New research shows that kids from low-income families may be falling behind their peers because an important part of their brains is underdeveloped. Researchers from MIT' s McGovern Institute for Brain Research compared the brains of 12-and 13-year-olds from rich families with the brains of their peers from lower-income families. They found that one particular area of the brain--the neocortex ,which plays a key role in memory and learning ability--is thinner in children from lower-income households. This is a _ part of the brain for young students, who are often tested based on their ability to recall large chunks of information. Children who had a thinner neocortex performed poorly on standardized tests,researchers found.More than 90% of high-income students scored above average on a statewide math and English/Language Arts standardized test,compared with less than 60% of low-income students.Differences in cortical  thickness could account for almost half of the income-achievement gap in this sample,researchers wrote. "Just as you would expect, there' s a real cost not living in a supportive environment. We can see it not only in test scores,in educational attainment,but within the brains of these children,"says psychological scientist John Gabrieli,a professor of brain and cognitive sciences at MIT and one of the study's authors. Since a 2011 study published by Stanford University professor Sean Reardon found that the gap between standardized test scores of high-income and low-income students has grown by about 40% since the 1960s,there' s been a lot of research aimed at finding links between income and achievement, rather than race alone. The MIT study found low-income children were equally likely to have a thinner neocortex,no matter their races. Gabrieli and his co-authors can' t say exactly why poor children' s brains develop differently because there are too many possibilities to count.Their findings do,however,underline the importance of early intervention  to ensure that low-income kids get the tools they need to succeed. What is the main idea of the passage?
Wealthy parents do better in raising children. Differences exist between poor children and rich ones. Poor children study harder due to their financial conditions. Poor children have thinner neocortex than their wealthy peers.