Behavioral genetics and the judicial system

Making things better in the long run in not really an objective of the justice system, since the mental universe of those running it has no picture of how that could be done. But it may have happened anyway: over the past few thousand years, unusually violent and uncooperative people have been heavily sat on by the authorities, which had to reduce their evolutionary fitness, at least to some degree.
Hanging does that.

If this was the case, it was due to the fact that criminals aren’t entirely formed by environment: crime is moderately heritable. So if you scrag assholes, gradually the population as a whole slowly changes towards a lower genetic tendency to criminality. You get fewer assholes. Whether this has actually happened in a particular population, and to what extent, would depend on the severity and frequency of state punishment, the length of time this pattern existed, and so on. It may or may not have been significant in a particular population, depending on local history – although there is some reason to believe that something like this may been going on for a very long time (human self-domestication). It’s possible that this trend occasionally reversed.

I have no reason to believe that this was planned. If you look at the trend today, you might get the impression that the powers that be are actively trying to increase the fitness of assholes, but I doubt if that is the case. Sure, that’s the effect, but they don’t know enough to do it on purpose.

For example, when the Supremes decided that being sufficiently stupid is a get-out-of-execution card, they weren’t thinking about long-term biological implications. I doubt if they ever do, or can.

A thought experiment: in the light of behavioral genetics, what should you do when it’s clear that one of a pair of identical twins has committed a truly heinous crime – but you don’t know which one?

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137 Responses to Behavioral genetics and the judicial system

  1. kot says:

    You have to be <70 to escape the death penalty, and then your consolation prize is permanent institutionalization. Hard to get busy in an environment like that.

  2. Unless there’s a lot more identical twins out there than I thought, I would think we can just let this slide. Alternately, if we don’t mind a world in which we punish people for having a 50% likelihood of having committed a crime, why restrict the issue to identical twins? If we’re willing to throw out our traditional conception about “reasonable doubt” for eugenic reasons, why stop at twins?

    • dearieme says:

      Use the Roman Catholic solution: hang ’em both; God will know his own.

    • You don’t seem to get the point of the post. cf “behavioral” and “genetics”

      • Oh, no, I get that, from a strictly genetic standpoint, you’d be best of just killing/sterilizing both twins. But I’m also saying that, if we’re going to throw out the traditional assumptions about justice that thoroughly, we should just as well sterilize/kill all sorts of other people too. Something like maybe 0.7% of people are identical twins.

        It would be a very strange regime that decides, first, that eugenics is so important that we can scrap our traditional notions about justice, but, second, that we should then only apply this scrapping of tradition should stop at lowering judicial standards only for the tiny slice of the population who are identical twins.

        Let’s run a little math. About 1 in 140 people are identical twins, about about 1 in 1400 people (in the US, for this example) will commit a murder — for the sake of argument, let’s say that “murder” is the definition of “truly heinous” (pick your own country and acts if you prefer). So about 1 in 200,000 people will be identical twins who commit a truly heinous deed. If each of these people implicates their innocent (but genetically guilty!) twin, then about 1 in 100,000 people will belong to a twin pair that commits a murder. We solve about 2/3 of murders, so at most 1 in 300,000 people will belong to a twin pair where we know one committed the murder but can’t tell who. Really, the number will be much lower, but let’s be generous to the pro-eugenic side here.

        Now, let’s say a murderer is something like 2.5 standard deviations to the right of the general population on a trait we’ll call “heinousness,” and let’s say the strict-sense heritability of murder is something like .5. Now, I’m a little fuzzy on genetics, but it looks to me like removing every single murderer from the population would move the whole population left-ward on heinousness by about 0.009 standard deviations, thus reducing the proportion of murderers in the next generation from about 7 per 1000 to about 6.827 per 1000. Something like that.

