Thursday, December 04, 2008

How Poverty Impacts Brain Development

The family we are born into has a profound influence on our life prospects. Indeed, from the earliest stages of fetal development, the diet and behaviour (e.g. smoking, consumption of drugs and alcohol, etc) of a prospective mother can significantly influence the physical and mental development of a child.

This study, for example, suggests that permanent vascular damage attributable to tobacco smoke exposure might be initiated in gestation. According to the American Academy of Child & Adolescent Psychiatry, prenatal exposure to alcohol is the most common cause of birth defects. Fetal Alcohol Syndrome can cause facial deformities, slow development and neurological problems.

This study in the Journal of Cognitive Neuroscience (and is covered in today's Globe) examines how postnatal poverty affects the brain development of children. Here is the abstract:

Social inequalities have profound effects on the physical and mental health of children. Children from low socioeconomic (SES) backgrounds perform below children from higher SES backgrounds on tests of intelligence and academic achievement, and recent findings indicate that low SES (LSES) children are impaired on behavioral measures of prefrontal function. However, the influence of socioeconomic disparity on direct measures of neural activity is unknown. Here, we provide electrophysiological evidence indicating that prefrontal function is altered in LSES children. We found that prefrontal-dependent electrophysiological measures of attention were reduced in LSES compared to high SES (HSES) children in a pattern similar to that observed in patients with lateral prefrontal cortex (PFC) damage. These findings provide neurophysiological evidence that social inequalities are associated with alterations in PFC function in LSES children. There are a number of factors associated with LSES rearing conditions that may have contributed to these results such as greater levels of stress and lack of access to cognitively stimulating materials and experiences. Targeting specific prefrontal processes affected by socioeconomic disparity could be helpful in developing intervention programs for LSES children.

Of particular interest are the kinds of environmental interventions that influence the brain development of children. The study notes the following: that environmental complexity can augment brain development; children from poor families have less to exposure to cognitively stimulating materials and experience greater levels of stress.

These insights have important implications for two ongoing areas of interest to me. Firstly, debates about parental virtue and genetic intervention (see these entries). This study clearly shows how rich and poor parents influence the brain development of their children by their exposure (or lack of exposure) to different environments. So parents influence, for good or bad, the biology of their children. Keeping this fact in mind can help us make sense of the ethics of seeking to cultivate phenotypes via direct biological interventions (e.g. genetic or pharmaceutical intervention). In the case of environmental interventions, the goal is not to reduce inequality by preventing rich parents from exposing their children to the environments that promote brain development. Rather the goal is to try to bring disadvantaged children up to this higher level of development.

So the concern at stake here is really prioritarian rather than egalitarian. And those concerned about the impact of poverty on children ought to be interested in the potential benefits that the biomedical sciences (especially research on the brain) could yield. To those who balk at such a suggestion and think tackling poverty itself is much easier, well, this study shows how complex and difficult the challenges really are. In the ideal world every child would be born into an environment where they are exposed to the kinds of stimulations that augment their brains in the ways most conducive to flourishing. But if a pharmaceutical intervention could be prescribed that would mimic the brain development of being exposed to these environmental complexities, would it really be better to forfeit them in the name of achieving brain development via "traditional (yet unequally accessible) means"? It is easy to wave our arms around and say "drugs won't be equally accessible to all" but the same is true of complex environments. Indeed, it is impossible to ensure all receive exposure to the same environments. But a pharmaceutical intervention could help us satisfy a principle of sufficiency for brain development in children. And that would be an incredible accomplishment (and may arrive sooner than you think).

Secondly, this kind of study helps bring precision to what it is about socio-economic inequality that is objectionable. The problem is not that that some people have more money than others; rather, it is that the brains of some children are not exposed to the kinds of complex environments that cause the brain development we believe all children should achieve. How can we best remedy this situation? Rather than just looking to redistributing wealth, we are more likely to see that a wide array of measures are necessary. These range from trying to reduce teenage pregnancy and the demands placed on working parents, to supporting better public education and scientific research on the brain. Humane societies that seek to treat future generations with the care and respect they deserve ought to foster a culture supportive of the family, science and parental virtue.