Suzanne Houston
Source: Suzanne Houston

This guest post was written by Suzanne Houston, a doctoral candidate in developmental psychology at USC who uses neuroimaging techniques to study brain development in children and adolescents.

All of you reading this sentence have been adolescents at one point.  You have experienced the years marked by self-consciousness and peer pressure; when your parents were too strict, and your teachers too annoying.  Somehow, you managed to struggle through it all to read this post.  Perhaps some of you have teenagers of our own.  Now, you are the strict parent, the annoying teacher. You are the one knocking on bedroom doors because you smell cigarette smoke, or the music is too loud. Perhaps, you are hiding the car keys, because you want to keep your child safe and under your roof, far away from the statistic that says that mortality rates among adolescents increases by 200%, among adolescents who drive compared to those who do not. 

Now add poverty to the mix. According to the National Center for Children in Poverty (NCCP), roughly 16 million children and teenagers in the United States—1 in every 5—live below the federal poverty line. The percentage of adolescents (age 12-17) living in families with low income increased from 35% in 2007 to roughly 41% in 2013.  Nineteen percent of this age group live below the poverty line. 

 Tyrone Daryl, Creative Commons license
Source: Tyrone Daryl, Creative Commons license

Socioeconomic status (SES) has been linked to significant differences in social, emotional and language processing. Indeed, two decades of research has indicated that teenagers from lower socioeconomic backgrounds demonstrate lower academic achievement, are more likely to suffer from anxiety and depression, and are more likely to drop out of school and experience more family and parental discord. Given that adolescence is already known to be a time of increased rebellion and risk, how can we keep low-SES adolescents from falling through the cracks at school?

The teenage brain has been the subject of speculation for centuries. Aristotle once said that youth are “as heated by Nature as drunken men by wine,” and Socrates observed that adolescents “contradict their parents and tyrannize their teachers.”

Recent studies have debunked some myths about the teenage brain, such as the idea that the “storm and stress” of adolescence is universal, or purely biological, or that adolescents cannot make rational decisions. Specifically, studies have focused on the misperception that teenagers make poor decisions due to the immaturity of the prefrontal cortex, the part of the brain linked with cognitive control and executive functioning.

In one such study, interesting developmental patterns emerged in regards to self-control for emotionally salient versus non-emotionally-salient stimuli, particularly in males. Specifically, with no emotional information present, adolescents can perform as well as adults on self-control tasks, which suggests that it is not the prefrontal cortex that is underdeveloped, but rather the systems related to emotional processing (Tottenham, Hare & Casey, 2011).  In short, teenagers are not completely incapable of making optimal and rational decisions, but emotionally salient stimuli may make it harder for them. What IS changing during adolescence are the pathways that connect the prefrontal cortex to regions that are responsible for motivation, emotion and reward processing. In addition, research has suggested that the notion that all adolescents experience the same amount or degree of storm and stress seems stereotypical at best, since things like home environment and social relationships can also shape adolescent development.

If even some typically developing teenagers experience emotional volatility, what might happen to teens living in poverty? These teens are likely to be exposed to more neighborhood violence, go to subpar schools, and experience more chronic stress and unpredictability.

Recent neuroimaging studies from my laboratory have studied the relationship between poverty and brain development. In a cross-sectional study of sixty children ages 5-17, we observed differences in brain volume (one component of brain size), in the amygdala and hippocampus, widely regarded to be responsible for emotion/salience processing and memory, respectively. Participants whose primary caregivers had received less education had larger amygdala volumes, while lower family income was associated with smaller hippocampal volume. As children got older, SES variables seemed to have more an effect on regions responsible for language, suggesting that differences in a child’s emotional environment and linguistic exposure may account for differences in brain structure.  A larger study from our lab studied 1,099 children ages 3-21 and we reported differences in surface area as a function of family SES. We found that lower family income was associated with less cortical surface area. This relationship was particularly strong among children at the lower end of the SES spectrum, and in areas that support language, emotional functioning and impulse control

Gerd Altmann, Creative Commons license
Source: Gerd Altmann, Creative Commons license

Still, hope is not lost for teenagers from disadvantaged backgrounds. Numerous imaging studies over the last two decades have established that the developing brain is extremely plastic, or changeable. Therefore, the trajectory of development can be reshaped in positive ways that can last into the teenage years.  We know that by age six, the brain is at 95% of its peak volume—but how those brain regions are learning to communicate are still malleable early on. In fact, even adults show some capacity for plasticity in later life.

So what does this mean for policy initiatives to help teens in poverty? For one thing, more funding could be provided for after school programs and in home interventions that teach parents the benefits of reading to kids and interacting in constructive activities. Given a plethora of research regarding the plasticity of the brain, policies could be developed that target children from lower SES backgrounds early on, in hopes of altering the developmental trajectories in brain areas involved in impulse control, language, and decision-making.  Warmer, nurturing environments are known to be better in the long-term for the developing brain. Therefore, initiatives to support early parent-child attachment could be particularly valuable. For example, better-funded maternity and paternity leave programs for low-SES parents might give parents and infants more time to bond and reduce stress on the family. Funding for childcare programs in low-income neighborhoods would help reduce parent-teacher ratios and provide kids with more enriched early education. In the adolescent years, anti-bullying initiatives and programs that focus on socioemotional intelligence can be incorporated into high school curricula.

Of course, there is a lot more work to be done on SES and the teenage brain.  We do know that SES has different correlates, such as geographical location (Do poorer families live in more polluted areas? Are they spending the money they do have on clothing or nutrition?  Does low-SES increase the risk of community violence and the chronic stress that may come with living in a difficult neighborhood?). Studies that investigate these factors are underway, but the in meantime, it would do us all good to think about how the teenage brain is very much “under construction” and malleable, and that we may be able to implement policies that level the playing field for teenagers from economically and emotionally diverse backgrounds.

References

Arnett, J.J., (1999).  Adodlescent Storm and Stress Reconsidered. American      Psychologist. 54(5). 317-326. 

Casey, B.J. & Caudle K., (2013).  The Teenage Brain: Self Control. Psychological Science. 22(2), 82-87. 

Giedd, J. (2004).  Structural magnetic Resonance Imaging of the adolescent brain. Annals of the New York Academy of Sciences. 1021 (1). 77-85

McLoyd, V.C. (1998). Socioeconomic disadvantage and child development.         American Psychologist, 53 (2), 185–204.

Noble, K.G., Houston, S.M., Kan, E., Sowell, E.R. (2012). Neural Correlates of                 socioeconomic status in the developing human brain. Developmental Science, 15(4) 516-527.

Noble, K.G., Houston, S.M., et al. (2015).  Family Income, Parental education and brain structure in children and adolescents. Nature Neuroscience. 18(5) 773-780.

Steinberg, L. (2015).  How to Improve the Health of American Adolescents.          Perspectives on Psychological Science. 10(6), 711-715. 

Tottenham, N., Hare, T. A., & Casey, B. J. (2011). Behavioral assessment of emotion discrimination, emotion regulation, and cognitive control in childhood, adolescence, and adulthood. Frontiers in Psychology. 2, 39. 

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