Murder, Narcissism, and the Limbic Ring: The Neurology of The Serial Killer

Reference & EducationCollege & University

  • Author Robert Depaolo
  • Published October 29, 2022
  • Word count 3,113


This article offers the opinion that serial killers are driven by neuro-behavioral drives that might be coupled with socio-intrapersonal dynamics but in and of themselves are too strong, the killer too unable to describe his motives to engage in such compulsive acts of violence to have purely psychological causes. Since all behaviors and motives ultimately derive from brain circuit interactions the assumption here is that faulty inter-connectivity in the limbic system of the mid brain is a primary driving force behind serial murder.


Many clinical professionals, as well as forensic analysts have discussed serial murder in what might be called quasi-Freudian terms. For example, one prevailing belief is that penetration by knife and other means, symbolizes the sex act. The implication is that the killer has somehow paired aggression with sexual relief. Indeed, popular movies and TV programs like Criminal Minds present that as fact.

Another widely held belief is that the sex act is not for gratification per se but an attempt to humiliate the victims, who are usually female - with exceptions such as in the cases of Dennis Rader (BTK killer), John Wayne Gacey and Jeffry Dahmer, whose sexual attractions were to young males.

One would think the true motives behind such acts could be determined by interviewing the killers - several of whom were fairly forthcoming in discussing why they did what they did. On the other hand, try as they might, neither the investigators, clinicians nor the killers themselves were able to determine why these acts occurred, and more specifically, why they continued to engage in such horror on a continual basis.

Some theories have been offered. Ted Bundy was supposedly reacting to rejection by his first lover by punishing young women who looked like her. He was also presumed to harbor strong resentment toward his mother who bore him out of wedlock, which fueled long-standing anger and insecurity over his illegitimacy. A similar motive was attributed to Gary Ridgway, the Green River Killer, who began to murder prostitutes following his wife's rejection and request for divorce.

In many of these cases, including those of Edmund Kemper, Ted Bundy and Gary Ridgway, some sort of rejection by women (including by their mother through harassment or humiliation) seem to have been potential triggers. On the other hand, that was not true of Gacey, Dahmer, Albert DeSalvo (the Boston Strangler) or Dennis Rader, whose wives and mothers were supportive.

Fact is many men have experienced rejection, bad parenting and other potential stressors without killing incessantly. That seems to indicate that the most central causation might not lie solely in the killer's background or family dynamics. That might explain why none of the serial killers - even those who were forthcoming could determine why they murdered people. Nor could they determine why their acts were compulsive and based on a recurring need, as with the sex drive or the need for social connectedness and nurturance.

With that in mind, it is possible many, if not most of the apparent casual factors in their actions, for example rejection by females, confused sexuality, bad parenting and social detachment might be coincidental. This seems to apply to both Ted Bundy and Edmund Kemper. The former was rejected by a woman and was devastated to find out he was illegitimate. However, aside from the fact that many men experience the same occurrences and do not kill over thirty women, Bundy was rejected at age 20 and discovered his birth circumstances in his teens, yet tortured cats as a ten-year old and placed knives around the bed of his aunt Julia at age 3 to frighten her. Meanwhile, Kemper's mother was abusively critical over a long period of time in his youth. That might have given rise to his penchant for murdering co-eds. On the other hand, his first act of murder, for which he was placed in an asylum was perpetrated on his grandparents with whom he had a good relationship. For that reason, it seems that at least in those instances the social/interpersonal version of causation is contradicted by actual timelines and events.

Another seldom mentioned factor is the intensity of the drive. To perpetrate their crimes, all these men had to go to extraordinary lengths. Bundy had to spend time stalking, peeping into windows, hanging around late at night to the point of exhaustion. Despite on many occasions failing to secure his prey he repeated the activity over and over again for years. Dahmer stalked, seduced and drugged his victims and went to the trouble of dismembering them and burying them in his own home - as did Gacey. The sheer effort involved in these acts suggests the drive to combine sex with murder, social need/fear of abandonment was so intense as to suggest the cause was rooted, not in social or interpersonal angst but in something more biologically compelling: something sub-cortical that bypassed or at least overrode the critical, logical scrutiny of higher brain centers.

As for the Freudian element, his own theory offers a contradiction to current analyses. Freud believed two forces within the personality: eros (referring to a life giving energy source) and thanatos (referring to the death instinct and energy-depleting tendency to give up and destroy self or others) were in opposition to one another. To kill with a knife as a means of obtaining sexual gratification would not be seen in psychoanalytic terms as a real possibility. Indeed, Freud might have questioned how sex and death could occur in a pairing. Add to that the pure physiology of the sex act, whereby reaching a climax is always preceded by a state of pleasure and relaxation. Killing someone after feeling good makes no sense in a purely physiological context. It is, in a natural sense incongruous, assuming the brain is wired normally.

