Research Related to A Correlation Between The Brain And The Act Of Violence

There have been many different ideas about the function of the brain throughout history. Some prominent figures had their own ideas about the brain: Aristotle thought it was a radiator to cool blood, Descartes thought it was an antenna for the spirit to communicate with the body, and now we know that it is behind everything we do. It controls our hearing, touching, seeing, moving, speaking, tasting, feeling, thinking, and anything else one could think of. The brain is what makes people act and believe in everything they do.

It is stated that at least 40% of one’s personality is due to genetics. It seems that almost everything people do is based upon genes given to them.

One aspect within one’s personality is anger, which likely can lead to one committing a violent act. The question of whether violence is genetic has plagued many individuals in society. The complete answer to that question may be unknown, for now, but there are multiple articles explaining how there could be a correlation between the brain and the act of violence.

The main arguments entail some specific genes, low activation zones, and how the heart rate can affect the body.

There have been multiple speculations that certain genes makes people commit violent acts; while that is not true, it does raise the likelihood that one could commit the act compared to an average person. It turns out that the most violent offenders were considerably more likely to have combinations of certain variants of the MAOA and CDH13 genes.

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The MAOA gene variant known as the “warrior” gene is a variant for the promoter region of the gene, coding for a less active MAOA enzyme. Since this enzyme lingers inside cells and breaks down neurotransmitters, having less active MAOA means more neurotransmitters (dopamine, norepinephrine, epinephrine, and dopamine) are available. This can lead to a protection against depression (although the results are mixed), but it is also possible that it could lead to more impulsive and violent behavior. The discussion to whether the MAOA gene could lead to more impulsive behavior is mixed, over the years, the “warrior gene” has presented itself in the discussion about violence, as to whether it, in combination with maltreatment as a child, leads to sociopathy in adults. The CDH13 gene codes for a neuronal membrane adhesion protein. It has a questionable link to alcoholism (Deans, 2014).

Researchers Tiihonen, Rautiainen, Ollila, Repo-Tiihonen, Virkkunen, Palotie, Pietiläinen, Kristiansson, Joukamaa, Lauerma, Saarela, Tyni, Vartiainen, Paananen, Goldman, and Paunio found that when looking at the most violent offenders (defined as having committed more than 10 seriously violent crimes), those prisoners who had a combination of the less active MAOA and the risk allele for CDH13 were more likely to be in that small group of super violent repeat offenders. (Tiihonen et al., 2014). Although the links between the above genes and the general prison population were not significant, when compared to the sample from Tiihonen et al., the study the calculated odds ratio of having the MAOA and the CDH13 in super violent repeating offenders was 13.45.

Normally, an odds ratio of more than 2 makes is large enough to create interest and intrigue. An odds ratio means that the odds that an outcome will occur given a particular exposure, compared to the odds of the outcome occurring in the absence of that exposure, so an odds ratio of 13.45 is very high that the MAOA and CDH13 gene is prevalent in extremely violent repeating offenders compared to the general prison population. It is possible that a combination of the less active MAOA enzyme and a genetic issue with neuronal membranes puts someone at higher risk for becoming violent (Deans, 2014). It must be said that most of the population has the so-called “warrior” gene (depending on race, around 40-50%). Most of the extremely violent offenders did not have the highly risky combo of genes found in the study. Human behavior is explained by a combination of environment and a complex interaction of multiple genes.

Whenever anyone lies, no matter the reason for the lie, there is increased activation in the prefrontal cortex as well as areas in the parietal cortex. This finding has been supported in Hong Kong, England, and the United States; these results have spanned three different continents and cultures. One may argue how this can relate to violence; deceit is an antisocial act that is a complex executive function that requires a lot of frontal lobe processing. When faced with a moral dilemma, an average person’s brain shows increased activation in a circuit that compromises the medial prefrontal cortex, the angular gyrus, the posterior cingulate, and the amygdala.

In an average person’s brain, the function of the medial prefrontal cortex is to learn associations between context, locations, events, and corresponding adaptive responses, particularly emotional responses (Euston, Gruber, & McNaughton, 2012). The angular gyrus (which is in the parietal lobe) it is the part of the brain associated with complex language functions (i.e. reading, writing and interpretation of what is written). The posterior cingulate (part of the limbic system) which receives inputs from the thalamus and the neocortex. It is an integral part of the limbic system, which is involved with emotion formation and processing, learning, and memory. The amygdala is responsible for the perception of emotions such as anger, fear, and sadness, as well as the controlling of aggression. These brain areas contribute to complex thinking, and the ability to step outside of oneself and evaluate the bigger social picture. A violent individual may have abnormalities in these parts of the brain which aided in them committing their violent acts. To look at these abnormalities the would do an MRI scan to look at the neuronal and axonal matter, and a PET scan to look at which parts of the brain is not activating properly — either not enough or too much activity.

