Another day, another bad EvoPsych article


Do you enjoy unsupported premises and unwarranted conclusions? Then you’ll love this article about how serial killers are the product of evolutionary forces.

(Warning: evil cat tried to disrupt this recording and makes a few random appearances.)

Transcript down below.


This is a video about a controversial and unpleasant topic which I fear is going to get demonetized or even blocked by YouTube, so I’m going to preface it by saying I’m going to use a euphemism: it’s about bad people who serially unalive lots of other people, and I’m going to refer to them as SKs. You’re smart people, you can figure it out. You’re smarter than YouTube, anyway.
I was sent an article about a juicy and popular topic, the psychology of SKs, and at first I thought my usual audience wouldn’t be particularly interested in this subject, but as I read on…yikes, it’s about goddamn EVOLUTONARY PSYCHOLOGY. Long time viewers might know that I really, really detest evo psych, and this particular article pushes all my buttons hard, so now of course I’ve got to talk about it.
First allow me to explain that I have no problem at all with the disciplines of psychology and sociology, and I think they could have valuable things to say about SKs…a topic which is also of genuine concern to modern society as a whole. So please do study and analyze the behavior of psychopaths, as unpleasant as it is. You go, psychologists, you can tell us something about what leads people to such destructive behaviors and maybe reduce the likelihood of that happening.
This study is not particularly helpful.

It’s titled “Sex differences in SKs,” and that’s a good start. From what little I know of these crimes, sure enough, I’m aware of sex differences there. Many more men than women are SKs, and from lurid pop culture stories I have the impression that males (MSKs for short) are more violent and bloody, while FSKs are more likely to use poison. That’s a real difference, it seems, so well worth analyzing. We should first look to see whether my impressions are at all accurate, of course, and the paper confirms them.

This is a table of data gleaned from reports of 110 killers, and there’s some real information here, even if it is rather horrifying. There are genuine statistical differences between MSKs and FSKs. Men tend to go after strangers, women hurt familiar acquaintances. Men favor more violent direct attacks, women do use poisons more often, but asphyxiation is popular with both sexes. It’s a grimly fascinating table. It is also the entirety of the data presented; most of the paper is about statistical analyses and speculation of the numbers you see here.
If you’re like me, you probably wonder about the causes of these differences. I would guess that physical differences are significant: men are generally larger than women, making it more difficult for FSKs to succeed in face-to-face physical conflict with a man. There are significant cultural differences between men and women: most women are brought up to be more passive and obedient to the whims of the patriarchy, and I’d expect psychologists to dig deeper into the motivations and reasoning behind their acts (hint: they don’t). There is a pattern here, it’s going to take more than tabulating data to get to the root of the problem.
So I was gobsmacked to read a summary of the study in which one of the authors jumped immediately to a ridiculous assumption.

While there is considerable public interest in serial killers, Harrison said there has been little research on these crimes, possibly because serial killers are relatively rare. But while working on a previous study, Harrison started to notice a difference between male and female serial killing patterns that she was interested in exploring.
Harrison said that because humans lived as hunter-gatherers for about 95 percent of history, these ancient roles could help explain these differences.
“Historically, men hunted animals as prey and women gathered nearby resources, like grains and plants, for food,” Harrison said. “As an evolutionary psychologist, I wondered if something left over from these old roles could be affecting how male and female serial killers choose their victims.”

WHOA. They’re comparing MSKs to hunters, and FSKs to gatherers, as if their crimes are somehow similar to hunting meat or collecting berries? Are SKs usually eating their victims? The table doesn’t even mention cannibalism.
OK, I thought, maybe this is just sensationalist hyperbole said in a press release, but surely the source article would be more sober and considerate of the evidence. Nope. It jumps directly to the idea that the reasons for the differences can be found in evolution.

In the present article, we put forth the argument that MSKs are theoretical “hunters” of victims and FSKs are theoretical “gatherers” of victims. That is, MSKs more frequently kill strangers they stalk, traveling distances to “hunt” and kill. In contrast, FSKs more frequently kill those around them, figuratively “gathering” victims who are familiar to them, staying in one place to kill. These differences may stem from sex-specific tendencies derived from labor divisions in the ancestral environment whereby men hunted animals as prey and women gathered nearby grains and plants for food.