That leads me to another conclusion - that serial killers have faulty neurological wiring that enables sex, neediness, fear of abandonment, aggression and dominance dynamics to be integrated into repetitive murderous motives. That doesn't mean the killer has a neuropathology - most of the studies of their brains indicated normalcy. It does mean that sites devoted to seemingly disparate behavioral and emotional functions can, in certain circumstances be hooked up into a horrendous self-contained network of sex, social dependency and violence; a network whose arousal levels can only be relieved by acts combining and satisfying all those needs at once. Such a scenario might explain how multiple drives could come together to produce a collective "id" - driven behavior pattern - and a monster.

Neuro-behavioral Unification...

The way in which this could occur would be by having permanently high basal arousal levels obliterate the capacity to discriminate between self and other and right and wrong, and by obliterating the distinction between the drives for aggression (nihilism) sexual gratification, sucorance, and social connectedness in a way normal society deems pathological. It would explain why Dahmer and to an extent Bundy were inclined to kill to satisfy their sexual needs through necrophilia. Their acts provided collective satiation involving sexual release, dominance and unwavering social connectedness through relations with a dead person, who could not leave, reject or disappoint. It could have been an unholy triad galvanized by chronic hyper-arousal in the reciprocally influential circuits of a part of the brain known as the limbic system. This network, oftenrefereed to as the "reptilian brain' provides emotional impetus for purposes of maintaining survival. While it is connected tohigher brain centers it does not provide cognitive labeling, parsing and analytic capacities. It is a circuit devoted to sheer urgncy and because it its sheer power its arousal levels must in normal circumstances be controllable so that activation is followed fairly quickly by de-activation or "resolution," if resolution does not occur it will tend to produce disastrous behavioral results, particularly in the context of rule-driven human society.

Hyper arousal - which is often a feature of trauma is designed by nature to prevent parsing of actions and moods. Since it is a survival mechanism it must produce instant, urgent and single-track behaviors. That in itself would tend to preclude the kind of parsing that allows for consideration of self and other, for empathy and guilt, and for what psychologists often refer to as "good gestalt"...or figure ground perception. Hyper arousal creates blind-side perception, and since some sort of emotional survival is involved n high activation states that creates an emphasis on self-preservation to the exclusion of the feelings of others.

The problem is, unlike a normal person, serial killers ostensibly have no shut down mechanism, i.e. diminished capacity for neuropsychological resolution. They can conceal hyper arousal fight it, perhaps resist it for periods of time but it is a powerful drive that will tend to win out by sheer force. Normal people have intense experiences but have control over arousal levels so that resolution occurs following a return to equanimity. If there is no resolution and, if arousal is chronic in the context of a "high maintenance" personality all bets are off. In such circumstances the person might not be psychotic but is still quite fragmented neuropsychologically.

The Vicious Circle...

The site where this pathological integration of drives (spillover) could occur is in the limbic system. Interestingly, just as the killer's motives and triggers seem to revolve collectively around an entwined circle of needs pertaining to sex, dominance. aggression, fear of abandonment, objectification of the victim and what amounts to a fairly permanent fight/flight mentality, so is the limbic system organized in a circular configuration. That arrangement allows for the possibility of one site influencing another through a spillover occurance.

Neural spillover is a fairly common feature of brain dynamics. For example, one speech center (Broca's area) is located in the fronto-parietal lobe of the cerebral cortex. It is situated next to a motor strip that controls fine motor responses of the tongue, fingers and hands. The fact that we gesture manually when we speak - especially in emotional circumstances is because one network spills over to another. In that case, arousal diminishes the capacity to parse behaviors. In the normal person temporary emotional arousal leads to collectivization of behaviors while diminishing discriminatory, parsing capacities followed by a return to an analytic cognitive state enabling us to tell right from wrong. sex from anger etc. On the other hand, chronic arousal, in the limbic system (reflected in activation of the sympathetic nervous system pathways) increases the likelihood of unchecked behavioral pathology. Compulsions result and the capacity to separate the drives for sexual gratification, self-preservation, aggression and general social neediness are blurred.

The limbic system is ideally suited to neural spillover and the melding of aggression, sexuality, fear, social isolation, neediness and self-concern into singular behavior patterns. In such instances, the killer feels constantly threatened, not necessarily in the physical sense but perhaps in response to unmet needs in the sexual, and social areas. The fact that the killer is so vulnerable to such feelings is likely because of a fragile central nervous system that is highly stressed intolerant.

One interesting aspect of that hypothesis is that many clinicians have asserted that psychopaths tend not to have anxiety or depression and are virtually emotional blank slates. Having worked with sociopaths this clinician noticed that in many instances the mask-like obliviousness to feelings of fear and other emotions is based not on an absence of emotion but on adaptive blunting and the singularization of their needs due to chronic arousal levels. In effect, they have a narrow, hyper-focused emotional panorama that merely looks like emotional detachment.

