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Biology 202
2002 Third Paper
On Serendip

Recent Studies Concerning Violent Tendencies and the Confusion that Arises

Balpreet Bhogal

"It was an urge. . . . . A strong urge, and the longer I let it go the stronger it got, to where I was taking risks to go out and kill people-risks that normally, according to my little rules of operation, I wouldn't take because they could lead to arrest." -Edmund Kemper (6)

Ted Bundy. Charles Manson. Timothy McVeigh. Bundy murdered pretty women. Manson had followers who killed on his command. McVeigh is responsible for one of the most horrendous terrorist attacks on America, the Oklahoma State bombing. While these three serial killers had different methods for their acts, the one thing they have in common is that their killers. Murderers who took a number of innocent lives.

Perhaps to not the same extent, but sadly enough the world is full of Charles Manson's and Ted Bundy's. Violence has become a common and prevalent occurrence in society today. Everyday on the news one hears stories of crimes-murder, robbery, rape, assault, extortion, kidnapping, homicide, an endless list. Law enforcement works day and night protecting neighborhoods and cities from crimes and violence, but the truth of the matter is that crime still exists and all one can do is ask himself why. Why do such treacherous violent acts exist in society? In essence, one must ask himself whether or not these violent tendencies have any biological relation whatsoever. Do violent tendencies occur as an affect of disruptions or damage to the brain? Is there a genetic correlation? Is violence brought about by some other factor, such as economic difficulties or social or cultural differences? All these questions remain unanswered. But one even significant, broader question that one must consider is whether or not these factors, biologically related and non, effect the occurrence of violent tendencies in individuals.

In 1848, a railroad worker, Phineas Gage, was working when an explosion caused an iron rod to impale his skull, damaging the front part of his brain. Although Gage miraculously survived, his behavior severely changed in that the intelligent and respectful man everyone knew suddenly because fitful, impulsive, and rude (2).

This is one of the first dated cases insinuating that violence may be related to some kind of damage or abnormality in the brain. However, with increasing technology, researchers have found many correlations between violence and aggressive tendencies to damage or abnormalities to a specific part of the brain. Gage's accident probably resulted in damage to the prefrontal cortex. The prefrontal cortex is the brain's foremost outer position, located behind the eyes. This area of the brain is especially vital because of it's importance in the orchestration of emotion, arousal, and attention. The prefrontal cortex seems to be the part of the brain that enables people to restrain themselves from acting on all of their impulses and is extremely critical for a child's ability to learn to feel remorse, conscience, and social sensitivity (5).
However, although the function of the prefrontal cortex is known, why, or how, would prefrontal deficits cause violent tendencies or a more aggressive character?

Adrian Raine, a psychopathologist from USC suggests that damage or abnormalities of the prefrontal cortex may result in a condition known as Antisocial Personality Disorder, or APD, which is characterized by irresponsibility, deceitfulness, impulsiveness, lack of emotional depth and antisocial behavior. In his study, Raine suggests three reasons why prefrontal deficits may cause such a personality (5). Firstly, the prefrontal cortex is responsible for self-restraint and deliberate foresight. If this part of the brain was damaged, then one effect that would arise would be the tendency for one to act on all his impulses without thinking ahead or thinking of the consequences. Second, the prefrontal cortex is important for learning conditioned responses. This area of the brain has been thought to be central to a child's ability to learn and to feel remorse, conscience, and social sensitivity (7). If the prefrontal cortex was to function abnormally, how is the child supposed to learn how to have a conscience? For example, one study reported that children who received damage to their prefrontal cortex before the age of seven developed abnormal social behavior, which was characterized by their inability to control their aggression and anger (2). Lastly, Raine suggests that if prefrontal deficits underlie the APD group's low levels of autonomic arousal, these people may unconsciously be trying to compensate through stimulation-seeking (5).

There have been many studies done concerning violence and its relationship to the prefrontal cortex. In July, 2000, UW-Madison psychologist Richard Davidson analyzed brain imaging data from a large, diverse group of studies on violent subjects and those predisposed to violence to find any connections between the brain and violent tendencies. Davidson and his colleagues found common neurological trends among many of their subjects in the brain's inability to properly regulate emotion. One core finding that Davidson's study found dealt with the interplay among several distinct regions of the brain, primarily the orbital frontal cortex, the anterior cingulate cortex, and the amygdala. They found that normal brain activity in the orbital and anterior regions were either entirely absent or slowed in many of their studies, while the amygdala showed normal or heightened activity. The inability of these two regions of the brain to counteract the response of the amygdala may explain how threatening situations can become explosive in some people with damage to the prefrontal cortex (4).