Ugh. Evolutionary psychology.
While I might agree that, in the evolution of humans, women have been constrained by the impositions of pregnancy (biological) and childcare (cultural) which limit mobility and leave men to be the wide-ranging hunters, that this difference is at all useful in explaining the behavior of pathological individuals is a huge stretch. It’s also entirely superfluous, explaining nothing. I have several objections.
1. There is no reason to assume that damaged, pathological individuals are at all representative of the processes that operated in normal, healthy societies, modern or ancient. The extrapolation from ancient hunter-gatherer communities is unwarranted.
2. For this to be an evolved trait, it would have to be heritable. Are there pedigrees of SKs that show the existence of whole lineages of these individuals?
3. Is there any adaptive significance to the method of execution? Why should we consider evolutionary psychology, a panadaptionist program, to offer anything in the explanation of these behaviors?
4. I think the authors would not argue that SK is in itself a heritable property, but that the mode of expression is a consequence of sex differences. But then why is SK a useful property to study at all, when the pattern of sex differences is already observable?
5. The most damning indictment of this study is that is drawn exclusively from news accounts of SKs in the United States of America between 1856 and 2009. So not only are they looking at extreme behaviors from fringe individuals, but they are basing it entirely on one oddball culture, and they’re drawing conclusions from indirect, biased sources. And then they make a great leap to suggest that this tells us something about human societies 100,000 years ago in Africa!
But perhaps even more irritating to me are the conclusions they draw from their weak, flawed information.

Harrison said she hopes that in addition to helping investigators solve crimes, the results…can help create prevention and treatments programs for violent offenders.

HOW? Please explain how positing an evolutionary basis for why a man bludgeoned someone to death, for instance, rather than suffocating them with a pillow, is at all useful in prevention and treatment. How does it help solve crimes? Everyone is the product of evolution, so this is about as useful as declaring that we have discovered that all people are biological, I hope this helps the police solve some crimes.
In the paper, they say “To augment efforts at understanding and preventing these crimes, future researchers and law enforcement officials may wish to keep this in mind.” Keep what in mind? That sex differences exist? That human behavior is the product of evolution?
They also claim to have “interpreted the data utilizing evolutionary theory”. Shocking news: I know what evolutionary theory looks like, and there is no evolutionary theory anywhere in the paper. The closest they come is to make assumptions that unusual behavior in a single culture in a single century is representative of the deep history of our species, and then declare that their assumptions confirm their perspective on evolution. There is no comparative work. There is no deeper analysis of mechanisms. They are only appropriating the credibility of evolutionary biology as a label to make the work seem more sciencey.
Honestly, evolutionary psychologists: drop the abused term “evolutionary” from your discipline. There’s good and valuable information to be gathered from the study of the psychology and sociology of crime, but it’s going to require a better explanation than “evolution done did it.”

Comments

  1. says

    From what I’ve read, the image of prehistoric men as mighty hunters, bringing down mammoths and whatnot with their crude spears, is way overdone. Men did plenty of gathering, and everyone participated in trapping, which is another thing altogether.
    But hey, who needs data when you have a story that’s just so?

  2. nomdeplume says

    Just when you thought EvoPsych had reached the bottom of the barrel labelled “Really bad science” an even worse study comes out of the woodwork. Did these people not read what they had written and think “yeah, nah, this is total crap”?

  3. Matt G says

    I attended a Learning and the Brain conference last weekend. One of the keynote speakers (Nicholas Christakis – anyone know him?) mentioned evopsych, so I turned on my spidey senses. He really didn’t say anything that made me think “where’s your evidence?” He talked about the “Social Suite,” the traits that make us such good social primates: individual identity, love, friendship, cooperation, preference for the in-group, “mild hierarchy,” and teaching.

  4. hemidactylus says

    I wonder if PZ is cherry picking the bad ones, but there seem to be quite a few bad ones to serve as fodder.

  5. hemidactylus says

    @6- John Morales
    That’s a good question. I’m not sure. Is the field universally bad? He started off as an obnoxious polemicist for EP with a very particular set of skills translatable to his “enlightenment now” thesis, but was Pinker’s language acquisition stuff much better than what PZ highlights above?

    I’m biased against EP and pretty much hold to the Gouldian short circuit of nonaptive spandrels and cooptive exaptation. I’m not much of a devil’s advocate. Sorry.