The layout of the limbic ring is interested in that regard. It contains the potential for love, anger, aggression, territoriality, fear, sexuality and general neediness, including the tendency to expect affection and nurturance from caretakers. These are centers for various survival functions. One network, the amygdala is concerned with rage and territoriality. Another network, the hypothalamus is concerned with sexual gratification, maternal behavior patterns and appetitive drives. A structure known as the hippocampus is concerned with memory consolidation and the septal region has something to do with the registration of pleasure responses. Aside from the fact that these sites are proximal to one another there are two reasons to suspect their pathological unification can lead to the actions of a serial killer. For one thing, there is a neural pathway called the stria terminalis that connects the amygdala and hypothalamus through a relay station known as the thalamus. Since the hypothalamus is also concerned with appetite that connection makes it possible for aggression, fear, flight, fight, appetite and sexual drives to be unified. In that context, it is interesting to note that some serial killers have indulged in cannibal-like behaviors, including Bundy's biting the leg of one victim that led to his conviction for the Florida murders and Dahmer's storing body parts in his refrigerator. While Bundy in particular fooled people with his "social cool," his spontaneous, out of the blue periodic explosiveness and intense, depression- Inducing jealousy suggests his arousal was at a constant high pitch, even if well disguised. In fact, a fairly clear indication of that can be found in the book The Phantom Prince by Bundy's girlfriend Liz Kendall. In this book Liz' daughter Molly recounted an experience with Bundy, in which during a game of hide-and-seek, Bundy had taken off his clothes and slipped under a blanket. Upon discovering him, Molly (then 7) saw that he had an erection and because it had a reddish color, she asked him if it hurt. At that moment Bundy morphed. In Molly's words: "He stopped laughing and looked at me. Something was very wrong. The pupils of his eyes had become tiny, almost as small as the point of a pencil. One was looking in a slightly different direction from the other." The spontaneity and sudden manifestation of sympathetic nervous system reactivity juxtaposed on sexual arousal seems to indicate that there was an entrenched, fairly automatic co-reaction involving sex and aggression within Bundy's brain that seemed limbic-Reflexive and bypassed cognition and here and now experience.

Not all serial killers experienced trauma, but most, including Bundy, Ed Ginn (the morbid inspiration for the movie Psycho), Edmund Kemper, John Wayne Gacey, and Ridgway - whose mother engaged in acts of sexual provocation toward him, did experience severe emotional abuse of one sort or another in childhood. All of that would, at the very least have created an anti-social mindset; producing a detachment from society that could produce resentment, rejection of norms and need for retaliation to restore a sense of self equilibrium. However, once again, many people have similar experiences and few act out in the way these men did. That seems to suggest an awkward juxtaposition of experience, stress intolerance and neural re-wiring occurred to render them uniquely dangerous.

That raises another question that has vexed clinicians and law enforcement personnel for years. What if there was no trauma to speak of - at least the kind so severe as to create constant rage? In order to explain this requires some discussion of stress tolerance. Not all people react in the same way to duress. The central nervous systems of individuals vary in their response to input. Introverts tend to avoid high stimulus conditions because their arousal levels in response to stimuli are not only more intense but have a longer duration. Psychologist Hans Eysenck referred to these types as being tender minded. Similarly, Pavlov wrote that some people susceptible to psychopathology have such stimulus intolerance that they frequently experience a neural shut down - which he referred to as protective inhibition.

Obviously, childhood experiences could come into play because children are by definition stress intolerant. They have neither the cognitive parsing capabilities, the hormonal defensive boost of adolescence nor the refined defense mechanisms to cope with stress. Thus, early experiences can create bizarre combinations of behavior and mood. However, once again. Even with children there are variations in temperament and stress tolerance.

Here, it is suggested that serial killers somehow experience chronic arousal resulting from a combination of experience and the neurological integration of from flight/fight, appetitive, sexual and dependency needs to form a vortex of horror so derivative of limbic functions that they themselves have no idea how to describe or control their impulses.

The question is whether this ostensible mal-connectivity is related to nature, nurture or some combination of both. This is a complex issue because in child development vertical (associative) pathways in the brain are formed in a natural template while other cross-grid (conceptual) pathways seem to be formed in part through learning experiences. Absent a capacity to monitor neural circuit interactions (a difficult task, considering there are billions of interacting pathways in the human brain) it would be difficult to predict or prevent the emergence of a serial killer.

On the other hand, if neural causation is involved aggressive behavior patterns will tend to show up in childhood, perhaps unrelated to experience. That could certainly have diagnostic and prognostic value. By no means would this exempt the serial killer from responsibility because while sub- cortical (limbic) circuits would be running the show - at least periodically, the higher brain centers (i.e. the cerebral cortex) would still be intact and capable of parsing under the right set of circumstances. Indeed, even if this model is feasible, there might be many individuals who are id-wired but who somehow manage abstain from serial murder; perhaps through supportive families, vocational pursuits that take up time and effort, or because they have creative outlets through which to channel fantasies into abstract, prosocial endeavors. It is a complex issue but ultimate resolution to this problem would seem to require taking both experience and neuropsychological factors into account.


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Robert DePaolo MS Clinical Psychology, Retired former Adjunct Prof Psychology NH University System, practitioner of clinical psychology, neuropsychology and educational psychology and author of Bundy: A Clinical Discussion of the Perfect Stor

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