchers pull back from the obvious remedy: close the income gap. This prescription, though obvious, is one that many people will find ideologically unpalatable.  Whenever wealth distribution is discussed there’s inevitably talk about freedom and choice. Which begs the question, what choice is given to an infant who lies in a crib with a destiny diminished by low income? What freedom does that infant have to forge a successful future?

Of course, there’s a larger issue than the individual tragedy of lost potential.  There’s the societal cost.  Children with less potential become adults who are less able. That is not in anyone’s interest, no matter their income level.

brain development
Credit for this image goes to Van Essen Lab(Washington University in St. Louis), in collaboration with Terrie Inder, Jeff Neil, Jason Hill, and others. The image illustrates human cortical development through gestation and into adulthood.

2 thoughts on “Growing the Brain

  1. There is no doubt that levels of family income effect all facets of child development. We know that children grow taller now than even in the mid 20th Century. We can safely assume that nutrition has a great deal to do with that situation. That generality can be documented with statistics – however . . .

    Assuming that increased height is a benefit and that greater brain size results in greater capabilities are not scientific conclusions. It is not difficult to find tall brilliant poor folks (Abraham Lincoln). Nor is it difficult to find short less intelligent rich folks, though they don’t make history and are not as easily mentioned by name.

    In addition, we have recently realized that the brain is elastic and changeable to the the end of life, though we once thought it fixed in late childhood and could not be improved thereafter. With increasing interest in the brain as a research topic and with the help of modern technology, neuro-plasticity is well-documented in all decades of a life span that is free from dementia or other brain disorders.

    Although each of us has gifts of nature, human capability seems to be largely a matter of personal determination. To think we can engineer human capacity through nutrition programs, income equality, genetic manipulation, or breeding a master race is not our prerogative. That is not to say that we should ignore the need that is around us. We have the obligation to help each other. Let me repeat that we have the obligation to help each other.

    But income equality is a pipe dream. It has never and will never happen.


    • Dreams are aspirational, and certainly other societies, not that different from ours, manage to do a better job of achieving the aspiration of income equality. Breeding a master race of course has the suggestion of eugenics; we’ve been there, done that. No one’s talking about eugenics. What I’m talking about is a more level playing field.
      You speak about neuro-plasticity. I speak about epigenetics–gene expression turned on or off by environmentally triggered switches. That alters destiny. That is science, not conjecture.


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