Serial killers have long been a realm of interest to American popular culture. After all, people, strangely, are naturally drawn to things that terrify them. We are afraid of certain things but are intrinsically driven by curiosity. This is exactly why we hide our faces behind our hands but peek through our fingers. And the utter gruesomeness surrounding serial killers seems to be one of those things we can’t help but be fascinated by. This topic has, too, piqued the interest of psychologists, criminologists, and scientists who have searched to answer the question of how such violent humans have come into being. What is left are two schools of thought: are serial killers born with predetermined genes that destine them to become murderous or does their upbringing create homicidal tendencies? In other words, is it a matter of nature or nurture? The factors that aid in the making of a serial killer are much more complex than the nature-nurture dichotomy suggests and after years of continuous research and debate, the creation of such heinous beings has unequivocally been proven to stem from both biological predispositions and environmental influences, instead of the “one or the other” situation that many tend to simplify it to.
Though it’s tempting to dive straight into how such vicious individuals are created, it’s critical to first understand what defines serial killers and what makes them so incredibly different from other homicidal murderers. There has been considerable debate among criminologists about the proper definition of serial murder. The FBI originally defined serial murder as involving at least four events that take place at different locations and are separated by a cooling-off period, but in most current definitions, the number of events has been reduced, the FBI even following suit by lowering it down to three in the ‘90s (Johns et al.). However, the FBI’s definition has been faulted due to the exclusion of important factors, causing many people to instead adopt the definition put forward by the National Institute of Justice, where serial murder is defined as involving at least two different murders that occur over a period of time ranging from hours to years (Jenkins). A prominent distinction that separates serial killers from other murderers is their motives to kill. Normally, homicides are committed due to a variety of disputes, ranging anywhere from family affairs to gang violence to financial difficulties to matters between lovers or friends. 'A psycho killer, I should make clear, is not a regular murderer. A murderer has a vendetta, a nice specific personal thing against his victim' (Corin). Unlike other murderers, serial killers are only driven by instinct and a desire to kill, and in order to fulfill sexual desires and live out their fantasies, they’re driven to murder those who are total strangers to them. Grover Godwin, an expert in investigative psychology, collected data from 107 serial killers and their 728 victims from official sources like the FBI, local police departments, newspaper reports, and the Homicide Investigations and Tracking System (HITS) database. From his investigation, he discovered that nearly 90% of victims were complete strangers to the killer, only 3% were friends, and 1% were family members (Fox et al.). Not only do serial killers target strangers, but they also make sure they’re preying on the most marginalized members of society, like prostitutes, drug addicts, and the homeless because they’ll stand a greater chance of evading detection. As serial killer Samuel Little said to New York Times reporter Jillian Lauren, “I never killed any senators or governors or fancy New York journalists — nothing like that,” he told Ms. Lauren. “I killed you, it’d be all over the news the next day. I stayed in the ghettos” (Zraick). This largely explains why serial killers are able to get away with their crimes for so long because when detectives go to investigate the disappearances of missing people, there is no discernible link between the killer and the victim, making these mysteries practically impossible to solve.
The nature vs. nurture debate has one side believing that these extremely violent individuals do not grow into the shell of a killer but instead have predetermined genes that make up the chemical balance of their brain, body, thoughts, ideas, and most importantly actions. Over the course of several years, British neuroscientist Adrian Raine and his team analyzed the brains of numerous murderers and nearly all portrayed similar brain changes. The results showed reduced activity in the prefrontal cortex, the area of the brain which controls emotional impulses, and overactivation of the amygdala, the area which generates our emotions (“Are Murderers,” 2015). So it seems that murderers possess brains that make them more prone to anger and rage, while simultaneously making them less able to control themselves. Additionally, a report published in 2000 in Science Daily by Dr. Richard Davidson at the University of Wisconsin at Madison compared brain scans of over 500 people between those who were prone to violence and those who were considered normal (“Brain Study,” 2000). The normal group greatly contrasted with those who had been convicted of a murder with aggressive or antisocial disorders because the latter had almost no brain activity within the orbital frontal cortex or the anterior cingulate cortex whereas activity in the amygdala continued perfectly. If this is true, then these murderers must have been born with an entirely different genetic makeup than that of those in the majority of the population who are not violent. For example, Ted Bundy, one of the most prolific serial killers in American history, had a very normal childhood and grew up in a healthy household with supportive family members. Despite showing no signs of abuse or neglect, he was still presumed to have had low activity in his orbital frontal cortex and grew up to become one of the most notorious murderers of all time. His case is only one of the many that reinforces Davidson’s conclusion that although setting can definitely affect a serial killer’s thoughts, it cannot control their reactions to certain ideas that are a part of their DNA.