        Now, if you just go after the 1/500 murderers (really less) who are identical twins in unsolved cases where it is known that one is guilty, you’ll probably get something like 1/500 the eugenic result of going after all the murderers. So your payout for throwing out the traditional principles of American justice to go after these twins is likely to reduce the number of heinous people in the next generation only from something like 7.000 per 1000 to something like 6.9997.

        That kind of twin-limited eugenic policy is going to take a long, long, long time before it produces any good noticeable results. I made some assumptions doing the math, and I’m no math expert, so if you don’t like any of them, try it again with your own preferred numbers and see if you get anything substantially different.

      • deuce says:


  3. Jack Gillian says:

    Agree with the sausage – there could well be a utilitarian justification for sterilising the entire families of murderers, for example.

    I suspect this is why the left is so desperate to censor this stuff – given a sensible belief in the heritability of antisocial behavior, a strong focus on communal rights at the expense of the individual, and an anti-natal disposition, and before you know it you’re running a eugenics program. In fact this actually happened in the early 20th century before Hitler made it unfashionable.

    • JayMan says:

      To be fair, facts done automatically demand any policy. Values do that. Justification comes from within.

      Of course, given that, it’s possible certain individuals and groups will automatically react a certain way when exposed to certain facts.

  4. mapman says:

    A cold rational response would be to eliminate both. It’s a numbers game and having almost the same DNA undoubtedly increases the chance of committing another heinous crime. Of course that goes against the whole “beyond a shadow of doubt” concept, which would demand that both let go free.

    Luckily, we no longer have to rely on these prescriptions. Methylation pattern-sensitive DNA tests will be able to exonerate the innocent with very high p. The society just needs to be willing to pay for those tests.

  5. Brendan says:

    The Middle East has surprisingly low crime rates, largely because they harshly eliminate the offenders. But centuries of that hasn’t done much to reduce the violence levels of the Middle Eastern people; in general they are still quite violent and rancorous. So I think the trends discussed in this post mostly apply to the “first world,” where the violent and rancorous tend to be outliers, so that eliminating them does indeed have a positive effect in reducing overall violence in those societies.

    • j says:

      The Middle East is large and it is possible that hides pockets where crime is unknown. Unfortunately, returning tourists report otherwise.

    • Jim says:

      There may be genetic differences in the propensity toward violence against members of one’s own group versus violence against members of other groups. So high levels of violence in fighting between different tribes in the Middle East could be compatible with low rates of violence among people belonging to the same tribe. This was largely how it worked among North American Indian tribes.

      • Greying Wanderer says:

        multi-generational close marriage seems to magnify differences in-group vs out-group behavior imo

        (or alternatively that level of in-group vs out-group behavior is the human default but long term out-breeding over many generations gradually reduces it.)

    • Greying Wanderer says:

      “The Middle East has surprisingly low crime rates, largely because they harshly eliminate the offenders. But centuries of that hasn’t done much to reduce the violence levels of the Middle Eastern people; in general they are still quite violent and rancorous.”

      Clannish populations have exceptionally high crime rates kept in check by social structures designed to manage it e.g. clans living together in compounds protected by lots of armed men and with women and children not allowed out without escort. Hence when they move to the West where those social controls don’t exist they rapidly end up being 70% of the prison population.

      Clannish populations need to maintain high levels of violence genes for protection against the other clans while at the same time not being in a constant state of hot war – the social structure partially squares that circle by keeping the clans segregated and in a permanent state of cold war.

      It’s not just the middle east – the Sicilian mafia came out of a similar setup as do all the less reported modern mafias: Albania, Chechen, Somalia etc.

    • DataExplorer says:

      The most violent members of Middle Eastern societies always had the rewarding outlet of Jihad.

      But the inbreeding may turn out to be a huge factor. It is too politically incorrect to point at the Middle East, but a study of Mormons in Utah revealed that 75-80% of Short Creek are blood relatives of the community’s founder, who had 55 wives. This has led to serious health problems.

