Poverty affects brain development through attention needs

December, 2012

One reason for the association between poverty and poorer cognition in children may lie in how poverty affects attention, with poor children tending to use more cognitive resources in monitoring the environment.

There have been a number of studies in the past few years showing how poverty affects brain development and function. One of these showed specifically that children of high and low socioeconomic status showed differences in brain wave patterns associated with an auditory selective attention task. This was thought to indicate that the groups were using different mechanisms to carry out the task, with the lower SES children employing extra resources to attend to irrelevant information.

In a follow-up study, 28 young adolescents (12-14 years) from two schools in neighborhoods of different socioeconomic status answered questions about their emotional and motivational state at various points during the day, and provided saliva samples to enable monitoring of cortisol levels. At one point in the afternoon, they also had their brainwaves monitored while they carried out an auditory selective attention task (hearing different sounds played simultaneously into both ears, they were required to press a button as fast as possible when they heard one particular sound).

While performance on the task was the same for both groups, there were, once again, differences in the brain wave patterns. Higher SES children exhibited far larger theta waves in the frontal lobes in response to sounds they attended to than to compared to those they should have ignored, while lower SES children showed much larger theta waves to the unattended sounds than for the attended sounds.

While the lower SES children had higher cortisol levels throughout the school day, like the higher SES children, they showed little change around the task, suggesting neither group was particularly stressed by the task. Both groups also showed similar levels of boredom and motivation.

What the findings suggest is that lower SES children have to exert more cognitive control to avoid attending to irrelevant stimuli than higher SES children — perhaps because they live in more threatening environments.