The ventral prefrontal region is critical for making “appropriate” moral decisions, or at least passive decisions that result in no harm to others. These parts of the brain – prefrontal cortex and limbic system – seem to be misfiring in violent offenders. Some studies of antisocial individuals show poorer functioning or abnormalities in the angular gyrus, abnormalities in the posterior cingulate, the amygdala, and the hippocampus (Raine, 2014). Other studies show that there is abnormal functioning in the superior temporal gyrus in violent offenders. Overall, when comparing the offender’s brain to an average person’s brain, one can see that some parts critical for thinking morally do not seem to be functioning very well.

There has been evidence to show how low cardiovascular arousal and violence has a relationship. This relationship has started to become significant and possibly heart rate could be considered a biomarker for the diagnosis of conduct disorder, because it is is diagnostically specific, and it is extremely cheap and quick to assess. Not everyone with a low heart rate will become a violent offender. There are two main arguments to explain why a low heart rate relates to violent behavior.

The first argument is a fearlessness theory; a low heart rate is thought to reflect a lack of fear. The support is from studies on infancy and childhood, which showed that a low heart rate provides the underpinning for a fearless, uninhibited temperament and the more uninhibited the preschooler is, the more likely it is that they will show a higher rate of aggression later in life. The people with low heart rates tends to have a better ability to deal with stress, indicating that they are more insensitive to social stressors. Since they have a low resting heart rate, they feel less fear or anxiety from certain actions that others may be scared to do.

The second argument entails stimulation-seeking theory, “which argues that low arousal represents an unpleasant psychological state and that those who display antisocial behavior seek stimulation to increase their arousal levels to optimal level” (Raine, 2013). Everyone has an optimal level in which he or she feels comfortable. Resting heart rate is at its lowest during adolescence; that craving for arousal may be part of the reason violence peaks in the late teenage years. This theory was tested in the small island Mauritius, where 1,795 three-year-olds were brought to a research lab in which the researchers would watch whether the children left the comforts of their mothers to go play with all the toys around them. The ones that had no trouble leaving their mother were rated as stimulation-seekers or explorers. Eight years later, the children were rated by their parents using a checklist of child behavior problems; the high stimulation seekers at age three were found to be more aggressive at age eleven. Although there may be a relationship between low resting heart rates and aggression, it does not mean people who have these attributes will commit violent crimes; the same biological predispositions can result in very different outcomes (Raine, 2013). At the same time, these biological warning can give a sense of potential problems for the future.

There are people who disagree with Raine’s belief that violence is genetic; the main argument would entail in that people learn to be violent through their environment and what occurs inside it, like video games. A study by Willoughby, Adachi, and Good (2012) examined sustained violent video game play and adolescent aggressive behavior across the high school years. They found that as participants who played violent video games throughout high school also reported steeper increases in aggressive behavior over time than participants with a lower sustained playing of violent video games scores. Overall, the results offer support for the suggestion that violent video game play may be linked to greater aggression over time (Willoughby et al., 2012). This may be true, but it does not change the fact that there is a biological predisposition out there; in fact, the adolescents with the low resting heart rates may have been the students participating in this study and the violent video games is a way to raise their arousal level to the optimal level.

Another argument could simply be since these biological predispositions do not cause everyone to be violent, can one even say that is why people are violent? This argument can be considered wrong because they did not understand the wording of the information. It is not known that these biological aspects cause violence, but it is known that there is a relationship between the two. A person with these predispositions may be more aggressive compared to an individual without these aspects. This does not mean that as a society we should lock up everyone who has these attributes. It is just a warning to what could occur in the future, not that it will.

The last argument is one that aligns with the idea that genetics can affect violent tendencies, but it is not only that, environment plays a part too. It is stated that an abused child is at risk for becoming violent, delinquent, or criminal later in life; that experience has given the opportunity to miss a life without violence and it can become all they know. The environmental and biological studies of criminality and delinquency shows that there is clear that offensive behavior is a multifactorial disorder, with contributors possibly including such variables as low IQ, attention deficit disorder with hyperactivity, and early aggressiveness. Protective factors possibly include high IQ and shyness. Each of these factors has been shown to be moderately to highly heritable (DiLalla & Gottesman, 1991). This study argues that while violent tendencies can be heritable that is not the entire picture. This argument does not actually void the original one; violence can still be tracked by biological predispositions, but this is saying violence is the product of both environmental stimulation and genetics.

It is true that there are multiple genetic or hereditary aspects that can lead to someone committing more violent acts than others, but that does not mean someone with “bad wiring” will commit violent acts. Yes, violence can be trackable through one’s body on the predictability that violence could occur. It cannot tell you if a person will be violent or will act upon violent tendencies. Biology is not destiny; these genetic aspects are not dictatorial, because one’s character is the product of many complex factors. Those undesirable genes one has can be neutralized by non-genetic and intervening components. Yes, there are aspects to which one can believe that violence is genetic or predisposition to commit violent acts, like genes, activation spots, and how one’s heart rate, but that is not the whole story. One’s anatomy does not dictate their story or life.

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Research Related to A Correlation Between The Brain And The Act Of Violence. (2022, Jul 16). Retrieved from

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