      70-80% of North Africans are descended from a single man who lived 2,200 years ago, I suspect King Massinisa of the Punic Wars fame, who had 44 sons. And when tribes that are named Bani-so-and-so (sons of the tribal founder), maybe it’s time we started taking it literally.

      The good news is that both polygamy and cousin marriage are on the decrease in Middle Eastern societies so perhaps this will lead to the gradual rise of rational thinking over Allahu Akbar.

  6. what should you do when it’s clear that one of a pair of identical twins has committed a truly heinous crime – but you don’t know which one?
    I’ve often thought that perhaps there should be some middle ground–similar to exile–for cases where we don’t want to endanger the public nor do we want to harm an innocent person. To some extent, any justice system will occasionally imprison innocents, just because the system is run by imperfect people. We could imprison fewer innocents by raising standards for convictions, shortening sentences, etc., but this would also result in fewer criminals getting imprisoned, putting people at risk. We could put more criminals in prison if we lowered standards, lengthened sentences, etc., but this would mean more innocent people in prison.

    A “nice” prison that isn’t soul-crushingly awful in every way doesn’t sound like a very good way to punish a horrible criminal, but it does sound a little better for any innocent people caught in the net.

    Exile also seems sufficient to solve local genetic problems, and Australia seems none the worse for it.

  7. pyrrhus says:

    As Prof. Greg Clark shows in ‘A Farewell to Alms’, there’s no real question that centuries of executions have reduced violence (and resistance to authority) in the native population in much of the West to very low levels. Unfortunately, as we see in Sweden and the UK, this form of natural selection has also left the natives virtually defenseless against violent foreign invaders and criminally negligent governments…..
    As to the identical twins, obviously you execute both….

    • crimderek says:

      Clark never made that argument about executions and the available evidence suggests that Europeans did not hang or even imprison the vast majority of murderers until about the 17th century. So I don’t think there was any genetic pacification, at least in Northern Europe.

      • Joseph says:

        Clark does make that argument, beginning on page 182, at least in the Kindle version.
        Essentially, his argument is that due to Malthusian conditions, upper class British “values”, including less violence, spread through to the lower classes over many generations. British society selected for those traits that were highly useful in an industrial society.

        • Halvorson says:

          On 182 Clark describes how ancient Rome was a more bloodthirsty society than medieval Europe, which was more bloodthirsty than what we have now. This is standard Steven Pinker stuff. He doesn’t claim that his posited selection was accomplished through execution, which would be unlikely because the great majority of medieval murderers did not hang.

          • gcochran9 says:

            Your impression of medieval crime and punishment is, I think, largely incorrect.

            • Halvorson says:

              This is something from “Society and Homicide in Thirteenth-Century England”:

              “Few of the people who were accused of having taken a human life in thirteenth-century England ever suffered the penalty for their deed that the law required, as can be seen from Table 9. In fact, to kill someone appears to have been a safe thing to do…….

              Only 285 people of 3,492 accused (8.2 percent) were punished for their deed by a court of law. Of these, 38 were clerics who were found guilty, but who, in accordance with the privileges of their order, were released to their ordinary to undergo trial in an ecclesiastical court, where a death penalty could not be imposed. Thus, only 247 people, 7.1 percent of all accused, were executed in accordance with the judgment of a court. When it is realized that a large proportion of all victims of homicide, 531 (21.8 percent), were slain by people all or some of whom the presenting jurors could not identify, it is clear that only a tiny minority of those who killed ever paid the penalty prescribed by law.”

              And this is from Five Centuries of Violence in Finland and the Baltic Area:

              “In only very rare cases was a killer sentenced to death as the law prescribed, and even more rarely was he actually executed. Of 169 cases of homicide in the provinces of Ostrobothnia and Finland Proper between 1540 and 1620, the death penalty is known with certainty to have been carried out in only three or four instances. In all other cases, fines were imposed.

              Was it then that the judges and the lay jurors did not know the law? The Norwegian scholar Hans Eyvind Naess has come the conclusion after finding that in Norway until the 1620s fines were invariably imposed for crimes of homicide, although according to the law they were punishable by death. Naess believes that the judges were ignorant of the law. Is their interpretation valid?

