A six-year study by researchers at the University of Wisconsin-Madison has added to the mounting evidence that growing up in severe poverty affects how children’s brains develop, potentially putting them at a lifelong disadvantage.

The study – which combined the expertise of neuroscientists and economists – found that parts of the brain tied to academic performance were 8 percent to 10 percent smaller for children who grow up in very poor households.

It was based on a relatively large sample of predominantly white children whose mothers were much more educated than the general population. And the results show a biological link between growing up in extreme poverty and how well children do academically.

“The significance of the study is providing a hard physical link between the experience of growing up in poverty and how well children do on cognitive tests,” said Barbara “Bobbi” Wolfe, an economist at UW-Madison and one of the co-authors of the study.

The study, published in JAMA Pediatrics, builds on animal studies and other research suggesting that poverty affects parts of the brain tied to self-control, attention, planning and other traits important for success in school and life.

The children often receive less nurturing from parents and live in environments characterized by increased stress from crowded housing, instability, poor nutrition, limited stimulation and more exposure to violence.

That children who grow up in poverty do less well in school is well documented. But studies increasingly show that at least part of that overall poor performance stems from how their brains grow and work.

The UW study estimated that as much as 20 percent of the gap in test scores could be explained by slower development of two parts of the brain: the frontal lobe and the temporal lobe.

The frontal lobe is important for controlling attention, inhibition, emotions and complex learning. The temporal lobe is important for memory and language comprehension, such as identifying and attaching meaning to words. Both areas of the brain develop through adolescence.

“It provides a brain-based explanation for why children living in poverty are not performing academically as well,” said Joan Luby, a professor of child psychiatry and director of the Early Emotional Development Program at Washington University School of Medicine. The UW-Madison study was led by Wolfe and Seth Pollak, a professor of psychology and director of the Child Emotion Lab.