As tempting as it may be to draw up a list of personality characteristics of serial killers, there is no one-size-fits-all formula for serial killer personalities. What basis is there, if any, in the secretive, remorseless serial killer stereotype depicted on screen?

Recently on The Science of Personality, cohosts Ryne Sherman, PhD, chief science officer, and Blake Loepp, PR manager, spoke with Katherine Ramsland, PhD, professor of forensic psychology at DeSales University, about the personality of serial killers.

“I did not set out to be an expert on serial killers,” Katherine said. Nevertheless, she has appeared as an expert on more than 200 crime documentaries and written more than 1,500 articles and 69 books, the latest of which is I Scream Man: A Nut Cracker Investigation. She also collaborated with Dennis Rader, the BTK Killer, on his autobiography.

Let’s dive into this fascinating discussion on debunking myths about the personalities of serial killers.

Personality Characteristics of Serial Killers

There’s no personality type for serial killers, no matter what crime dramas want us to believe. Simplifying serial killers with false assumptions can be dangerous. One such assumption is that serial killers have a concrete set of identifiable personality characteristics. They don’t.

What they do have in common is meeting the FBI’s definition of a serial killer. “You’ve murdered at least two people on two occasions. That’s it,” Katherine said.

Serial killers are far more complex than what the media depict. Serial killers have a wide motivational spectrum, and their motivations, not necessarily the fact of killing, reveal personality characteristics. Their motivations might be to seek fame, thrills, or sex, to pursue a delusional idea, to eliminate witnesses, or many other objectives. Even within a small framework such as serial killer shooters, there are a range of motives, methods, weapons, and other differences. “We’ve documented over 5,000 serial killers around the world and from different eras—so they’re obviously going to have lots and lots of differences,” she explained.

The story of historical serial killer Belle Gunness illustrates the importance of difference in motivation. Gunness was a late-19th-century Norwegian American pig farmer who advertised in newspapers for husbands and murdered them for their money. She didn’t kill primarily because she enjoyed killing but because she wanted to obtain the men’s wealth. Her motive was greed, not violence.

All we can really say serial killers share is a definition. But is there any basis to the stereotype of the psychopathic serial killer?

Serial Killers and Psychopaths

The relationship between serial killers and psychopaths looks exactly like a Venn diagram. Not all serial killers are psychopaths, and not all psychopaths are serial killers, but some are both. The lack of empathy and remorse that most people imagine typifies a serial killer is sometimes, but not always, true. When psychopathy and serial killing intersect, experts often find the killer shows no empathy or remorse.

Another myth about psychopathic serial killers is that they enjoy killing. Again, some may, and some may not. In the case of mob assassins, one might murder dozens of people under orders with indifference, while another might find that getting hired to do some hits coincides with what he already likes to do (such as contract killer Richard Kuklinski).

Cubing

In her 12 years of communicating with Dennis Rader, the BTK Killer, Katherine observed a phenomenon called cubing or compartmentalizing. She watched Rader rapidly shifting personas depending on his circumstances to create different impressions on different people.

This is called cubing because the sides of one cube are all part of the same shape, but only one face shows at a time. Psychopaths, who tend to have shallow emotions and no allegiance to truth, can switch seamlessly to any side of the cube: spouse, parent, employee, stalker, or serial killer.

Cubing can be a great asset to a serial killer. Rader showed psychopathic versatility in shifting quickly to the face he needed in any given situation. “They don’t care if they’re deceiving you or inconsistent as long as you buy the face they’re showing you today,” Katherine said. Whereas most of us have a commitment to our sense of identity, psychopaths shift identities to get whatever it is they want.

Serial Killer Nature Versus Nurture

What makes a serial killer, genetics or life experiences? The age-old nature versus nurture question is a challenging one when applied to serial killers. Katherine’s answer is that it depends. “For every given individual, how much is a measure of their inborn temperament versus things that happen to them is going to be different,” she said.

Nobody is born a serial killer, just as nobody is made into one. It’s a combination of factors. Human nature is too complex to dictate that, all other things being equal, two people will react the same way to the same stimuli. Having an abusive parent, for instance, wasn’t the sole cause of anyone becoming a serial killer (although it certainly may have been an influencing factor). Having a disposition to psychopathy doesn’t cause serial killing either.

“It really is a media-generated notion that there’s a profile of a serial killer,” Katherine reiterated. “What profile? There isn’t one.”

How do we identify a serial killer, then? Do they all have three phones, tend to disappear, and keep a hammer near the kitchen sink? No, identification is extremely difficult because every suspicious, red-flag behavior could have a benign explanation.

Generalizing about serial killers fails to recognize the ambiguity of the human condition. A high proportion of serial killers do have some of these characteristics, however:

• Many serial killers are psychopaths. They show no empathy or remorse and have no core values or internal consistency.
• Many serial killers are predators. They can be secretive and deceptive, and they actively search for victims.
• Many serial killers have a fantasy life. They imagine their crimes in advance and enact them in the real world to activate their mental reward mechanisms. They are often self-delusional.

Katherine made it very clear that there are always exceptions to the above characteristics and that it can be dangerous to apply a false profile to serial killers. “Human existence is more complicated than our formulas allow it to be,” she said. “They do a disservice not only to our understanding of offenders but also to people who are potential victims. I prefer the truth.”

Listen to this conversation in full on episode 61 of The Science of Personality. Never miss an episode by following us anywhere you get podcasts. Cheers, everybody!