              It is not…..”

              The mystery of why European homicide rates were once very high and then became very low turns out not to be much of a puzzler. When you hang murderers, people stop murdering.

              • Even if the particular murderer was not hanged for his suspected or known crimes, he probably died from an early violent end anyway. Just being an outlaw puts you outside the common run of society and the people you run with are more likely than law abiding Joe the Miller to knife you over a bottle, woman or leg o’ lamb.

              • Joseph says:

                doesn’t seem to deter blacks, oddly.

                In any case, I’m pretty sure most readers of Clark draw the same conclusion as to his argument that I am. It may not be true, but that’s his argument.

              • Jim says:

                So in 13th century England 8% of murderers were punished. In present day Mexico 2% of murders result in conviction. Conviction rates in cities like Baltimore are also pretty low. By comparison the “Wild West” of the American frontier had a high level of law and order.

              • reinertor says:

                So in 13th century England 8% of murderers were punished. In present day Mexico 2% of murders result in conviction.

                Didn’t they hang a number of people for banditry? Probably a lot of the unsolved murders were committed by them. It’s also possible that some of the unsolved murders were also committed by some of those who were hanged for the few solved murders.

                So it’s possible that a higher percentage of murderers were hanged. Though my second point could be relevant to Mexico, too.

      • pyrrhus says:

        Did you actually read the book? Obviously not….

  8. pyrrhus says:

    In Buck vs Bell (1927), Justice Oliver Wendell Holmes did take a crack at eugenics, ruling that a State could sterilize unfit individuals, with the concluding sentence “Three generations of imbeciles are enough”…..

  9. M says:

    I believe it’s in one of Robert Hare’s books that the share of psychopaths in societies seem to be around 1-2% of the population, for a wide range of different societies where this has been investigated. I thought that sounded like pretty good evidence for John Maynard Smith’s concept of “ESS” — evolutionary stable strategies.

    That is, more psychopaths makes it rougher to be a psychopath, because the rest of the population is forced to become less naive and trusting, but when the pendulum swings too far the other way and we get less psychopaths, it again makes it more easy for them to find soft targets and the numbers will increase a little again.

    Back and forth of this over hundreds of thousands of generations, back to way before there were humans around, and the ratio of hawks to doves (as is Dawkins’ analogy in “The Selfish Gene” for the same concept) would stabilize to a rather narrow range.

    For more recent history, ie not evolutionary long timescales, I suppose you can make a larger impact in the numbers by hunting down the hawks more aggressively As was certainly done in medieval Europe, at least.

  10. The Case for the Defense, a short story by Graham Greene, is about this scenario. A man commits a murder but is seen by a witness who later identifies him in court during the trial. However, the murderer’s twin brother stands up in the court room and the lawyer for the defense asks the witness if she can be 100% sure that it was the brother on the stand and not the one in the gallery who committed the murder. Of course she can’t.

    • Wency says:

      In this example (and in Cochran’s) I’d suggest at least charging them both with obstruction of justice, conspiracy, accessory to murder, or some such. Assuming there’s a strong case that at least one brother is a murderer, then the other is guilty of hindering the prosecution (and by extension, may have given his brother cover to commit the murder in the first place).

      So one brother gets the appropriate sentence and one gets off light. Seems much better than both being acquitted, and more consistent with the Western model of crime and punishment than convicting them both of murder.

      • JayMan says:

        So the non-murderer twin committed obstruction of justice by simply being born, you’re saying?

        • Wency says:

          If there’s sufficient evidence to demonstrate that one twin is almost certainly guilty, and the innocent twin is presented with it but refuses to cooperate in the prosecution of his guilty brother, then he is obstructing justice, even if it’s just his blind bias that leaves him oblivious to the facts.

          • reinertor says:

            I agree with you if the twin brother could help solve the case.

