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Last month, artists and academics across the country took part in Brain Science Awareness Week, hosting events that celebrated the wealth of applications neuroscience has in daily life. At Sarah Lawrence College, one speaker tackled a question that concerns millions of children, their parents, and the rest of us: the connection between inequality and the developing brain. After her lively, informative talk, Kimberly Noble, an Associate Professor of Neuroscience and Education at Teachers College, Columbia University, spoke with me about how different socioeconomic conditions are tied to the development of language, cognition, and even memory. —Michaela Brady
Could you tell me about your current clinical trial?
I'm collaborating with a group of social scientists and neuroscientists on this study: Greg Duncan, an economist at University of California, Irvine, Katherine Magnuson, a developmental scientist from the University of Wisconsin–Madison, Hirokazu Yoshikawa, a developmental psychologist from New York University, and Lisa Gennetian, an economist from NYU, along with a team of neuroscientists from around the country. The ambition for this study is large, although the premise is pretty simple. Our goal is to recruit 1,000 low-income mothers from four sites nationally and randomize one half to receive a large monthly income supplement and the other half to receive a nominal monthly income supplement. Then we'll track the effect of this unconditional cash on children's cognitive, emotional, and brain development in the first three years, when we know the developing brain is most malleable to experience.
In your presentation, you showed a time plot that tracked cognitive progress over 9, 15, and 21 months among children from high, medium, and low socioeconomic backgrounds. The children from the medium and low groups had lower cognitive measures even before 21 months. What can we infer from this?
Behavioral work from our lab suggests that we can see pretty dramatic differences in language and memory development by 21 months of age, before children even turn 2 years old. It's our hope that by easing some of the financial burdens of these families, we'll be able to change those trajectories in a beneficial way.
You also mentioned family stress is associated with reduced hippocampal volume, which has implications for memory. Can you expand on that?
Well, we know from animal and human studies that exposure to stress can lead to a smaller hippocampus, so we reasoned that perhaps we would see income differences reflected in the size of the hippocampus as well, particularly since we had already seen socioeconomic differences in memory. There are now four independent labs who have reported the same thing—that lower income is associated with a smaller hippocampal size in children. So it's the most well-replicated finding in the field of socioeconomic status and memory.
How about social mobility? Does a child whose socioeconomic status improves demonstrate better academic and cognitive abilities?
The work hasn't really been done from a neuroscience perspective, so we don't have a good sense of what social mobility does to the brain. But we know from the work of people like Greg Duncan and Jeanne Brooks-Gunn that early childhood adversity is associated with more detrimental outcomes than is later childhood adversity, even controlling for the amount of adversity.
Do you think improving one’s situation could rehabilitate the hippocampus?
It's our hope and belief that many of these changes are preventable, even reversible, because of the plasticity of the brain, so that would certainly be a hypothesis worth investigating.
You mentioned you had yet to examine potential effects of media exposure on children in various socioeconomic circumstances. What would you predict the impact of media exposure would be?
A good deal of work has suggested that children learn less well from 2D representations than from 3D, so they are not very good at learning language or other things from 2D representations. So we know that, in general, screens are not going to promote learning as well as real-life interactions. That said, context does matter, so if a parent is watching TV or media with the child and explaining it, that can actually be much more beneficial. And so the question I think will have to do with the context. Is the parent engaged with the child during media exposure or not?
What are your thoughts about future work beyond the clinical trial?
We are still raising funds for the clinical trial, but if our hypotheses are borne out, hopefully we'll be able to follow these families longitudinally and through adolescence. It's also our hope that results could inform debates about policies that affect disadvantaged children.
I want to thank Kimberly for taking the time to discuss her research with me, and I look forward to reading about the outcomes of her clinical trial.
