The Neurobiology of Aggressive and Antisocial Behavior

Antisocial and aggressive behavior is linked to gray matter brain abnormalities.

Posted Dec 13, 2015

Johan Swanepoel/Shutterstock
Antisocial and aggresive behavior is associated with less gray matter brain volume in key regions. 
Source: Johan Swanepoel/Shutterstock

A new study by researchers in the UK has identified that young people with behavioral problems—such as antisocial and aggressive behavior—show reduced gray matter volume in a number of brain areas. 

Specifically, the University of Birmingham researchers found that, compared to typically developing youths, those with behavioral problems show gray matter reductions within the amygdala, insula, and prefrontal cortex. These brain areas are important for executive function, interpretting facial expressions, empathy, decision-making, and emotion regulation

The December 2015 study, “Cortical and Subcortical Gray Matter Volume in Youths With Conduct Problems,” was published in JAMA Psychiatry. In a press release, Dr. Stephane De Brito, lead author of the paper said, 

"We know that severe behavioral problems in youths are not only predictive of antisocial and aggressive behavior in adulthood, but also substance misuse, mental health problems and poor physical health. For that reason, behavioral problems are an essential target for prevention efforts and our study advances understanding of the brain regions associated with aggressive and antisocial behavior in youths."

Although this is one of the largest studies of its kind, many unanswered questions remain in terms of identifying the correlation and causation between brain structures and maladaptive behaviors. For example, it's difficult to know whether these structural brain differences are primarily caused by genetics, or environmental factors such as smoking/substance abuse during pregnancy, socioeconomic strains, maltreatment in early childhood, etc. 

De Brito concluded, "Some of those important questions will be addressed in the context of a large multisite study we are involved in. This research will be carried out on children and adolescents from seven European countries to examine the environmental and neurobiological factors implicated in the development of behavioral problems in male and female youths."

The Ever-Changing Fabric of Our Minds

Courtesy of Viking
Source: Courtesy of Viking

I learned just about everything I know about neuroscience from my father, Richard Bergland, M.D., who spent much of his career as chief of neurosurgery, and as a neuroscientist, at Harvard Medical School’s Beth Israel Deaconess Hospital. My dad was also the author of The Fabric of Mind (Viking). He had a wonderful ability to explain complex neuroscience without dumbing it down.

Whenever my father explained brain science to me, he broke lessons into three categories: Electrical (Brain Waves), Chemical (Neurotransmitters), Architectural (Brain Structure.) Each of these three arenas are ever-changing within every moment, day, and year of our lives. The fabric of our minds is like a tapestry that is always adapting, at a neurobiological level, to maintain homeostasis within our environment.

For example, when you’re awake, most people exhibit brain wave electrical patterns on an EEG that can be classified into two types of waves, beta and alpha. However, when you sleep or are deep in meditation, your brain waves can also include theta and delta waves.

In terms of neurochemicals and hormones, “fight-or-flight” stressors can trigger the release of adrenaline and cortisol, while “tend-and-befriend” stimuli would be associated with dopamine and oxytocin. Lastly regarding architecture, brain structure and functional connectivity between brain regions are impacted by neuroplasticity, neural pruning, and neurogenesis (growth of new neurons). Together, these influences can alter the integrity of white matter connectivity between brain regions, as well as the gray matter volume of specific brain regions.

I spoke to my father daily while I was writing the manuscript for The Athlete's Way: Sweat and the Biology of Bliss. Together we created a prescriptive based on this triad of electrical, chemical, and architectural brain changes that people from all walks of life could implement to create peak performance and a mindset of magnanimous 'sportsmanlike conduct,' both on and off the court. 

As a young aspiring athlete, I played tennis almost every day. My father was often my coach, and pounded it into my head that through repetition and practice, practice, practice, I could reshape my brain and rewire neural connections. Through sports, I learned that mindset and muscle memory is never fixed and that neuroplasticity was in the locus of my control, and that of my coaches. 

Hebbian Theory: "Neurons that fire together, wire together." 

In the mid-20th century, Donald O. Hebb identified the principles of neuroplasticity. My father incorporated these concepts into his athletic coaching, which was very helpful for me as an athlete in terms of optimizing my athletic mindset and muscle memory. 

The bad news about neuroplasticity is that it can also be used to “brainwash” people. In the 1950s, Hebb and his colleagues participated in various types of government-funded research to understand the implications of sensory deprivation and other interrogation techniques used to tamper with the electrical, chemical, and architecture of the brain.

