Conducted at the University of California, Berkeley, the study involved 26 children in the age group of nine to ten years. Half of them were from low-income homes, while half from high-income families.
The researchers used an electroencephalograph (EEG) to measure activity in the "prefrontal cortex" of the children's brains.
During the test, the children were shown an image onto a screen. They had not been briefed about the picture.
The researchers measured the subjects' brain responses as they saw the picture.
They found that children from lower income families showed a lower prefrontal cortex response to it than those from wealthier households.
"The low socio-economic kids were not detecting or processing the visual stimuli as well - they were not getting that extra boost from the prefrontal cortex," the BBC quoted Dr. Mark Kishiyama, one of the researchers, as saying.
Given that the subjects were normal in every way, the researchers believe that the "stressful environments" created by low socio-economic status might be the reason behind different brain responses between the two groups.
The researchers also referred to past studies that showed that children in low-income families were spoken to far less, on average hearing 30 million fewer words by the age of four.
Professor Thomas Boyce, another member of the research team, said that talking more to children could help boost prefrontal cortex development.
"We are certainly not blaming lower socioeconomic families for not talking to their kids - there are probably a zillion reasons why that happens," he said.
His colleague, Professor Robert Knight, added: "This is a wake-up call - it's not just that these kids are poor and more likely to have health problems, but they might actually not be getting full brain development from the stressful and relatively impoverished environment associated with low socio-economic status."
He believed that it was possible to achieve improvements, even in older children, through "proper intervention and training".
Dr Emese Nagy, from the University of Dundee, called it a "pioneering" study saying that it could help deeply understand how environment could affect brain development.
She said: "Children who grow up in a different environment may have very different early experiences, and may process information differently than children from a different environment."
She added: "The study showed that low socio-economic status children behaved exactly the same way as high socio-economic status children, but their brain processed the information differently."