The other half of the nature vs. nurture dichotomy is firmly set on the idea that environmental factors play a more influential role in the making of serial killers than biological processes do. It’s not a surprise that the majority of serial killers had experienced a rough upbringing, including Charles Manson, John Wayne Gacy, and Richard Ramirez. In a study of over 60 serial murderers, researchers found that psychological and/or physical abuse was a prevalent trait of serial killers’ childhoods (Allely et al.). Although not all abused children become serial killers, and not all serial killers are victims of childhood abuse, it's still important to recognize that childhood physical and emotional trauma can be a greatly influential factor. In a group of 62 male serial killers, 48% had been rejected by a parent or some other important person in their lives (Allely et al.). In countless cases, serial killers faced extreme abuse as children and grew up in environments that fostered little nurturing or comfort. It’s obvious that kids who have a positive relationship with their parents are more likely to thrive emotionally. In contrast, kids who live in abusive and neglectful households on average have more behavioral and emotional problems, which in extreme cases can lead to serial murders. Some killers may also face bullying and teasing from their peers. For instance, serial killer Ronald Dominique was bullied profusely for being gay. Years of subjugation resulted in him housing many negative thoughts regarding his sexuality. Dominique raped and murdered more than 23 men, most of whom were male prostitutes. These violent crimes against gay men, members of his own sexual community, is most likely a result of the severe bullying he faced as a teen for being a homosexual himself. Another example involves serial killer Edmund Kemper who suffered physical and emotional abuse from his mother. Not only was he constantly ostracized in his family but he was also forced to sleep in the garage, oftentimes being restricted to food and water by his mother. Due to this, Kemper developed an intense hatred for women and brutally raped, beat, and tortured ten women, his mother and grandmother being two of his victims. The environmental and social aspects of a person’s life have considerable consequences on behavior, and in cases of extreme abuse and social ridicule, these factors can aid in the making of serial offenders.
When taking a glimpse into Jeffrey Dahmer's childhood, you’ll find that he actually used to be a fun and active child who his father described as, 'Very exuberant, he liked to wrestle, liked to run around, ham it up for the camera and he liked to play with kids and get together with them' (Rogers). These are not characteristics of a serial killers who scientists say are born with this gene of aggressiveness. Dahmer had been a normal child until his family moved, relocating three times before settling down in Bath, Ohio. After the move, his parents noticed that their son had become shy and antisocial. Dahmer then began collecting roadkill to dissect in experiments. The dead carcasses gave him a feeling of comfort, pleasure, fulfillment, and emotional release that his family couldn’t provide. Criminologists and social behavioral psychologists formulated the idea that repeated psychological trauma during the early stages of growing up can cause a child to seek relief through acts of violence such as killing small animals. They did this because, against their parents who had control over their lives, they felt powerless. Since these children did not have control in the household, they resorted to killing small animals in which they could exert their dominance and power to do anything that pleased them (Fox). But they didn’t just limit it to animals. After all, this twisted fascination with power would only expand over time, reaching into their fantasies, and pretty soon, turning those fantasies into a reality that only they could control. A great example would be Jeffrey Dahmer growing up feeling rejected by his parents and, in turn, kept the violent homosexual thoughts to himself. Dahmer fantasized about having a male sexual partner, but in his thoughts, he received pleasure not only by having intercourse but also by killing his partner. Without a proper relationship to model after in the household, many of these murderers turn to their fantasies as a safe haven that they can eventually recreate into a controllable reality.
In 1993, a notable breakthrough occurred with a family in the Netherlands where all the men who had a history of violence lacked the same gene. This gene produces an enzyme called MAOA, which regulates the levels of neurotransmitters involved in impulse control (“Are Murderers,” 2015). It turns out that if you lack the MAOA gene or have the low-activity variant, known as the warrior gene, you are predisposed to violence. About 30% of men have this so-called warrior gene, but whether the gene is triggered or not depends crucially on what happens to you during childhood. Jim Fallon, professor of psychiatry at the University of California, was shocked when he examined his own brain scan and realized it contained all the markings of a psychopath. He then researched his ancestry and discovered a large number of murderers in his own family tree tracing back generations. That raises the question: how is it that Fallon holds all the genes linked to violent psychopathic behavior, yet isn’t a psychopath at all? His answer to this is that he escaped a potentially brutal fate by growing up with a happy and healthy childhood (Taylor). 'If you have the high-risk form of the gene and you were abused early on in life, your chances of a life of crime are much higher. If you have the high-risk gene but you weren't abused, then there really wasn't much risk. So just a gene by itself, the variant doesn't really dramatically affect behavior, but under certain environmental conditions, there is a big difference (“Are Murderers,” 2015).
For generations, experts in all sorts of fields as well as the general public itself have sought to understand how serial killers have come into being. Scientists vouch for nature, claiming that genetics is the key role in determining who becomes a serial killer, while criminologists and psychologists argue for nurture, stating that critical life events such as abuse and abandonment create the setting and foundation in which serial killers grow into sadistic mass murderers. Though both arguments are strongly proven and explained through research and statistics neither is individually the answer to why serial killers exist. This very issue has been a question of hot debate for ages, but even after years of continuous research and dispute, it’s impossible to arrive at one definite answer. In reviewing the evidence of both explanations I have found that it is a mix of both genetics and cultural upbringings. Though many humans must deal with violent situations as children and experience horrific events many do not become mass murderers. It is true that many children who are victims of abuse become violent in their adult lives but to cross into the category of a serial killer one must be born with a different biochemical makeup. In my conclusion, nature does choose what traits we are born with but at the same time, these traits cannot be exposed without a mechanism that triggers these individuals to commit these horrific crimes. Without the alignment of both natural genetic defects and the cultural nurturing in which humans are brought up, serial killers cannot become vicious killers.