Living with neighbourhood violence may literally shape teenagers’ brains

Protesters against gang violence in South Central Los Angeles, 2011. Image: Getty.

Flinching as a gunshot whizzes past your window. Covering your ears when a police car races down your street, sirens blaring. Walking past a drug deal on your block or a beating at your school.

For kids living in picket-fence suburbia, these experiences might be rare. But for their peers in urban poverty, they are all too commonplace. More than half of children and adolescents living in American cities have experienced some form of community violence – acts of disturbance or crime, such as drug use, beatings, shootings, stabbings and break-ins, within their neighbourhoods or schools.

Researchers know from decades of work that exposure to community violence can lead to emotional, social and cognitive problems. Kids might have difficulty regulating emotions, paying attention or concentrating at school. Over time, kids living with the stress of community violence may become less engaged in school, withdraw from friends or show symptoms of post-traumatic stress, like irritability and intrusive thoughts. In short, living in an unsafe community can have a corrosive effect on child development.

Few studies, though, have specifically looked at the toll community violence may take on the growing brain. Recently, I studied this question in collaboration with a team of researchers here at the University of Southern California. Our goal: to see whether individuals exposed to more community violence in their early teen years would show differences in the structure and function of their brains in late adolescence.

Witnessing crime has lots of downstream effects. Image: ATOMIC Hot Links/creative commons.

Connecting community violence to the brain

My colleague Gayla Margolin, an expert on youth exposure to violence, has been following a sample of Los Angeles-area youth for over a decade. When these teens were about 13 years old, she asked them to fill out a checklist of community violence experiences: hearing gun shots, witnessing a beating, seeing someone do drugs, watching someone get arrested or chased by the police, seeing someone get chased by a gang, or seeing someone get threatened with a beating or stabbing. For our current study, we added these items together to get an overall sense of how much violence each teen had witnessed in his or her neighbourhood.

About four years after they took the community violence survey, when the youth were around 17 years old, we asked 22 of them to lie down in a magnetic resonance imaging (MRI) machine while we scanned their brains. When we examined the images we’d collected, we zeroed in on two small but critically important structures near the base of the brain: the hippocampus and the amygdala.

The hippocampus, a curved structure shaped like the seahorse it is named after, plays a role in learning and memory. Stress hormones seem to shrink this structure, and adverse childhood experiences like abuse and neglect have been linked with smaller hippocampal volumes later in life. One recent review of research on child maltreatment found that early abuse and neglect predicted smaller hippocampal size in 30 out of 37 studies that looked at the connection.


In our current study, we also measured the size of the amygdala, an almond-shaped structure located close to the hippocampus that is known for its involvement in emotion and threat-related processing. Childhood adversity has also been tied to the size of the amygdala, although this research has been mixed: Some studies have found that people exposed to early stress show smaller amygdala volumes, some show larger amygdalae and some show no relationship at all.

In addition to looking at the size of the hippocampus and amygdala, we also looked at patterns of interconnection between these structures and other regions of the brain. Which parts of the brain “talked” more to each other, as reflected by more tightly correlated levels of activation?

A neural signature of community violence?

In our data, we found that witnessing violence in early adolescence predicted smaller volumes of both the hippocampus and amygdala in this group of teens.

We didn’t measure the absolute size of these structures – instead we tested the relationship between community violence and brain volume. In other words, if our participants told us at around age 13 that their neighbourhood were higher in crime and violence, the size of these critical brain structures looked smaller about four years later, compared to teens who reported less community violence. Interestingly, this link held up even after we controlled for the youth’s socioeconomic status (family income and education) and their present-day exposure to community violence.

These brain regions showed stronger connectivity with the hippocampus among youth exposed to greater community violence. Image: Darby Saxbe/creative commons.

We also found that, among youth exposed to more community violence, the right hippocampus showed stronger connections with other brain regions linked to emotion processing and stress, perhaps suggesting that these youth were more vigilant to potential threat. If you’re used to encountering dangerous situations, maybe you and your brain learn to stay alert to avoid the next potential threat that lurks around the corner.

Our study dovetails with other research on early stress and the brain but is the first to specifically look at the link between community violence and the size and connectivity of the hippocampus and amygdala. Our sample was quite small and limited by the fact that we scanned the youth only once, in late adolescence. Therefore, although our measure of community violence was collected about four years before the scan, we have no way of knowing for sure whether community violence actually led to changes in the hippocampus and amygdala. It’s possible these brain differences preceded the youths’ exposure to community violence. For these reasons, this study should be considered preliminary and needs to be corroborated by much more research.

Despite its limitations, this work takes a first step in showing that community violence is linked with detectable differences in the teen brain in ways that are consistent with other forms of early adversity like abuse and neglect. These effects might be due to stress hormones that flood the developing brain and affect the growth of neural structures like the hippocampus and amygdala.


