Serial Killers: To Be Or Not To Be

“We serial killers are you sons, we are your husbands, we are everywhere. And there will be more of your children dead tomorrow” (Ted Bundy, 1989). Theodore Robert Bundy was one, if not THE most infamous, prolific serial killers that we have on record (that was caught, of course) for the murder of 36 women, or as Bundy confessed, though, it is also recorded that Bundy himself hinted that there were more, much more. So what makes serial killers so fascinating? Well, it isn’t necessarily “What?” if anything, it’s “Why?” Why do serial killers do what they do? What makes them do what they do? Are they born serial killers or are they made serial killers? This is a question of nature versus nurture. Nature refers to all of the genes and hereditary factors that influence who we are—from our physical appearance to our personality, that serial killers are born. Whereas nurture refers to all the environmental variables that impact who we are, including our early childhood experiences, how we were raised, our social relationships, and our surrounding culture; that serial killers are made. As more and more forensic psychologists take on the task of trying to figure out the inner workings of serial killers, it wasn’t up until 2007 when one of the first theories was presented to the public. The theory that serial killers are born with genes CDH13 and MAOA-L as opposed to the theory that serial killers are products of abuse and other sexual, psychological, and physical means. All of which are the keys to the psychopathic and sociopathic tendencies that we see in criminals and serial killers.

The MAOA gene (MAOA-L) encodes monoamine oxidase A, which is an enzyme that degrades dopamine, serotonin and norepinephrine. Dopamine, a neurotransmitters in the brain that plays a major role in the motivational component of reward-motivated behavior in the brain. Serotonin, or 5-hydroxytryptamine, is a transmitter that is often contributed to the feeling of happiness, though, serotonin’s functions are much more complex than simply, “happiness.” And norepinephrine, or l-Norepinephrine, is a hormone that functions as a neurotransmitter in the sympathetic nervous system. However, if a mutation were to happen, a MAOA mutation would result in a MAOA deficiency and in turn, would result in an excess of monoamine transmitters, causing excessive impulsive behaviour including hypersexuality (addiction to sex), sleep disorders and extreme mood swings as well as a tendency to violence. This theory would support the concept that serial killers are born, seeing as following this discovery, it was reported that the MAOA-L variant is actually more common than you would think, occuring in about 40% of the population, mostly males. MAOA-L has since been linked to aggression as the “warrior gene”.

The MAOA-L gene consists of two subgenes: the DAT1 gene and the DRD2 gene. Both of which were studied in the first national study that provided propelling evidence that the DAT1 gene and the DRD2 had a link to aggression and violence in criminals. The dopamine transporter (DAT1) acts as the mediator in the activation and inactivation of dopamine in the brain, like a switch. The D2 dopamine receptor, on the other hand, is a G protein-coupled receptor that is located on dopaminergic neurons and is most known to be involved in the reward-mediating pathways. The receptor is then coded by the DRD2 gene, which is involved in functions such as hormone production for example. Studies of the DRD2 has since come to show that if someone were to have a DRD2 variant, he/she would be at a higher risk of committing violence as a delinquent but only in instances where the individual suffered from some sort of stress factor such as family issues (divorce, etc.) and/or failing school can often lead to the individual to act irrationally and violently.

Studies have also found in a study that serial killers have a 5-10% reduction of gray matter around the region in the brain where emotions are processed. This is significant because the size difference is pointedly prominent in the amygdala, a series of small glands in the brain that have been linked to empathy and studies have shown that people with excessive or “oversized” amygdalas tended to be super-altruists whereas people with “undersized” amygdalas tended to be empathy-deficient and can be linked to sociopathy. Likewise, the neural circuits connecting the limbic system with the frontal lobe are found to be far less active in the brain of criminals and serial killers. The damage to the frontal cortex that is involved in the inhibition of inappropriate behavior and the regulation of emotions can result in a lack of empathy and an increase aggression, impulsivity, and violence. However, this theory can be argued against as there are cases where people with undersized amygdalas aren’t serial killers but many that do suffer from a lack of empathy and are often much more antisocial and violent. Not all sociopaths are serial killers.

Cadherin-13 (CDH13), a unique glycosylphosphatidylinositol-anchored member of the cadherin family of cell adhesion molecules, as recent studies show, might also have a link to aggression and violence. Though CDH13 is most commonly associated with ADHD and autism, it has been recently identified to play a part in many psychiatric conditions such as depression, substance abuse, autism, and aggressive and violent behavior. In a recent study with mice, scientists declared that they were unable to find any CDH13 variants associated with violence, though it was suggested that a CDH13 deficiency may impair the hippocampal-dependent learning process that underlies the habituation to consecutive behavioral tests which only really proves the fact that CDH13 can be linked to ADHD and autism. Until further studies are made about CDH13, we cannot say for sure if CDH13 plays a part in the development of what might make someone a criminal.

However, at the same time, based on the fact that 68% of serial killers suffered from some sort of childhood abuse or trauma or that serial killers are a largely American phenomenon (according to the FBI, a whooping 67% of the world’s serial killers originate from the United States) strongly supports the “blank-slate” idea that when we’re born we’re born with a “blank slate” up until a cultural or learned aspect to serial killing is introduced. This idea would support the nurture argument. Although it is true that a large amount of serial killers suffer from abuse as children, some, on the other hand, as Ted Bundy claimed. He knew he was different, he knew he was different from the start. Some may argue that the reason that drove Bundy to become the serial killer he is renowned for today is because he was “lonely” as a child, seeing as he claimed that he felt that his siblings got most of the attention which resulted in him window peeping which eventually resulted in his serial killer career. Although loneliness might’ve played a part in what made Bundy the man that he became, he also had a strained relationship with his father and was often bullied at school, though, those occur commonly in our generation today. All we know is what Bundy told us, though, we may never know why he did what he did.

Ultimately, there is still a lot of speculation when it comes to nature versus nurture and whether or not someone can be born “good” or “evil” or in this case, if you can be born a serial killer or not. It is safe to say, with what information that we have at the moment, that there’s a big chance that serial killers are born AND made. Much like the twin experiment last year, nurture can play a big part in the development of the brain, especially so in children but nature can as well. As more and more studies are made, we may or may not be to finally break the barrier between man and his mind and we might be able to finally figure out how the brain works and further our understanding of humans. Who knows? We may be able to screen for sociopathic tendencies in the future much like the concept of screening for genetic diseases for pregnant women. Until then, steer clear of white vans.