  6. christoph says

    The FBI’s Behavioral Science Unit did much better and more extensive research on serial killers than the EvoPsych enthusiasts. John Douglas wrote several excellent books on the subject, I’m guessing some of the people frequenting this blog have read them.

  7. lochaber says

    Women tend to like pink, because back when they were hunting, it benefited them to eat the most nutritious organ meats before they spoiled, and men tend to like black and dark blue, because most edible berries are black or blue.

    It’s just Science…

  8. says

    It jumps directly to the idea that the reasons for the differences can be found in evolution.

    No, you can’t really pretend there’s any “evolutionary” explanation for such a grossly aberrant behavior in such a tiny minority of the overall population.

    This is all just an unusually lame attempt to view some human behavior through the cracked and dirty lens of some old, dumb gender stereotypes; and pretend they’re doing “science.”

  9. says

    The data run from the late 19th century to the present. I don’t think there were many hunter-gatherers around ten to become SKs. The could have tried a sociological analysis instead. Over that time there has been a transition from the traditional large family with the husband as the “breadwinner” to the nuclear and post nuclear family with a loss of the extended family, the communal village and more human isolation and increasing female independence and autonomy. The real question they should be asking is does the data show a shift in SK behaviour that correlates with those changes. Things like are female SKs more likely to reach for the AR-15 than the cyanide bottle and vice versa for the male SKs? That would be far more useful to guide policy and prevention. I mean if you can show an increasing trend for women to use AR-15s to go after alpha males, the gun-fondling Republicans might do something about guns even if its only to keep them out of women’s hands.

  10. StevoR says

    @7.hemidactylus : “I’m not much of a devil’s advocate. Sorry.”

    Don’t apologise to us! Apologise to the Devil after all your his advocate yeah? Huh… actually that’s kinda hard since he don’t exist.

    Er, apologies for poor devil’s advocacy to the Pope maybe? Since that’s where the term came from for those saying people aren’t saints..

  11. StevoR says

    PS.

    This is a video about a controversial and unpleasant topic which I fear is going to get demonetized or even blocked by YouTube, so I’m going to preface it by saying I’m going to use a euphemism: it’s about bad people who serially unalive lots of other people, and I’m going to refer to them as SKs. You’re smart people, you can figure it out. You’re smarter than YouTube, anyway.

    Is youtube really that sensitive as to demonetise and punish people for merely saying “Serial Killers” and discussing the topic?

    I can understand why they’d discourage praising or celebrating them but really just using the words and talking about them at all gets negative consequences? Seems Over The Top and too harsh to me.

  12. birgerjohansson says

    I was one of probably several who forwarded this to PZ – I do not know enough about statistics to do nit-picking but for such aberrant behavior it is pretty obvious you need input from mental health professionals rather than speculating about evolutionary causes.

    BTW it is obvious Evil Cat took an interest in the subject of discussion.
    As someone that has received little “gifts” from cats, I understand his interest in serial killers.
    I would respect the author of the article more if it had been about the possibility of virus-transferred genes from felines to humans.

  13. rietpluim says

    Who is the young woman with the glasses and the hippie hair who keeps popping up in right-wing memes? Must be annoying for her.

  14. birgerjohansson says

    My apologies for misgendering the cat.
    Also, if the author likes indirect sources there is a documentary about someone named “Dexter”.

  15. birgerjohansson says

    There are a lot of indirect sources (films) about aliens killing people for fun. I see a big field of evopsych research opening up.

  16. Bruce says

    All hail our genius Evo Psych overlords, who figured this out.
    It MUST be true, because ONLY such SK evolution perfectly explains the clear observation that this evolutionary trend accelerated through the population and dominated it, which is why all humans went extinct 6 million years ago, just like our chimp, bonobo, gorilla, and orangutan ancestors all did before that. In the face of this observation, we can’t argue with science.
    Groan …

  17. outis says

    Ah ha, we could indeed see the Evil Cat Apparition prowling about. Well, ’tis said that they linger around people on screens because they like to keep an eye on their human slaves, particularly when said slaves do strange things. And of course being tsunderes, they demand attention during said tasks, only to spurn it when the human has finished working and can give it. Meow.
    And concerning YT’s famed algorythm: dun worry, it’s an idiot. Artificial intelligence, more like artificial stupidity seeing the frequency at which it bombards me with ads of no interest whatsoever. To the point I am using CDs again when I want some background music, without the Artificial Fool interrupting Scarlatti with NFL ads. Hhhhh.

