This paper reflects the research and thoughts of a student at the time the paper was written for a course at Bryn Mawr College. Like other materials on Serendip, it is not intended to be "authoritative" but rather to help others further develop their own explorations. Web links were active as of the time the paper was posted but are not updated.
2004 First Web Paper
The recently-released film "Monster" is based upon the story of female serial killer Aileen "Lee" Wuornos. This movie raises several interesting questions regarding the nature of homicide, specifically that which is carried out in cold blood, and its causes. What makes people commit murder? Is it a question of underlying aggression? If so, how does this differ among individuals? In combining aspects of the movie with those of Wuornos' real life, the purpose of this paper will be to attempt to identify several factors in the lives of both the fictionalized and actual murderer that may provide some explanation or at the very least, a discussion of certain neurobiological and psychological factors and their roles in homicide and aggression among the general population and more specifically, among women.
"Monster" in some ways portrays the life of a victim. Through flashbacks to her childhood and the mention of it later in the film, the audience is made of aware of the sexual abuse that the young Aileen endured. Research has shown that there are several aspects of an abusive childhood that remain with the child for the rest her life. The impact of child abuse alone, whether physical, sexual or emotional, can over time result in disruptions of mood, including depression and anxiety, and in antisocial traits such as aggression, criminal behavior and impulse control (1). In his article on the neurobiology of child abuse, Martin Teicher discusses the effects that child abuse has been hypothesized to have on certain areas of the brain, particularly the limbic system. This system is described to be the area of the brain that is essential in the development of emotional responses and the recollection of memories. Within the limbic system are the hippocampus and the amygdala, which are thought to be key components of "the formation and retrieval of both verbal and emotional memories" and of "creating the emotional content of memory – for example, feelings relating to fear conditioning and aggressive responses," respectively (1). Research has led to the discovery of a correlation between an early history of abuse and decreases in the size of the adult hippocampus and amygdala. The smaller these brain structures, the greater the likelihood of over-stimulation, to the effect that the individual would be more traumatized by the memories and be more closely attached to the emotions recalled. In addition, given a person's history of maltreatment, the responses brought forth in any perceived threat, regardless of the severity, could be representative of those continually initiated in the past or of the desire to react differently. In the latter case, it can be said that an overly aggressive response blatantly disproportionate to an event, however slight, would occur to counter a past threat in which the individual was unable to be aggressive.
Although the true account of her childhood is sketchy, due to several different accounts given by Lee, it was confirmed by professionals who testified on her behalf that she had borderline personality disorder (2),(3). Individuals suffering from this disorder exhibit difficulties with the regulation of their emotions in that they can be vastly antithetical from one moment to the next. Acute yet ephemeral anger and aggression is sometimes a by-product, and impulsivity can prove to be a problem as well. Research has shown that a history of abuse, neglect or separation is common among a large percentage of individuals with borderline personality disorder, particularly in those who have suffered sexual abuse (4). Thus, it is most likely the case that Wuornos' real life was marred by the occurrence of such maltreatment.
Under this assumption, there are neurobiological reasons that may explain why and how Lee developed borderline personality disorder in the first place. It has been found that the middle part of the corpus callosum – which is essentially the bridge that allows information to travel between hemispheres of the brain – in females who endured sexual abuse tended to be much smaller than in individuals who reported no abuse. This then reduces the amount of communication or integration that can take place between hemispheres at any given time. Lack of integration forces one hemisphere to dominate the emotions of the individual; presumably, the dominating source of emotion can change almost instantaneously and randomly, resulting in rapid fluctuations in perception that are notably characteristic of the borderline personality (1).
In conjunction with this reduced size of the corpus callosum may be a significantly decreased flow of blood in the cerebellar vermis – the middle part of the cerebellum – which plays a role in controlling the presence of norepinephrine and dopamine in the brain. These are neurotransmitters that govern the shift to "a more right hemisphere-biased (emotional) state," and "a more left hemisphere-biased (verbal) state," respectively (1). Research has shown that people with an abusive past exhibit a diminished amount of blood flow in the vermis, which disrupts its ability to regulate the production and discharge of the above neurotransmitters, thus increasing the risk for sporadic hemispheric shifts, leading to the borderline behaviors described earlier. As was previously stated, a history of separation is prevalent among those with borderline personality disorder. Wuornos was abandoned by her mother when she was a toddler, only to be raised by an alcoholic grandfather and her grandmother (3). Perhaps this too led to the neurological development that fosters such a disorder.