Neuroplasticity makes “mind control” and “radicalization” a possibility at any stage of life. However, the youthful brain is much more vulnerable to plasticity than the adult brain. Therefore, it’s important for parents, teachers, and policymakers to remember that we have a huge responsibility to create environments that don’t nurture aggressive and antisocial behavior. As a society, we must have zero tolerance for hate speech, bigotry, and discrimination.

A September 2013 study from the Department of Psychology at the University of Chicago published in journal Frontiers in Human Neuroscience identified the neurobiological roots of psychopathic behavior. When highly psychopathic participants imagined pain to themselves, they showed a typical neural response within the brain regions involved in empathy for pain, including the anterior insula, the anterior midcingulate cortex, somatosensory cortex, and the right amygdala.

However, the increase in brain activity in these regions was unusually pronounced, suggesting that psychopathic people are sensitive to the thought of pain, but are unable to put themselves in someone else’s shoes and feel another person's pain. That said, another study from 2013 found that empathy and compassion can be learned. It's always possible to change one's brain structure and functional connectivity in positive ways. I wrote a Psychology Today blog post based on this research, "The Neuroscience of Empathy." 

In 2014, Neuroscientists in Italy reported that “social pain” activates the same brain regions in the insula as physical pain. The researchers also found that witnessing the social pain of another person activated a similar physical pain response of empathy in most test subjects.

Conclusion: Empathy and Compassion Can be Learned

Regardless of gray matter volumes in childhood, the structure of our brain and the architecture of our mind is never set in stone. Therefore, we must stay vigilant through daily practices to nurture real-world environments that promote healthy internal neurobiological environments, not heartless or hateful ones. 

Lately, with so much fear and terrorism dominating the airwaves and invading our living rooms, it seems that fear is causing a knee-jerk reaction to become aggressive, antisocial, and xenophobic. We must come together in the name of loving-kindness and equanimity to stop the power of ignorance and hatred from creating neurobiological changes rooted in aggression and antisocial behavior from invading our minds.

In closing, I’d like to share with you “A Statement on Anti-Muslim Rhetoric” from Union Theological Seminary in New York City that addresses the dangers of Islamophobia. The December 9, 2015 statement was originally posted on Union's Facebook page:

"Fear-mongering based on anti-Muslim hate is at its most visible, with recent calls by political candidates for a ban on Muslim immigration, for closings of mosques, and for the registration of Muslim Americans.

This is a dangerous moment in America and we pray that this isn’t the turn towards fascism it appears to be. Reports of hate crimes against Muslims and those who “appear” Muslim are also on the rise. We are morally and religiously appalled by this turn of events, and we are frightened not only by the language of leaders, but by the hatred it seems to inspire in increasingly large audiences. But, American Islamophobia did not start with any recent political speech. It goes back decades and generations, and is part of a larger system that thrives on the dehumanization, scapegoating, and marginalization of diverse communities.

As a religious and educational institution, we unequivocally condemn any action, statement, sentiment, or policy that denigrates the full dignity and humanity of our Muslim neighbors. At Union, we work to build leaders for communities that welcome all people, embracing all races, genders, religions, sexual orientations, ages, and abilities. Our field of Interreligious Engagement promotes groundbreaking academic and public work on this critical topic, and we are grateful for the contributions of our Professor of Islam and Ministry, Jerusha Lamptey. In this moment, may we stand together in solidarity to transform divisions rooted in bigotry, hatred, and fear into a community of radical inclusion and revolutionary love.

We hope in the deepest places of our hearts that you will join the community of Union to work to share this message of revolutionary love."

Daily habits and behaviors change the electrical, chemical, and architecture of your brain. As parents, caregivers, educators we must strive to create nurturing, loving environments for our children that optimize the gray volume and white matter integrity of their brains through neural pruning, neuroplasticity, and neurogenesis.

Social connectivity, physical touch, regular exercise, getting enough sleep, mindfulness, and loving-kindness meditation (LKM) have all been proven to benefit brain structure and function. LKM is a simple four-step process that only takes a few moments each day. To practice LKM, all you need to do is systematically send compassion, empathy, and loving-kindness to four categories of people:

  1. Friends, family, and loved ones. 
  2. Strangers around the world and locally who are suffering.
  3. Someone you know who has hurt, betrayed, or violated you.
  4. Forgive yourself for any negativity or harm you’ve caused yourself or others.

Doing LKM for just a few minutes every day can help rewire and restructure the brain, and help keep aggressive and antisocial behavior at bay for people of all ages.

To read more on this topic, check out my Psychology Today blog posts: 

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