  18. hemidactylus says

    North American F1 driver Checo wins Azerbaijan GP at about same time the Gulf of Mexico stopped week long target practice on me with supercells producing mesos and hailcores. A great day to be alive and hear the glorious Mexican national anthem as the sun comes out! Take that xenophobic Floridian MAGAts.

    Oh wait, more wind driven rain. Checo’s win fails to quickly stabilize the atmosphere. Shrug.

  19. birgerjohansson says

    Bruce@ 20
    If some specific behaviour trait was similar with a living relative (bobobo?) and was correlated with identifiable genes it would be a valid target for evopsych-NT (without the luggage of bullshit).

    BTW I was raised with limey english – is it always “behavior” in ‘Merican?

  20. hemidactylus says

    In what Freud called narcissism of small differences we have to distinguish ourselves from the Brits via our spelling and our usage of terms like “knock up” and “fanny”. We got Trump and they got his clone Boris which reversed Thatcher preceding Reagan.

    The chips are different here.

  21. birgerjohansson says

    OT
    Traute Lafrenz , the last surviving member of the White Rose resistance group died April 6th.
    She was 103 years old.

  22. birgerjohansson says

    BTW
    Unsupported premises? Unwarranted conclusions? I have the Swedish xenophobe party (aka SD) for that.
    Or the client press of the British Conservative party.
    I will not discuss the German Bild-Zeitung. It would ruin your weekend.

  23. birgerjohansson says

    OT- ish but useful for biology.

    “New method improves accuracy of DNA sequencing 1,000- fold to detect rare genetic mutations”
    https://medicalxpress.com/news/2023-04-method-accuracy-dna-sequencing-fold.html

    I include it because accuracy may help spot the few cases where a single gene is important for behavior as distinct from behaviors entangled with multiple genes.

    There are a few cases where violent offenders have had a mutation running in the family, I suppose this disproves the idea of killers killing for killing’s sake has some evolutionary root.

  24. Pierce R. Butler says

    John Morales @ # 6: … what’s an example of a not-bad one?

    I have several times posted questions about Malcolm Potts and Thomas Hayden’s Sex and War: How Biology Explains Warfare and Terrorism and Offers a Path to a Safer World, hoping to get a good critique of what struck me as intriguing evo-psych (by an MD and a professional writer, neither a psychologist nor an evolutionary biologist).

    Seems to me their thesis, based (to greatly oversimplify) on ideas of why chimps get so much more violent than bonobos, might have some merit, but I so far have found no responses by those better informed, and am posting this by reflex and not in expectation of substantial reply.

  25. Ed Peters says

    The four stages of Evo Psych :
    1. I felt something in my gut.
    2. It moved to my rectum and got stuck.
    3. I pulled it out of my butt.
    4. Evo Psych!

  26. hemidactylus says

    I never thought I ‘d say an Indycar Alabama GP was exciting to watch. Seeing former F1 driver Grosjean fight off another driver Will Power for 2nd in last laps was awesome. NZ’s McLaughlin wins. So many Alabamans watching from the lawn with towels and lawn furniture which is supercool. No over the top glamour as with F1 and far more competitive where Red Bull blows everyone off the track by far in F1.

  27. StevoR says

    @15.John Morales : Ok, thanks.

    @22. hemidactylus : Followed the Baku race last night on youtube. Good win for Perez but pity the car didnt let Piastri do much. They can create quite impressive disturbances in air but sadly just on the very local scale.. Like affecting the car behind. Less so now with the new aerodynamics rules.

  28. chrislawson says

    hemidactylus@5–

    That used to be my position, too, until a few years into the evopsych fad I had been given nothing but crap papers even by the most ardent defenders of evopsych when I asked them for some examples of really important papers. Nada. One defender even sent me a link to the appalling Kanazawa colour-preference study as an example of great EP work. I have never, ever, been shown a good EP paper and it is now so far down the track that I don’t believe any exist or someone, somewhere would have pointed it out.

    I’d now go even further and say that EP as it exists today is literally incapable of producing good work. I don’t say this lightly, but given the number of people who have tried to carve out a niche in EP, and the fact that many of them are pretty smart people, I would have expected a few decent papers by now. They don’t have to be earth-shattering, just solid. Like 99.9% of all published research. And yet even the smart, energetic exponents of EP have failed to produce anything of note even for just being a rigorous study.

