Graph showing increase in people incarcerated from 1925 -2015

ABSTRACT - Neurocriminology is a subdiscipline of neuroscience and criminology which provides evidence that while violent behavior has a social and environmental element, the other side of the coin is biology. This re-visioning of violent criminals could potentially help direct how we approach crime prevention and rehabilitation. Criminal behavior can be caused by life experience and by genetic inheritance. This paper shines a light on evidence that physical trauma to the brain and genetically inherited abnormalities of the brain can be the cause of violent behavior. Instead of sentencing violent people to death or life in prison, society can treat them medically by using the science of neurocriminology as a guide to improved rehabilitation and prevention of the development of a criminal mind.


We’ve all read an article or heard from someone about notorious individuals who commit horrific crimes, and we often ask ourselves what drives people to kill, rape, steal, and simply be too violent? Throughout the years, criminals have been treated like bad apples that need to be stored away for good, and usually if you don’t fix the origin that’s causing these bad apples, then we will never find a solution. On the outside, violent offenders come in all shapes, sizes, colors and ages. But on the inside, research finds that they may share some traits. Just as a biological basis exists for schizophrenia, anxiety disorders and depression, it may be logical to say a biological basis also exists to recidivistic violent offending. The re-visioning of violent criminals by the world could potentially help direct how we approach crime prevention and rehabilitation. Moreover, the genetic inheritance and life experiences of a human being play a huge role in shaping our personality and mind.

Humans are interesting creatures. The only significant thing that separates us from other species is our brain’s advancement. A human brain can be described as a genius symphony put together to harmonize a beautiful masterpiece. Each lobe in our brain plays a crucial role in shaping our life. Many associate emotions with the heart, but in fact the ability to express all sorts of emotion is thanks to the limbic system, and the ability to differentiate what is right from what is wrong is credited to our frontal lobe. They are both in different parts of our brain that give us the unique ability of being “human,” which in my opinion is what separates us from other creatures on this planet. So what if a person has a broken frontal lobe and limbic system? In more general terms, what if a person doesn’t have the ability to feel and express his/her emotion like any other “normal” person? Is this specific individual no longer referred to as “human”? Is this individual more likely to have a criminal mind?

Twenty years ago, when brain imaging made it possible for researchers to study the minds of violent criminals and compare them to the brain imaging of “normal” people, a whole new field of research — neurocriminology — opened up. Neurocriminology was founded by Dr. Adrian Raine, a British professor at the University of Pennsylvania. He was the first person to conduct a brain imaging study on murderers and has since continued to study the brains of violent criminals and psychopaths. His research convinced him that while violent behavior has a social and environmental element, there is another side of the coin, and that side is biology. This re-visioning of violent criminals could potentially help direct how we approach crime prevention and rehabilitation.

In order to really understand the purpose behind neurocriminology, one must understand the parts of the brain, their functions, and how an injury/deformity to any parts of the brain can shape an individual’s whole life. The cerebral cortex (aka the gray matter) consists of four lobes in addition to other vital parts of a person’s brain that help process his/her emotion and behavior. The frontal lobe lies in the area of the brain directly behind the forehead. The frontal lobe is the largest “section” of the brain and is responsible for many of the unique abilities that make us human. This area of the brain is responsible for reasoning, memory, concentrating, organizing, information processing, and judgment. While most parts of your brain can be affected by an accident, the frontal lobe is the most vulnerable area. It is also one of the most exposed and most used parts of the brain, making injuries there frequent and devastating. A person with frontal lobe brain damage may develop a completely different personality. Think of the frontal lobe as the part of the brain that defines and houses your personality. Since the frontal lobe is directly behind the forehead, an impact from any side can affect it. When struck, the brain moves within the skull. A strike to any part of the head can cause rebounding and secondary impacts, which are likely to affect the frontal lobe. When the brain hits the inside of the skull, bruising, lacerations, swelling, and other damage can impact the front lobe. Within the frontal lobe, the most susceptible area to injury lies at the very front of the brain behind the skull. This small area of the brain largely controls the personality-creating functionality mentioned earlier. Depending on where the prefrontal cortex is damaged, a variety of symptoms can arise.

