Brain scans of children and young adults have revealed that specific brain regions tend to be smaller in those from poorer backgrounds than those born into wealthier families.

The effects were most striking among the poorest families who took part in the study, where even modest changes in wages could have a significant impact on the structure of the children’s brains.

The brain regions involved are crucial for the development of language, memory and reasoning skills, making them central to a child’s potential to thrive at school and gain a good education.

Scientists hope that the findings will help to drive fresh interventions to boost brain growth in children who need it most. They could include targeted activities at school and at home; easier access to further education, which often leads to higher incomes; or simply more generous benefits for the poorest families.

“The brain is the product of both genetics and experience, and experience is particularly powerful in molding brain development in childhood,” said Kim Noble, first author on the study at Columbia University in New York. “Interventions to improve socioeconomic circumstances, family life, and educational opportunities can make a vast difference.”

The researchers scanned the brains of more than 1000 children aged three to 20 years old and, after taking genetic factors into account, found that the surface area of the children’s cerebral cortex tended to expand as family income rose. The surface area of the cerebral cortex was typically 6% larger in children from familes with an income greater than $150,000 (£101,000), when compared to families earning $25,000 (£17,000) or less.

The parents’ education had an impact on their children’s brain structure too, with scans revealing a larger hippocampus in children from more educated families. The hippocampus plays a pivotal role in short term memory and spatial navigation.

The study, published in Nature Neuroscience, cannot say categorically what causes the brain changes, but the scientists behind the research believe they reflect differences in the environment in which the children’s brains develop. A multitude of factors likely come into play: the children may experience more stress, live in more polluted areas, have less cognitive stimulation in their daily lives, be spoken to less, and their mothers may have had poorer diets while pregnant.

“Families who have financial difficulties tend to have much more stress in their lives. Decisions need to be made on how to spend on how to spend limited resources, such as food and shelter might not always be guaranteed in those with the lowest incomes. So the quality of life for a family with an income of $50,000 (£34,000) might be much less stressful than a family with an income of $30,000 (£20,300),” said Elizabeth Sowell, a senior author on the study and director of the developmental cognitive neuroimaging lab at Children’s Hospital, Los Angeles.

But she added: “The message is not ‘if you are poor, your brain will be smaller, and there is nothing that can be done about it’. That is absolutely not the message. Improving access to resources that enrich the developmental environment could potentially change the trajectories of brain development for the better, even in children and adolescents in the age range we studied.”

Michael Thomas, director of the Birkbeck-UCL Centre for Educational Neuroscience, said the study could help researchers tease out more precisely how a low income might affect children’s brains. “If we find that all these factors are equally responsible, that is prenatal health, stress levels, nutrition and cognitive stimulation, the only way to fix the issue is to get rid of poverty, and that’s a hard thing to do. But if we can narrow it down, to some factors that are particularly influential in causing problems for the kids, that makes it more possible to intervene,” he said.

Noble’s lab at Columbia is now planning a major trial to investigate whether giving monthly payments to the poorest families boosts the brain development of their children, by alleviating some of the factors that hamper it. Under the trial, a group of low income mothers from across the US will receive either a large monthly sum, or a modest payment, to see whether the money makes any difference to their lives. Noble says the results will directly inform public policy on the generosity of benefits to low income families with young children.