by Valentina Lagomarsino
figures by Olivia K. Foster Rhoades

Brain development takes a long time. In fact, the human brain isn’t considered fully developed until after 25 years of life! To ultimately develop a healthy brain architecture, the foundation has to be sturdy. Scientists have found that events that happen during childhood are the most indicative of how one’s brain develops. There are many childhood events that can interfere with healthy development, but one thing that unites these deleterious events is that they cause damaging stress to the child’s brain. While children from all backgrounds deal with some harmful circumstances, children in underrepresented communities are often subject to more than their fair share. Racism and discrimination have been shown to cause toxic amounts of stress and affect brain development. Other factors that impede healthy development include violence and the loss of a parent, situations that are exacerbated by police brutality and are disproportionately prevalent in marginalized communities. Thankfully, there is some hope. Research shows that there are ways to mitigate the negative effects of toxic stress on brain development and we must implement policies, based on this research, to help mitigate the effects of stress on the developing brain.

What is ‘toxic stress’ and how does it affect brain development?

During the first few years of life, millions of neural connections are made per second. These connections set the groundwork for different circuits in the brain that underlie learning, awareness, mood, and all kinds of behavior.  One of the largest factors that can alter this normal brain development is stress. Research has shown that intense, frequent, and/or prolonged stress without sufficient support and protection from adults can become toxic, meaning it will negatively affect the way a young brain develops and ultimately alter a child’s mood, ability to learn, and behavior.

Adverse childhood events, including racism, community violence, loss of a parent due to police brutality, poverty, and even the mental state of a child’s parent have been shown to cause toxic stress. Before a child is able to understand the meaning of stress, it could have already left a long-lasting effect on the development of their brain. Ultimately, having a healthy brain is important for one’s mental health, physical health, and overall well-being. While correlative, it’s worth noting that marginalized communities, which are often subjected to more social and environmental stressors, have higher rates of mental health issues and chronic illnesses, like metabolic syndrome and cardiovascular disease. These chronic illnesses may also make people living in marginalized communities more susceptible to infectious diseases such as COVID-19.

The National Scientific Council on the Developing Child has found that early intervention to build resiliency may be able to mitigate the effects of toxic stress on brain development. However, we are currently lacking in policies that address toxic stress at large. Moreover, as a country, we are failing to provide children in marginalized communities with the tools that will give them equal opportunity in life and minimize the effects of adverse childhood events. While many systems need to create policies that address systemic racism and work to combat toxic stress, implementing policies in our education system is crucial for early intervention to reduce toxic stress. After all, school is where the young mind goes to learn and develop.

Not all schools are created equal

In 2010, the California School Board Association filed a lawsuit against the state of California, known as Robles-Wong v. California, with the claim that not all students in the state were receiving the same quality of education. Around that time, another group of concerned students and parents filed a similar lawsuit, Campaign for Quality Education v. California. The major argument in these cases was that “the state was not meeting its obligation to provide all students, regardless of background, with an equitable and high-quality education.” After nearly five years of bouncing around the courts, the California Appeals Court sided with the state, ruling that the California Constitution does not guarantee the right to an adequate level of education, but instead only a “structure of schools,” or a government-funded school in every district that is free to constituents.

The result of this ruling emphasizes the idea of “opportunity by zip code.” Using information from the U.S. Census Bureau and IRS data, researchers from Harvard University and Brown University have put together an Opportunity Atlas. The Opportunity Atlas uses modeling to predict how a child’s zip code, family income, and race can increase their risk for incarceration and poverty later in life. Moreover, researchers at the Harvard School of Public Health have shown that zip code can also predict a person’s overall health across life. Notably, a zip code is also a mandate of which public school a student can attend, and the quality of education they will receive.

