Inequality, Children, and Brain Development - Event Recap
December 05, 2017
On Tuesday December 5th, the Penn Wharton Public Policy Initiative and the Wharton Neuroscience Initiative co-sponsored a talk by Dr. Kimberly G. Noble (C’98 GR’05 M’07), Associate Professor of Neuroscience and Education at Teachers College, Columbia University. Trained as a neuroscientist and pediatrician, Professor Noble studies how inequality relates to children’s cognitive and brain development across infancy, childhood and adolescence. Her research is focused on the study of neurologic development in children under 3 years old, the socioeconomic factors that correlate with brain development disparity, and the ways we might harness this research to inform the design of public policy interventions.
Early Childhood and Brain Development
In order to understand the significance of early childhood experiences on long-term cognitive function, one needs to have a basic knowledge about how the brain develops in infancy. “The human brain has been termed the most complex three pounds in the universe, and it is not hard to see why,” Noble began. “We are born with 100 billion neurons and in every minute of the first few months of life we develop between 200,000 and 250,000 new brain cells,” she said. It is not just the number of cells that are so significant, but it is the connections between these cells that are significant. By age three, humans have one thousand trillion connections between synapses in these cells. Even more interestingly, childhood experiences shape the development of these connections. The brain is most plastic, or able to make these connections, early in childhood. A child’s experience is very much a function of his or her social or economic circumstances, so we can use these socioeconomic factors as a lens through which we can better understand brain plasticity.
Poverty and Socioeconomic Status
Poverty is an income level defined by the federal government. The current poverty line for a family of two adults and two children is $24,000. This level varies by family size but remains constant geographically. “A family of four in Philadelphia has the same poverty line as a family of four in rural South Dakota, even though clearly the cost of living is very different in those two places,” Noble noted. Poverty has been shown to put children at risk for a host of negative physical health, mental health, and achievement outcomes. Sadly, one in five children live below the poverty line, and this number doubles when looking at children living just above the poverty line.
Socioeconomic status (SES), however, encompasses more than just income - it also includes parent’s educational achievement, occupational prestige and subjective social status. The socioeconomic gap between children emerges early, and widens over the years, Noble said, citing a 1970’s study by the British Cohort looking at cognitive performance in children 2-10 years of age with different socioeconomic status. Children coming from socioeconomically advantaged backgrounds were able to increase their achievement relative to their peers, whereas children with disadvantaged backgrounds typically dropped in achievement, even if they were as high or higher achieving as their advantaged peers at the start of the study. Thus, the differences in socioeconomic status significantly impacts children and their achievement. The reasons for these differences is attributed to variations in nutrition, healthcare, drug exposure, exposure to environmental toxicants like second hand smoke or lead, home living environment, early schooling, family stress, and more. Each of these factors has been shown to contribute, in part, to the link between socioeconomic disparities and children’s cognitive skill.
In order to gain greater clarity about what the relationship is between SES and cognitive skill, Noble explained that neuroscience can be used to examine what specific cognitive skills are most associated with SES. “Neuroscience teaches us that different brain structures support different kinds of cognitive skills, like language, memory, and facial recognition skills, to name a few,” she said. Neuroscience is a tool that enables researchers to examine specific areas in brain circuitry affected by socioeconomic factors. Her former research looked at which cognitive functions are most impacted by SES, how brain structures correlate with SES, and finally, at what age these differences are detectable. For instance, children of more highly educated parents were shown to have better language skills and better memory skills by age 21 months.
Importance of Early Intervention
The findings of Professor Nobles’ research can help inform the conversation around effective interventions. Certainly, school based interventions are the most common, however they tend to be labor intensive, costly, and suffer from fade out. Though this does not suggest that school based interventions are not worthwhile, it does suggest that other less costly interventions should act as a supplement. Also, Noble argues that waiting until children reach school is arguably waiting too long - by the time that children are two, significant differences already emerge across socioeconomic classes. Parenting intervention may be a useful tool to mitigate these differences early on, however attrition and engagement are difficult to cope with. Home based interventions are more difficult to scale up, posing further challenges.
Noble suggests changing socioeconomic status itself. “Small income boosts have been shown to have big effects,” she said, citing a study which showed that a $4,000 increase in annual family income with children between the prenatal year and year two. This small difference resulted in a 19% increase in earnings for these children when they became adults and evidence of improved health. Noble seeks to expand the investigation of these effects in her participation in a new study that recruits 1,000 poor mothers across the country who will receive a cash transfer to spend however they like over the first 40 months of their child’s lives. One group will receive a larger sum of $4000 per year, while the other group will receive $240 per year. Noble will then be able to study the causal impacts on brain development of poverty reduction in the first three years of life. Her team of researchers has two working hypothesis. That either the money will be used to provide better quality childcare, more books and toys, and more stimulating activities, or the money will help to reduce family stress, a negative factor on childhood development.
Noble ended her talk thanking Penn Wharton PPI and the Wharton Neuroscience Initiative for their sponsorship, in addition to audience questions.