Although the primary focus in research deals with the prefrontal cortex, there also exist many recent studies that attempt to relate DNA and genetics to the increased tendencies for violence. Scientists have not found any specific gene for human violence, yet data from molecular geneticists suggest that multiple genes may interact to prime individuals to this behavior (1). Davidson's study also described a large group of subjects who had a genetic deficit that caused a disruption in the brain's seretonin levels. Seretonin has been hypothesized to hold inhibitory control over impulsive aggression. Disruption of the seretonin level may contribute to increased aggression within the individual (3). These biological studies-abnormalities to the prefrontal cortex and genetics-may in fact greatly influence violent and aggressive acts amongst individuals. Even though these studies cannot say for certain whether or not this is substantial evidence, researchers are on the right path for determining any biological or physiological influences towards violence.

Although such biological studies are being performed, one must also consider social influences. Adrian Raine stresses this case: "We are talking about a predisposition to antisocial behavior. Some people who have prefrontal deficits do not become antisocial, and some antisocial individuals do not have prefrontal deficits. It's important to make clear that biology is not destiny" (5). For example, socioeconomic problems may play a major role in violent tendencies. Socioeconomic problems have no biological relation whatsoever; however, it can still cause an individual to act in violent ways. Issues such as unemployment, lower educational level, alcohol use, and access to firearms all contribute to violent crimes (1). However, some of these factors can be seen as acting by way of the brain. Alcoholism can definitely have correlations to the brain. While it might not be a direct effect of prefrontal cortex damage, alcoholism might be related to genetic mutations or the brain's behavior. But other factors of society, such as socioeconomic problems or unemployment, still influence violence and criminal actions performed by individuals. Thus, not only do biological factors need to be stressed, but so do cultural and social factors.

If one believes in morals and ethics, one can also include conscience in the factors that influence violent activity. When watching serial killers and rapists on the news, a question that frequently comes up is whether or not these individuals have a conscience, the idea of knowing what is right and what is wrong. It has already been said that the prefrontal cortex has a part in teaching children the difference between wrong and right and that it develops a conscience. But if one believes that the brain is not entirely responsible for behavior and that there is something else, such as a soul, or conscience, then a lack of conscience can be an influential factor that is not related to the brain or any biological or physiological factors.

Although all the above trends and relationships implied by these studies exist, do they prove that violence influenced by some type of biological disorder or social factor? By implying this, one is assuming that every man or woman who commits a crime or acts with violent tendencies does so by some type of brain damage, genetic disorder, or social problem. If anything, by believing this, society is giving people an excuse to commit crimes and act on their violent behavior; if biological or social influences ultimately cause violence, does that redeem one's actions? If one looks at what Timothy McVeigh, Charles Manson, and Ted Bundy have done, and said that their actions can be justified by a disorder in their prefrontal cortex or some other physiological factor, what does that leave us as a society with? Are the crimes committed by these serial killers justified? Should they be set free because they couldn't "control" their actions?

Perhaps, in some to many cases, an individual's tendency to act in violence is influenced by biological abnormalities of the brain or other physiological factors. But how can one know for certain whether or not this is the case? Currently, there is no way to determine how extensive the these factors influence violence and aggression. One could believe the criminal when he says he wouldn't have committed a crime if his prefrontal cortex was damaged. But then that brings up the question on whether or not his word is reliable. On the one hand, criminals could use these factors as an excuse to get out of jail and commit more crimes; or, on the other hand, the individual could be telling the truth, and, with treatment and medications, he could live the rest of his life without even littering a gum wrapper. But the truth of the matter is there is no way of knowing yet if these factors discussed are the reasons for violence. Unless technology advances in the future allowing scientists to know for sure if violence is influenced by factors, the crimes committed by the Ted Bundy's and Timothy McVeigh's in the world cannot be justified.

There are many issues when discussing violence. While it is a serious issue, it is also a rather sensitive one. One would think that after seeing acts of violence constantly everywhere-in movies, video games, the nightly news, professional sports and other forms of entertainment-society would be used to it by now. But how can one ever get used to violence? All these issues remain unanswered. While there is a substantial amount of recent research that involves different biological and physiological factors for violent tendencies, it is still too soon to make any determinations. Aside from scientific research, there arises the moral issues as well, whether or not these criminals should be free in society instead of locked away in prison. Criminals like Ted Bundy, or Timothy McVeigh. Can these influential factors justify the murders, rapes, robberies, and other crimes that occur every day in society? A correlation between brain damage and violence might have been found, but how to act on this newfound discovery still remains ambiguous. And until the next step is taken in research and discussing what should be done, society cannot move forward in eliminating the everyday violence.


1) Violence and Brain: An Urgent Need for Research

2) Brain Briefings: Violent Brains

3) Dysfunction in the Neural Circuitry of emotion Regulation-A Possible Prelude to Violence

4) Violent Behavior Linked To Specific Brain Dysfunction

5) Size of Brain Linked to Violence

6) The Criminal Mind

7) Brain Size Linked to Violence

8) Mark, Vernon H. Violence and the Brain. New York: Harper & Row Publishers, 1970.

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