Youth with smaller hippocampal volumes may show learning and cognitive difficulties, whereas smaller amygdala volumes have been linked with depression risk and behavior problems. In other words, if, as we suspect, community violence has a toxic effect on the brain, downstream effects may emerge both at school and at home. And those effects converge with the deficits in attention, cognition and emotion regulation that other researchers have already noted in youth exposed to community violence. They may even endure into adulthood and contribute to a cascade of risk for further problems in employment and education.

Although community violence may be widespread, that doesn’t mean it’s acceptable. Developing kids and teens deserve to feel safe at home, in their schools and in their neighbourhoods. As our results and those of many other studies show, growing up in a violent or chaotic environment seems to leave traces on the brain, and may put youth at risk for other problems down the line. Although we don’t usually think of street lights, after-school programs and revitalised park spaces as brain-building improvements, public investment in urban neighbourhood safety and quality may have wide-ranging benefits for teens at risk.

Darby Saxbe, Assistant Professor of Psychology, University of Southern California – Dornsife College of Letters, Arts and Sciences.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

How the rise of anti-crime politics caused lasting harm to Black Americans

"I see an awareness that has developed in the Black community in the last 10 years or so about how deeply racist the criminal justice system has become," James Forman Jr. says. (David McNew/Getty Images)

The police killing of George Floyd, and the protest movement that emerged from it, has reinvigorated a national conversation around reinventing criminal justice policy in the United States.

At the same time, reports that violent crime is rising in many US cities have resurrected talk of the much-disputed “Ferguson effect,” a theory put forward by law enforcement professionals, and some researchers, who argued that police slowdowns in the wake of the first wave of Black Lives Matter protests resulted in elevated rates of violent crime. President Donald Trump is trying to weaponise this narrative, paired with images of federal officers clashing with protesters in the streets of Portland, to wage a 1968-style backlash election campaign.

“People who want to mobilise a lock-them-up style of either policing or prosecution have tried to weaponise those short-term increases,” says James Forman Jr., professor of law at Yale Law School. “Criminologists will say you have to be very, very cautious about short-term movement [in crime statistics]. We don't know whether or not what we're seeing right now [with violent crime increasing] is going to sustain itself. But the fact is, it's here and people are talking about it.”

In 2018, Forman won the Pulitzer Prize in nonfiction for his book Locking Up Our Own: Crime and Punishment in Black America. Drawing on his experience as a public defender in Washington, DC, he traced the emergence of anti-crime politics in late 20th century Black communities. Forman showed how newly empowered Black politicians fought for policies they believed would protect and uplift Black Americans, but inadvertently contributed to mass incarceration. 


CityMetric recently caught up with Forman to discuss crime trends, where he sees reason for hope in this moment and how the Black political class’s attitude toward crime and punishment has shifted since the latter part of the 20th century. 

This interview has been edited and condensed. 

There is talk right now about a resurgence of crime and violence in American cities. We saw similar, more localised concerns after the initial 2015 Black Lives Matter protests in Ferguson and Baltimore. Do you fear this could reinvigorate the kind of politics you describe in your book among segments of the Black community and political class?

I fear that it could be reinvigorated nationally and also in the Black political class. Look at the political conversations that are happening in Atlanta right now, for example, a city that also has seen a short-term uptick in crime as it is a site of a lot of protests about George Floyd and Breonna Taylor on the national level, as well as Rayshard Brooks and Ahmaud Arbery more locally in Georgia.

I think that you can already see in some of the language of the local elected officials this idea that we have to be very careful about pulling back. [They are saying] “while the protesters may make some valid points, we can't risk returning to the ‘80s and ‘90s.” Those decades really traumatised the United States, and particularly traumatised Black communities. There's a deep fear about returning to the levels of the violence that we saw in the crack years.

You write a lot about class divides among Black Americans, where middle income and elite Black people don't suffer as much from extremely punitive policies. They also have closer ties to the politicians who are creating these policies. There are very specific groups of people, even in marginalised communities, whose voices are heard.  As a result of these dynamics, you write about Black politicians fighting for things like mandatory minimum prison sentences or against decriminalising marijuana. Is there still that disconnect between those who suffer the most from criminal justice policies and those who are actually heard in political discourse?  

Let me just say a caveat, that when we talk about class divisions in the Black community it's important to hold two truths in our head at the same time. Bruce Western and others have shown the way in which class, educational status, income can dramatically reduce the likelihood of being hardest hit by the criminal system – namely incarcerated. Middle class and upper middle class Black people get some measure of protection. It's also true at the same time that Black people of all classes are worse off relative to their class counterparts in the white community. 

One area where class is least protective is policing and police stops. The police do not know how many degrees you have. They don't know how much money you have in your bank account. I want to be very clear that in making this point about class, I'm not making the argument that race or racism don't matter in this context. 