One of the most famous cases of brain injury studied by neuroscientists and psychologists over the years is that of “Phineas Gage, an individual who was impaled with a railroad spike in 1848. The impact of the injury affected one side of his brain. He could speak, function, and remember events well, but those who knew him before did not recognize his personality after the accident. He lost his ability to focus and grew impatient and irritable; personality traits that starkly contrasted to the Phineas Gage friends and relatives knew before the accident” (Costandi, 2010). Depending on a victim’s age and the area of injury, the symptoms of a brain injury can look very different from person to person. In addition to the immediate symptoms of an injury, including swelling, bruising, loss of consciousness, seizures, or nausea and vomiting, frontal lobe injuries affect the way a person fundamentally behaves, such as erratic behavior or loss of judgment, uncharacteristic impulsivity, increased irritability, aggression, and loss of focus.

A person may experience some of these symptoms if not all after a traumatic injury. Many criminals have shown low brain activity in the prefrontal cortex, and through Dr. Raine’s study using brain imaging techniques we are able to understand the brain activity of a criminal in comparison to a “normal brain” more thoroughly. Dr. Raine “conducted PET [positron emission tomography] scans of 41 convicted killers and paired them with a ‘normal’ control group of 41 people of similar age and profile. However limited the control, the color images, which showed metabolic activity in different parts of the brain, appeared striking in comparison. In particular, the murderers’ brains showed what appeared to be a significant reduction in the development of the prefrontal cortex, ‘the executive function’ of the brain, compared with the control group” (Adams, 2013). This study serves as scientific proof that people with violent tendencies do have irregular brain activity when compared to the brain of a nonviolent person.

In some cases, when an individual is diagnosed with a mental illness, he or she is no longer fit to function in society due to their uncontrolled behavior and brain function. They are now medical patients that have been diagnosed and getting treated. When a person is showing clear signs of an abnormal brain activity, specifically in the frontal lobe, should that person be considered a medical patient?

The most dangerous people who commit a crime aren’t those with a damaged frontal lobe, but in fact a damaged amygdala, which is a part of the limbic system located in our brain. The amygdala is involved with fear, aggression, guilt, social interactions, and remorse. An injury to the amygdala will cause an individual to lose their human emotion in a way. Imagine having a violent person with a functioning frontal lobe but a damaged amygdala. This person will be able to plan his/her crimes like a “normal person” but won’t be able to feel any remorse or fear in committing these crimes.

An abnormal amygdala doesn’t have to be a result of an injury or a trauma. The size of an amygdala can also be associated with aggressive tendencies and loss of emotion. “A neuroimaging study led by Dustin Pardini, PhD, of the University of Pittsburgh. His team found that 26-year-old men with lower amygdala volumes were more than three times more likely to be aggressive, violent and to show psychopathic traits three years later than men of the same age with more normal-sized amygdala” (Miller, 2014). A genotype conferring low levels of the enzyme monoamine oxidase A (MAOA), when combined with early child abuse, predisposed the individual to later antisocial behavior. Low MAOA has been linked to reduced volume in the amygdala—the emotional center of the brain—while physical child abuse can damage the frontal part of the brain, resulting in a double hit. This fact brings nature and nurture together as a one reason behind a disrupted amygdala and frontal lobe.

A person with a smaller than usual amygdala will also demonstrate little to no signs of fear and anxiety. Dr. Adrian Raine, D.Phil., at the University of Pennsylvania, with Yu Gao, Ph.D., at CUNY-Brooklyn, led a study that examined fear conditioning. A group of 1,795 three-year-old children had electrodes placed on their fingers to examine their fear and anxiety level when introduced to an unpleasant stimulus, and a pleasant stimulus. The difference in sweat response to stimuli by itself produced a measure of each toddler’s fear conditioning. Forward twenty years later, the study team identified participants who had gone on to commit crimes and compared them with non-criminal counterparts. They found that those children who went on to commit crimes had “simply failed” to demonstrate fear conditioning; they were fearless when most of us would be fearful. This finding suggests that deficits in the amygdala, which are indirectly identifiable as early as age 3, predispose to crime at age 23 (“Association of Poor Childhood Fear Conditioning and Adult Crime,” 2010).

