A study published last week by Frontiers in Human Neuroscience found that socioeconomic status (SES) correlates with children’s ability to ignore background noise. Researchers compared twenty-eight Canadian students from two schools – one low-income and the other high-income – in their stress (cortisol) levels, attention span (neural activation) and emotional states to study how varying socioeconomic environments affect children’s development, specifically cognitive and emotional responses to background versus relevant noises. They hypothesized that lower SES children would demonstrate higher stress, more adverse emotions and asymmetrical activation in the frontal cortex. To quantify stress, researchers measured cortisol levels, while they used questionnaires to evaluate emotional states and conducted electroencephalogram (EEG) tests to observe cognitive response (event-related potential, or ERP). Before beginning the experiment, children were matched for age, race, hearing acuity and academic achievement. After arriving at school, children provided a saliva sample to establish baseline cortisol levels and then completed the questionnaire to assess baseline levels of boredom, perceived stress, engagement, challenges, fear and other emotional states. Their saliva was then tested six times throughout day to look at changes in cortisol levels, and they completed multiple questionnaires to track changes in emotional state before and after the EEG test.
Children from lower SES backgrounds maintained slightly higher levels of cortisol, but both groups showed a similar rise and fall pattern over the course of the day. No significant differences emerged between groups with the emotion questionnaires. The largest discrepancy between study groups involved cognitive responses. Children from higher SES backgrounds showed more difference in ERP activation, indicating they attended much less to non-target (background) noise than target sounds. High activation in lower SES children trying to ignore tones may demonstrate they pay more attention to background noise, and also require more executive resources when trying to ignore it. Researchers theorize that danger in the lower SES neighborhood may have made it advantageous for those children to attend more heavily to potentially-threatening background noise. Higher SES children from safer neighborhoods would not have had that same environmental pressure. However, small sample size and large individual variation within the samples prevent researchers from making any definitive claims.
In 2010 the Schubert Center hosted a talk with Nobel Laureate James Heckman, PhD where he spoke on the Heckman Equation, which encourages investment in early childhood development to reap economic returns over time. His research shows that developmental contact with disadvantaged populations before age five would help lessen socioeconomic disparities and increase children’s ability (and desire) to contribute to society as they grow older. For more information, watch his presentation or read his slides online. The Schubert Center is hosting an event on March 21, 2013 titled The Long Reach of Child Poverty, featuring Ariel Kalil, PhD, who will discuss explanations for disparate academic achievement, “problem” behaviors and health outcomes among impoverished children. Learn more about the upcoming talk here.