POOR KIDS tend to fare badly at school. Rich children tend to do better. Poverty seems to run, like an oppressive thread, through the generations. Affluence also knits generations together, although that thread has a silkier sheen. No great revelation, this. But one thesis about why poverty is so often paired with low intellectual attainment could prove seismic. Martha Farah, the director of the Centre for Cognitive Neuroscience at the University of Pennsylvania, has raised the possibility that a deprived childhood may affect the physical development of the brain and render its owner less intellectually capable. For this reason, Professor Farah says, poverty deserves to be considered alongside such behaviour-altering drugs as Ritalin as an agent that can change the fundamentals of who you are.

To go a step further. If poverty wrecks the brain, then it is plausible that, generally, poor people make “worse” decisions than rich people. And if they do, do they bear the same level of responsibility for their actions? Is it fair, say, for the NHS to blame cancer-ridden smokers and obese burger-munchers — both disproportionately represented among the impoverished — for their condition?

Farah became interested in the link between socioeconomic status (SES) and children’s cognitive achievement when she started employing baby-sitters, who tended to be poorer and less educated than herself. “Their daughters and sons and nieces and nephews began life with the same evident promise as my daughter and her friends,” Farah writes in the book Neuroethics (OUP). “Yet as the years went on, I saw their paths diverge.”

While the children on Farah’s side of the tracks learnt how to read newspaper headlines, the kids on the other side showed a “sad precocity” with grittier topics — jail, the sound of gunshots. “It seemed to me that children’s experience of the world is very different in low and middle SES environments,” Farah noted. This led Farah to do some experiments testing cognitive functions — language, memory and visual processing — in children of low and middle SES. She discovered that the “most robust neurocognitive correlates of SES” were language, memory and cognitive control (such as planning tricky tasks). In other words, low SES children consistently performed worse than middle SES children on tests involving memory, language and task-planning. It is not hard to see how this results in a less starry future.

It could be the case, of course, that instead of poverty wrecking the brain, a pre-wrecked brain perpetuates poverty. Twin studies in low SES families suggest that IQ — an imperfect but useful gauge of intellectual ability — is at least as, if not more, dependent on environment as on genetics.

Interestingly, another study indicates that even brief periods of poverty can harm a child’s cognitive development. Younger siblings are hit harder, suggesting that poverty exerts real influence on early mental development.

Further, all the other problems associated with an underprivileged life — iron deficiency, malnutrition, exposure to lead (in peeling paint), mothers who take drugs, smoke and drink during pregnancy — all lower school achievement, as do a lack of toys and books. These strengthen the idea that a poor (in every sense) environment dulls the brain.

Now, consider that those in good financial health enjoy better physical health — and longer lives — than those lower down the social pecking order. It is not far-fetched to believe that any physiological processes underpinning this disparity may also give rise to differences in the brain.

In which case, poverty harms children in a very concrete way — by altering their brains. Professor Farah concludes that “neuroscience may recast the disadvantages of childhood poverty as a bioethical issue rather than merely one of economic opportunity”.

• BEWARE THE DREAM employee who is prepared to work nights and weekends, on his own and with no extra pay. He could be an animal rights activist trying to infiltrate a laboratory.

  Advice such as this will be on offer at the annual meeting of the American Association for Laboratory Animal Science, taking place next week in Utah. The highlight, alas, is likely to be an FBI masterclass on personal safety for scientists.

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