In terms of how it plays out now, I see an awareness that has developed in the Black community in the last 10 years or so about how deeply racist the criminal justice system has become. Twenty or 30 years ago they had a consciousness, but there's levels of understanding. Many of the people I write about in the book wanted to promote the interests of the Black community. They weren't motivated by indifference or callousness. When presented with mounting evidence of how awful this system has been in Black lives, they're reconsidering and recalibrating. 

Lots of former elected officials have said to me some version of “I didn't know at the time and I appreciate that you showed us in our full complexity. I appreciate that you showed the pressures we were under. If I had known then what I know now, maybe I would have been less quick to go along with some of these harsh measures.” 

The second thing that has affected the Black political class has been the emerging movements, led by Black people in particular and led by young people. They not only educated leaders, but pressured them and made them understand that there is a political cost. If you're not moved by the moral argument, then you'll be moved by the political argument. You'll be moved by the people protesting outside the office of District Attorney Jackie Lacey in Los Angeles, for example, where Black Lives Matter LA has held, I believe, a year of consecutive protests against a Black district attorney who has had really some of the worst practices.

From what I can tell, she's been pressured by the movement to change some of her positions on important issues like prosecution of low-level drug offenders, for example, and the aggressiveness with which she prosecutes police officers for acts of violence.

What do you make of the calls to defend or even abolish the police?

What I find so compelling about abolition, initially in the prison context and extended to the police as well, is that it shifts the conversation and forces us to go through experiments in which we imagine what it would take to build that world. I think that exercise is very important, because it pushes us further than we are naturally inclined to go. Cultivating a broader imagination is an incredibly important part of this work, because as you know from my book, often it was lack of imagination that caused people to fall back on [punitive policies]. 

That's what caused D.C. Councilmember David Clarke to call the police rather than public health experts when he was overwhelmed with letters about heroin addicts in public space. He was anti-drug war, but he couldn't imagine responding to a call for help with heroin addicts with anything other than police. That's a very common move from even really good and progressive people. 

People who are for defunding, for abolition, are absolutely right about reinvesting that money into alternative structures that support communities. But the reinvestment part doesn't follow naturally from the terms. We might want to come up with a term that captures the new stuff we want to do. I think that's particularly important because one of the reasons Black communities have ended up supporting more police is that Black communities have always wanted their fair share of the resources.

Then, the evidence suggests the United States has too many police officers doing prophylactic, preventative, or stop-and-frisk style policing. The style of policing that leads to district level harassment, pulling people over for no reason. But we have too little investment in the parts of police departments that investigate unsolved crimes. I'm talking about the investigator or the detective who comes to your house after there's been a robbery, an assault, a rape, or homicide. 

As compared to European countries, in the United States we actually underinvest in those parts of our police departments. Jill Leovy’s book Ghettoside shows this in dramatic detail. She describes an LAPD that's stopping and frisking Black drivers wantonly and yet the homicide detectives are still relying on a fax machine and the fax machine is broken. They have to go with their own money to Staples to buy a printer. Meanwhile, other aspects of the department are kitted out in this ridiculous riot gear that makes them look like they're in Fallujah. 

That under investment is particularly damaging to Black communities because we're disproportionately victimised by crime. Because of racism and this allocation of resources, the police are less likely to respond in Black communities. The kids I used to work with in the charter schools in DC, we talk about no snitching, but one of the reasons they would never call the police after they'd been victimised by crime is they would say, “They're not even going to come. You're wasting time.” 

I did a Q&A with Jill Leovy too and her argument is one I've struggled to articulate in our present moment. She argues the state doesn't have a monopoly on violence in low-income Black neighbourhoods, because investigations of violence are deemphasised and crime victims or their loved ones often take retribution into their own hands.  But right now, establishing or preserving the state's monopoly on violence isn't an appealing talking point. 

Yes, this is another thing nobody's talking about. Whatever we're going to do instead of the police has to be accountable to the public. The best, most direct way to have accountability is to have the individuals be public employees. As long as we have 300 million guns in this country at least some of those state employees are going to themselves be armed. It's unreasonable to ask them to do the job without it. Not as many need to be armed as are armed now, but some of them need to be. But they can't be hiding behind union contracts or civil service protections which make it impossible to remove even the worst performing, most abusive officers. 

We can not call them police if we want to. That's semantic, but maybe symbolism matters. But those people have to be state employees. They can work with community-based nonprofits, but there are also communities that don't have as robust of a nonprofit network, and they deserve protection too. These [community] groups have to be accountable to the state and, when they don't exist, the state has to be there. 

Progressives get all the points I just made when it's applied to education. The notion that things be public and accountable to the state is understood when it comes to schools. It's exactly why so many people on the left are opposed to charter schools, because they say they don't have public accountability. They want these things to be a state function. But this point about the difficulty in removing this entirely from the hands of the state is, I think, one that liberals and progressives understand from other contexts.

Jake Blumgart is a staff writer at CityMetric.