    And I think the reason for this is that we simply don’t understand neuroscience well enough to make many interesting testable hypotheses about evolutionary influence on psychology. We can and do study evolution many ways, but at this point in time there is no measurable variable in psychology or neuropsych that can be readily investigated from an evolutionary perspective in the same way that, say, fossil progression or genetic differences in cladistics can. Which means that any hypothesis testing right now has to rely on observations that are either so broad as to have numerous valid interpretations, which EP proponents almost always ignore in favour of assuming the EP hypothesis, or so obvious that we don’t need EP as a discipline to explain it.

    A lot of this work was done well before EP was even a term — for instance r/K selection was first studied back in the 1960s…yet by the 1990s it was known to be an extremely limited theory that failed most empirical testing and is now considered to be an over-simplification that at best holds in a few situations…and yet here we are today with EP proponents using simplistic r/K-like models (or in some cases actual r/K models rather than the empirically more successful alternatives because, hey, why worry about theoretical robustness when you can get yourself quoted uncritically in The Economist?) and digging for vague, sometimes outright incorrect correlations, despite literally decades of evidence that this is never going to be sufficient for any useful explanatory theory.

  29. says

    …Which means that any hypothesis testing right now has to rely on observations that are either so broad as to have numerous valid interpretations, which EP proponents almost always ignore in favour of assuming the EP hypothesis, or so obvious that we don’t need EP as a discipline to explain it.

    Evolutionary Psychology — the new Natural Law Theory!

  30. Dennis K says

    After your video (“EvoPsych and SKs”), I was recommended to watch one on Chinese-made SKS rifles.

  31. birgerjohansson says

    Dennis K @ 36
    We are genetically predisposed to use tilting-bolt semi-automatic rifles?

  32. John Morales says

    No, birgerjohansson.

    The feed was affected.

    (Happens to me too, at times)

  33. unclefrogy says

    …Which means that any hypothesis testing right now has to rely on observations that are either so broad as to have numerous valid interpretations, which EP proponents almost always ignore in favour of assuming the EP hypothesis, or so obvious that we don’t need EP as a discipline to explain it.

    and the conclusions are based on ideas and interpretations of what humans were like in prehistory which are gross assumptions at best from only scant physical artifacts and no cultural evidence at all.
    they should only publish on brown stained paper

  34. Dunc says

    Pierce R. Butler, @ #29:

    I have several times posted questions about Malcolm Potts and Thomas Hayden’s Sex and War: How Biology Explains Warfare and Terrorism and Offers a Path to a Safer World, hoping to get a good critique of what struck me as intriguing evo-psych (by an MD and a professional writer, neither a psychologist nor an evolutionary biologist).

    This review by Paul Rutherford of the University of Toronto looks to be a pretty good critique to me.

    The other observation I’d make is that ideas about the aggressive nature of chimpanzees generally rest on extremely shaky foundations, mostly coming from observations of a single troop whose behaviour was modified by human interaction (specifically feeding the chimpanzees).

  35. Pierce R. Butler says

    Dunc @ # 40 – Thanks for the link: first I’d seen addressing that book from an academic perspective. I don’t think Rutherford gives it due justice – he leaves out some specific points made while accusing the authors of vagueness – but he does provide worthwhile context.

    The Narvaez article in your other link fails to persuade, alas: she whacks away at a book which (according to other reviews I’ve read) certainly has earned a goodly share of whacking, but most just expresses the views of a liberal reformer – not a primatologist (approximately the same critique Rutherford makes of Potts and Hayden).

    Neither of your links points to anything really worthwhile in the field of evo-psych – maybe another generation, using another label, will find a way to pull pearls from that mud.

  36. Dunc says

    The Narvaez article in your other link fails to persuade, alas

    It’s not the best summary right enough, just the first link on the topic that came easily to hand… The whole debate around chimpanzee behaviour is one I’ve seen and occassionally followed for a few years, but unfortunately the search results are so heavily polluted with crap it’s difficult to find a good summary.

  37. Pierce R. Butler says

    Dunc @ # 42: The whole debate around chimpanzee behaviour … the search results are so heavily polluted with crap it’s difficult to find a good summary.

    Lotta that going around these days. I suspect that if somebody set up a search engine with an effective crap filter, it would destroy the internet as we know it.

    Thanks again!