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.