Poverty marks the brain and damages learning

But the impacts on brain development, genes and chemistry can sometimes be reversed, suggests research
Neil Conway, flickr.com, CC BY 2.0
Neil Conway, flickr.com, CC BY 2.0

There have always been physical marks of poverty that are observable on a child – ragged clothes, rotting teeth and a pale, malnourished look identified the nineteenth century pauper.  Today, we can sometimes see signs in children’s brain development, in how their genes function and in the hormones that circulate in their bodies.

These additional insights are helping to explain what‘s long been recognised ­­­– that children raised in adversity often struggle to stay calm, concentrate and think properly. It is becoming clear that poverty and its stresses can affect biology and body chemistry, which in turn influence behavioural skills, a child’s capacity to learn and, hence, that person’s lifelong prospects.

It’s as if an educational punishment is imposed early in life on some of our youngest, most vulnerable citizens.

These discoveries – that poverty’s stresses can leave a long-term, highly influential, biological imprint on children – seem depressing. It’s as if an educational punishment is imposed early in life on some of our youngest, most vulnerable citizens. However, there are also grounds for hope which are exciting researchers, policy makers and practitioners. It’s expected that at least some of these biological imprints can be averted or, where they do occur, they can be reversed. There is also evidence that, as the biological imprints are successfully tackled, the associated behaviours that damage learning improve in tandem.

“Gray matter” develops more slowly in poorer children

Let’s start with the brain. Latest research shows that the brains of children raised in very poor households (below the US federal poverty line) grow more slowly. They have less “gray matter” in two key areas, according to MRI scans of such children’s brains. The first is the “frontal lobe”, which is important for concentration, complex thinking and staying calm. The second is the ‘temporal lobe’. This matters for memory and language skills.

This slow brain development may account for up to a fifth of the reduced performance by low income children in US tests, compared with well-off children, according to the research co-authors, Dr Nicole L. Hair, University of Michigan and Professor Barbara Wolfe, University of Wisconsin – Madison.

This lagging behind of poorer children is well-documented, so that by the time they reach formal education at age 5 in the US, they are a year behind most of their well-off peers, a difference that is typically never bridged by their subsequent education, according to Professor Greg Duncan of the University of California, Irvine, and co-author of “Restoring Opportunity”.

Poverty impacts on “epigenetic” signals

What about genes? Research by Professor Michael Meaney of McGill University has established that environmental factors, such as parenting styles, can switch some genes on and silence others that influence a person’s stress responses and hence their capacity to learn. These “epigenetic” signals were first identified in the brains of rats that had lacked parental care. The environmentally-induced changes to genes observed in these rats have subsequently also been found in humans. Researchers have performed post-mortem examinations of tissue in the same part of the human brain from individuals known to have experienced maltreatment when they were children.

Next, let’s look at the chemistry of the body. There has been a great deal of research into the operation of cortisol, one of several hormones that can be released when we experience stress. Cortisol is perfectly normal in the human body. It helps us focus on danger and to react quickly. The hormone’s release is often accompanied by a quickened heart rate and sweaty hands. However, research has shown that, when children experience chronic adversity, perhaps through poverty or abuse, they can have abnormally high levels of cortisol, which can make them hyper-reactive and damage their learning skills. Long-term over-dosing of cortisol can also lead to wear and tear on the human body, damage to the immune system and poorer long-term health.

Alternatively, if children have been neglected or denied nurturing, they can have unusually low levels of cortisol, which makes them hypo-reactive, slower than usual to respond to stimulation and learning opportunities, as well as more vulnerable to depression.

This work, looking at the biological and chemical impact of adversity on children, is starting to expand our understanding of the causal links between poverty, behaviour and learning. It’s unlikely to provide all the answers, because we know that some children who experience chronic stress still manage to learn very well. This suggests that, though the epigenetic effects of poverty are important, the differences in inherited genetic make-up make some children more susceptible to poverty’s blows and others more resilient.

Less access to resources explains educational underperformance

Slower learning by some poorer children may simply be down to less access to resources. For example, there is a body of research going back to the 1960s showing that children in low income families typically hear 30 million fewer words by the time they are age 5, compared with their wealthier peers.

This more limited access to the spoken word has long-term implications for reading development and hence access to school-based knowledge, learning and the curriculum. Latest research shows that this poorer language development in low income homes is often compounded in other settings, such as local schools which fail to tackle the “word deficit”.

Another line of research has examined spending by US parents on books, high quality child care, summer camps and schooling for their children. It shows that the difference between low and high income parents’ expenditure on such stimulating activities has tripled in the last four decades. In short, widening inequalities in parental incomes is being mirrored by growing gaps in spending on important developmental activities.

“The good news is that a poor start to learning should not have to mean a life that lacks learning.”

A later blog post will explore some of the approaches that are being advocated to reduce poverty’s impact on learning. Some are system-wide and expensive. Others are less ambitious, but highly effective.

Being able to test for the reversal of biological and chemical markers of poverty should highlight programmes that are most effective. This research should also help practitioners to identify children who are particularly vulnerable to adversity. It will allow support to be more individually tailored to those most in need.

We are on the cusp of understanding the scale and the biological depth of problems for learning that are caused by poverty. But, at the same time, we are beginning to see more precisely how practice and policy could make a big difference with well-targeted, well-evidenced supports. The good news is that a poor start to learning should not have to mean a life that lacks learning.