If we know that certain brain characteristics may predispose some people to violence, what can we do about it? Intervene — and the earlier, the better, says Raine, author of The Anatomy of Violence. In one intervention, for example, he and his colleagues found that 3-year-olds who had been assigned to an enrichment program focused on nutrition, exercise and cognitive skills had better brain functioning at age 11 and a 34 percent reduction in criminal activity at age 23 when compared with a control group that did not receive the intervention (Miller, 2014). Intervening even earlier, David Olds, Ph.D., of the University of Colorado, has found that pregnant low-income mothers who were visited regularly by home nurses who talked to them about health, education and parenting were less likely to have children who were arrested by age 15 (Olds, 2006).

Even simple interventions may make a difference. In one preliminary study, prisoners assigned to a 10-week yoga class improved their impulse control (Miller, 2014). In an earlier randomized-controlled trial of British prisoners, those who received vitamin, mineral and essential fatty acid supplements committed an average of 26.3 percent fewer offenses than those who had received the placebo. They also showed a reduction in offenses of more than 35 percent, while the placebo-taking prisoners’ records remained stable (GESCH, 2002).

Many people would argue that there are people who are criminals that don’t necessarily have an abnormal brain chemistry, and that they, in fact, were made criminals through life experience. So can life experiences actually make a criminal? Donta Page is a convicted murderer, who in 1999 robbed a young woman in Denver, raped her, slit her throat and killed her by plunging a kitchen knife into her chest. Page as a child suffered from poor nutrition, severe parental neglect, sustained physical and sexual abuse, early head injuries, learning disabilities, poor cognitive functioning and lead exposure. He also had a family history of mental illness. By the age of 18, Page had been referred for psychological treatment 19 times, but he had never once received treatment. A PET scan was taken of Page’s brain, which suggested that murderer Donta Page had relatively low glucose metabolism-the basic fuel that powers most cell functions in the ventral prefrontal cortex — the area of the brain that helps regulate emotions and control impulses (Raine, 2013). This helps explain his strong emotions, impulsivity, and violence. Here we have a criminal who had a troubled upbringing, checked every box of a violent and abnormal behavior, and still was allowed to be part of society. He was a ticking bomb waiting to explode.

For a “normal” individual, murder can not be justified. Self defense, however, is grasped differently. According to an ABC News story, a young woman shot and killed an intruder to protect her 3-month-old baby. When the intruder kicked in the door and came after her with the knife, the teen mom shot and killed the invader. Police called the shooting justified. “You’re allowed to shoot an unauthorized person that is in your home. The law provides you the remedy, and sanctions the use of deadly force,” Det. Dan Huff of the Blanchard police said. This mother was not convicted of committing a crime because her act of violence was that of self defense, i.e., “she did what had to be done” to protect her baby (Dolak & Owens, 2012). Another moral justification for killing is that during war. The act of killing another human being is also that of self-defense. Soldiers are willing to perform any task in order to defend their land and serve their country. Both these cases demonstrate that anyone is willing to kill if killing is justified and is done out of self-defense.

We talked about how a violent person’s brain doesn’t usually function the same as a “normal” brain. If killing out of self defense is a reason to justify this act through society’s perspective, committing a crime in a criminal’s viewpoint can also be justified by his/her own damaged perspective. What is wrong in our eyes can be completely right in an offender’s perception. This statement does not justify the acts of a criminal, but instead it helps us better understand what can be going on inside a criminal’s mind.

Whether it was genetic inheritance, life experiences, or both that helped create a criminal, it is beneficial that we get a better understanding on what goes on inside a violent brain. It is a nice idea to believe that humans are designed to never be violent, but the number of criminals in the U.S. alone proves otherwise. Regardless if a person is born with a bad brain, or is made bad, we as a society should treat these individuals as medical patients instead of treating them as criminals who deserve to be sentenced to death or be locked up for life.

The number of crimes has been on the rise. According to a USA Today article, “U.S. cities saw 6,407 homicides in 2016, an 11% increase from the year before...about a quarter of women, men, and juveniles who are released, for example, return to the system within six months; and 70% do so within five years” (Kevin, 2017). This data shows that recidivism is an ongoing problem in the U.S. today. Our prison systems are failing us and our inmates. Whatever structure being followed in order to prevent and rehabilitate criminals is not producing efficient results as it should. Neurocriminology aims to research different and improved methods to help decrease crime rate by implementing appropriate rehabilitation methods. The study of crime from its neurological and biological side has helped us take a more empathetic, understanding and merciful approach toward both the victims of violence and the prisoners themselves. It is a step forward in a process that should express the highest values of our civilization.


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