I'll give my own reasoned and informed perspective on this issue. Since serial killers all have complex and disparate dispositions, motivations, modi operandi, backgrounds and childhoods, IQ, etc., I should preface this by saying that I am speaking in terms of the stereotypical, quintessential, or "beau ideal" serial killer, and not anomalous outliers (say, Richard Chase and others).
Serial killers are individuals born with a particular set of genes such that, when placed in a sufficiently abusive, dysfunctional, violent, neglectful, or emotionally austere or caustic environment, develop, as a sort of coping mechanism, abnormal fantasies and paraphilias and proclivities that are almost invariably of a sexual theme.
The theme may be invariable, but the smaller details and minutiae are highly variable. And so, what do Ted Bundy, John Wayne Gacy, Jeffrey Dahmer, Andrei Chikatilo, Luis Garavito, Gary Ridgeway, Wang Qiang, Moses Sithole, etc., have in common? Well, they all murdered people, of course. But they also all had sexual motivations for those murders. Moreover, the majority of their victims—with a small number of exceptions—were all, in some conspicuous fashion, similar to each other. Why? Probably for the same reason that most of the people you've ever dated or had sex with were similar in some manner or another—because that's what you've found sexually arousing or titillating.
But your sexual predilections presumably stopped at merely fucking or fantasizing about fucking that attractive, lascivious brunette you see everyday around town. Perhaps envisaging or engaging in the act of fucking her is enough to cause a penile tumescence; your pudenda's protuberance; an erection, dammit.
Some people are not content or adequately aroused by just the sex, however. Maybe they need further excitement. Perhaps they want that aforementioned attractive brunette to urinate in their mouth or maybe take a few slaps and rough her up a bit.
And still others may want to smother her to death, anally rape her corpse with the business end of a blade, cut her from the clavicle up, and then use her decapitated head for oral sex.
Different strokes for different folks, I reckon. But some folks are just very different.
And remember, it all starts out as an adolescent's erotic reverie. But the fantasy builds in intensity and poignancy, and then climaxes with ennui and satiety. Just the fantasy no longer elicits the same excitement as it did in its incipience. And the only excitement now takes the form of enacting the fantasy.
My hypothesis is that psychopathy is not a prerequisite for becoming a serial killer. A random serial killer may or may not be a psychopath. The reason he can murder without empathy is because he perceives his victims as the victims of his fantasies—not real, unfeeling, incorporeal. Just like you may imagine purposely hitting a made-up person with a car. Do you feel remorse? Probably not. It was just a character in your mind who doesn't really exist.
Serial killers, I hypothesize, desensitize themselves to murdering certain types of people through repetitive and incessant fantasy or mock murders. But murdering outside that demographic which populates their fantasy is not as easy, and may be emotionally difficult, as it would for a typical person.
Consider the case of Gary Michael Hilton, the Southern serial killer who murdered hikers but couldn't bring himself to kill a dog, as he loved animals.
That's part of my hypothesis, but it's far too lengthy to type it all out.
And here I'll be honest. Since my preteens, I have found it highly arousing to engage in thoughts of what I'll call "rough sexual behavior". Others may prefer the terms rape or sexual violence, but a rose by any other name still has pain-inflicting thorns, and nothing gets me off more than the thought of nonconsensual and aggressive sex. I dunno why, and I can control what arouses me no more than you or anyone else can—in other words, not at all. But I wonder why similar males with similar fantasies transmogrify from innocuous fantasizers to nefarious and ruthless victimizers. What initiatates this transition from contemplation to criminality? Or, rather what prevents it? It's fascinating, I say.
In psychology nature versus nurture is a seemingly unresolvable debate on many aspects of human behaviour.
Hah! What risible nonsense!
Within the politically correct, incredibly specious, needless and extraneous, self-important, patently leftist, and pseudoscientific domain of the soft sciences, the non-tendentious or politically unsullied observer will quickly notice the regnant and repugnant neo-Lysenkoism that social scientists obdurately espouse like a religion.
The standard social science model is its name, and the asinine twaddle that is social constructionism, Marxist malarkey, post-modernism, cultural determinism, and a farrago of more faustian flummery are its essential components.
In point of fact, there never was nor is there currently a nature and nurture debate. Just some informed natural scientists trying unavailingly to convince a population of pompous academic scientist epigones the errors in their confused and egregious notions of the unimportance of evolution and nature relative to society and exogenous environmental factors.
It seems theists take less umbrage with the theory of evolution than does the quintessential social "scientist" or humanities major.
"Chimps, gorillas, elephants, yeah they all evolved to adapt certain behavior. And, yeah, we can study this behavior via ethology and it can be described with precision via evolutionary explanations. But humans? No fucking way, man.
Because, like, if our behavior did evolve, yah know, and, like, our society is determined by evolved behavior and not vice versa, then, like, how could my egalitarian-Marxist-feminist antiquated 1960's political ideology remain valid? And my awesome math skills I acquired during my Women's Studies courses taught me that if x + y ≠ z, but you want it to, then rhetoric and obscurantism can make it equal z. So, like, if science doesn't corroborate my presuppositions about human behavior, then, you know, like, change the science or just ignore it. "
The soft scientist: an inexhaustible inspiration of side-splitting cachinnation and facile parody.
Any trait is not purely attributable to one or the other in my opinion.
I'm normally not very brusque and so do understand the difficulty with which it takes me to inform you that your opinion means sweet fuck all in science in particular and everywhere in general, especially when it is dead wrong and plain stupid.
So my having 10 fingers and 10 toes is not purely attributable to nature nor nurture? But some combination thereof? And the epidemiology of sickle cell anemia, which is almost exclusively found in people deriving from populations that historically lived in areas coinciding with high prevalence of malaria has to do with nurture? And the fact that—oh, I give up. G.C. Lichtenberg once put it thus:
We have no words for speaking of wisdom to the stupid. He who understands the wise is wise already.
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