Public schools in the U.S. are funded by federal, state, and local sources. This means that there are extreme differences in funding for public school education between states and also within states. Research from the National Center for Education Statistics, analyzing the 2016 fiscal year, found that on average, 36.5% of total revenue for public schools was from local property taxes. This means that schools in zip codes where property taxes are lower (like impoverished neighborhoods) will have less funding. This could equate to a difference of thousands of dollars allocated to each student living in an impoverished neighborhood compared to an upper-middle-class one. Given the scientific evidence that stressors like poverty, racism, and discrimination can cause toxic stress and negatively affect the developing brain, why do public schools in marginalized communities have so much less funding? It is critically important that all students are set up for success in life with equitable school funding and beneficial programming that can act as a buffer to protect students from the harmful effects of toxic stress in their lives.

Another widespread problem in our educational system that exacerbates the effects of toxic stress is the school to prison pipeline. According to the American Civil Liberties Union (ACLU), children living in marginalized communities are frequently “funneled out of public schools and into the juvenile and criminal justice systems.” Since the 1970s, schools across the nation have adopted “zero-tolerance” policies, which means that students of all ages are being suspended from school for minor acts of misconduct. Multiple suspensions can then lead to in-school arrest, juvenile delinquent programs, and eventually to incarceration. Furthermore, this trend has been found to disproportionately affect Black students. The problem with “zero-tolerance” policies is that they do nothing to address the underlying cause of misbehavior and instead focus on punitive measures, adding more stress to an already stressed out child.

Our current education system is failing students in marginalized communities. Scientists have shown that early intervention is imperative to mitigate the negative effects of toxic stress on brain development. We need to use policy to change the educational system, to implement practices that can address toxic stress in schools at a young age and, in turn, improve the well-being of all of our communities.

Where do our policies need to go?

The Center on the Developing Child at Harvard University has come out with a list of policies to reduce toxic stress.  This list includes policies that will strengthen core life skills in young children, such planning, focusing, remembering instructions and jugging tasks. These skills build “executive function and self-regulation,” helping children feel like they have control over the things that are happening around them and, in this way, building resilience. Further, they advocate for policies to increase funding for a higher teacher to student ratio and shift teaching methods away from rewarding extrinsic accomplishments (such as test scores) towards constructive feedback that values effort, creativity and exploration. Lastly, they include policies to ensure that education service workers, such as teachers, social workers, therapists, and school nurses are not overloaded with caseload or by class size, which can cause burnout. Policies that ensure service workers have sufficient compensation, professional development options, and helpful supervision can also help with burnout.

Figure 1: Schematic of intervention policies to address toxic stress. Without intervention, adverse childhood events can result in toxic stress syndrome which reduces connectivity between the neurons that comprise the brain . With educational interventions, it is possible to reduce or limit toxic stress such that the child’s neurons develop normally.

The ACLU and Southern Poverty Law Center have also suggested policies to combat the school to prison pipeline. These include using data to identify the school districts with higher levels of suspension rates and then providing additional support to these schools, by bringing in more social workers and therapists. Additionally, we need policies that provide funding to incorporate programming for positive behavioral interventions, peer mediation, and conflict resolution programs, which have been shown by child psychologists to have a positive effect on behavior. Lastly, checks and balance policies should be in place to investigate unlawful discrimination in schools using punitive measures. 

While many of the suggested policies listed above have not yet been made into law, some politicians are putting this issue high on their lists of things to address. Ayanna Pressley, the representative for Massachusetts’ 7th congressional district, believes “equitable access to high-quality education is vital to addressing inequities in our communities and closing persistent opportunity gaps.” Regardless of other systemic inequities that students face outside of the classroom, better policies in our education system may be able to improve opportunities  for  students to better themselves. Educational policies that have been founded on research to reduce the effects of toxic stress and equitable funding for schools may be able to ensure healthy brain development for all children, regardless of their zip code.


Valentina Lagomarsino is a third-year PhD candidate in the Biological Biomedical Sciences program at Harvard University.

Olivia Foster Rhoades is a fifth-year Ph.D. student in the Biological and Biomedical Sciences program at Harvard & is pursuing a concentration in STS at the Harvard Kennedy School. You can find her on Twitter as @OKFoster.

Special thanks to Laura Lagomarsino, PhD candidate in Educational Leadership for Changing Populations, for her expertise on this subject.

For Future Reading:

This article is part of our special edition on science policy and social justice.

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