Although borderline personality disorder may lead to bursts of extreme anger, this does not completely explain how or why Wuornos came to commit the heinous crimes that she did. She began prostituting in her early teens, and the film portrays a brutal rape scene, taking place in her early thirties, in which she is attacked by one of her johns. This marks the beginning of the end as she, in self-defense, kills her rapist. It is plausible enough to believe that self-defense led her to kill. However, the same does not hold true for the five or six other murders that she committed. Is it possible to believe that one day she just snapped? Viewing the situation from the film's point of view, it is. Women who have been sexually assaulted most likely develop post-traumatic stress disorder (5), symptoms of which may include flashbacks, emotional numbness and sporadic and spontaneous occurrences of anger (5),(6). "Monster" shows Lee having a flashback to her rape during her second murder. Individuals with PTSD tend to have relatively low levels of cortisol, a stress hormone that regulates the release of norepinephrine, which, as was stated previously, controls emotional responses and tends to be higher in people suffering from PTSD. It is activated by the presence of stress, and it triggers the hippocampus to store the stressful input in long-term memory (1),(6). This is believed to explain why greatly emotional events can be recalled so vividly. More dangerous, however, can be highly traumatizing events, in which malfunctions may occur to the extent that memories are formed more strongly than normal, leading to flashbacks or other visual recollections (6). As she continues to murder and rob various men, she seems to do so with an air of stoicism. Supposing she was suffering from PTSD, such emotional numbness can be explained through the increased presence of hormones linked to stress, such as natural opiates. The levels of these opiates produced in PTSD individuals tend to be abnormal and have the effect of disguise pain, but for longer periods of time than would normally occur (6).
However, the portrayal of what happened on film and the perceptions of the police who interviewed her, the reporter who researched her life and the jury who condemned her to death (7),(3) lead to a different question regarding Lee's killing spree. What if she knew exactly what she was doing and planned each murder? Given her spotted record, it should come as no surprise that generally women convicted of homicide, in which the victim is someone other than a family member, usually have a pre-existing criminal record, and are considered to follow the male blueprint for criminal behavior (8). Given this information, we are forced to look at other biological factors that may have played a role in such a tragic expression of aggression. A possible explanation is the existence of abnormalities in the orbitofrontal cortex or in the amygdala, both of which have been cited to function abnormally in the brains of murderers and/or psychopaths (9),(10). The orbitofrontal cortex is part of the prefrontal cortex, which works to inhibit impulsivity (11) and has a role in the decision-making process. Individuals with noted anomalies in this area tend to have problems with controlling aggression (9) and the inability to correctly associate certain behaviors with being either good or bad. The amygdala, as mentioned above, regulates fear responses. Thus, a malfunctioning amygdala would most likely not produce the fearful and empathic responses (9) that would prevent a person from committing a crime such as murder and repeatedly so, thus causing aggression to be acted out without inhibition.
The simple factor of genetics may have also contributed to Wuornos predisposition of remorseless actions. Her biological father was reported to be a child molester who had an extreme case of antisocial personality disorder (7),(3). Individuals with personality disorders have been found to have lower cerebrospinal fluid (CSF) levels of 5-hydroxyindoleacetic acid (5-HIAA), which corresponded to high levels of aggression. It has been found that low levels of CSF 5-HIAA may be genetically inherited and thus may cause a susceptibility to aggression (12).
There is nothing that can unquestionably determine the actual cause of aggression and its more severe consequences. There are certain factors that can be observed, but the biological, psychological and social aspects of a person's life are intertwined so intricately that it would be impossible to fully understand or to answer the simple question of why. Science is a collection of observations, and the life and death of Aileen Wuornos is indicative of this.
1)The Neurobiology of Child Abuse, from Scientific American
2)Washington Post, article on Aileen Wuornos by her biographer
3)Crime Library , another story about Aileen Wuornos: The Myth and the Reality
4)Borderline Personality Disorder, from the National Institute of Mental Health
5)The Consequences of Violence Against Women, from Scientific American
6)Posttraumatic Stress Disorder, from the National Institute of Mental Health
7)Serial Homicide, Mind of a Killer: an Investigation of Serial Homicide-Aileen Wuornos
8)Wiley InterScience Journals, Journal of Clinical Psychology article on Homicidal Women
9)Into the Mind of a Killer, from Nature journal
10)Predicting Behavior, from Nature Journal
11)Society for Neuroscience, characterizing Violent Brains
12)The American College of Neuropsychopharmacology, the Neurobiology of Aggression
| Course Home Page | Course Forum | Brain and Behavior | Serendip Home |