            But I guess it isn’t always so. He denies he was there, and the guilty twin denies it, too.

            How can you know which one is guilty without having known it in the first place? What does cooperation mean from the innocent one, when he can only deny his own involvement? After all, he does deny his own involvement, and is pointing his fingers on his own twin brother. The problem is, his guilty brother does the same thing, and you don’t know which one is which.

      • reinertor says:

        The twin brother doesn’t obstruct justice, he insists he’s innocent, and it was the other one who committed the murder.

        The problem is that the guilty one says exactly the same thing.

      • Jim says:

        Under our traditional system of justice neither can be punished in this case. No system of justice can produce perfect results in all cases. Among the imperfections of our system of justice this is probably the least important.

  11. sainchuck says:

    spitbolling: they could be prescribed chillpills preventively for the rest of their days. also they could be nudged via tax legislation to leave the country(tax increase) or be sterilized(massive tax break). this could be applied to all kinds of people. they tried to sterilize some gypsies in the nineties in our country, but they got shamed and fined by the eu real fast. problem is they don’t pay any taxes to begin with.

  12. swampr says:

    How to explain Australia? Its homicide rate is similar to the mother country despite being heavily descended from banished criminals. Were they all just hapless debtors?

    • dearieme says:

      My own private theory is that the magistrates had no single sentencing policy. So, for example, magistrate A thinks there could be be no worse punishment than being separated from friends, family and native land, so he sentences only pretty vile specimens to transportation. Magistrate B, per contra, thinks the best way to save an essentially good young man from the odious effects of the bad company he’s fallen into is to have him transported to Oz.

      My fall-back theory is that the vilest criminals were mostly prevented from breeding by being imprisoned in Van Diemen’s Land or on Norfolk Island. I also have a third theory: the most frighteningly violent criminals were bumped off by the less violent ones, or by the troops, as an elementary policy of self-protection.

      Added to which I doubt claims that Australians are “heavily descended from banished criminals”. I lived there long enough to learn that the Australian attitude to history isn’t markedly more fact-based than, say … oh, the American.

      • Jim says:

        Does anybody actually have data on how much of the Australian population is descended from convicts? Australia was pretty prosperous in the late nineteenth century so wouldn’t it have attracted a lot of British immigrants?

    • NobodyExpectsThe... says:

      No. Hapless debtors, plus paupers that did some type od theft to feed themselves. Thats most of it.

      Murderers and rapist didnt made it out of the gallows to take a ship.

      And there were not very many of those to begin with. Victorian England was more dangerous than Edwardian England on average, but not much more.

      • dearieme says:

        “Hapless debtors, plus paupers that did some type od theft to feed themselves. Thats most of it.” So the same sort of people who emigrated to the US, minus the religious nuts.

        • jaed says:

          … and the Cavaliers, and the Germans, and the….

          • dearieme says:

            and men abandoning their wives and families, and guys one step ahead of the law, and bankrupts, and deserters, and drink-sodden cavaliers, and Germans in the same categories …

        • That describes those who were transported to Virginia. It doesn’t describe New England, the Mid-Atlantic Quaker settlements, or even the Backcountry settlements. I think David Hackett Fischer’s data is considered pretty good on this.

    • JayMan says:

      A) The criminal population banished to Australia wasn’t necessarily all that violent.

      B) Only 20% of today’s Australians are descended from convicts.

      • swampr says:

        I said “heavily” not “mostly” descended. Perhaps convict ancestry was so swamped by later immigration as to be negligible. But first arrivals have a massively outsize effect on a population. Puritans and Quebecois being extreme cases. Surely there are rural backwaters in NSW where much of the ancestry is from early colonists. Are they terrible places? I don’t know.

        Apparently most convicts were petty thieves. Maybe they were good hearted Oliver Twists fighting to survive Dickensian poverty. However I’m not sure a maximalist hereditarian would be optimistic about a lunar colony founded with “nonviolent offenders”.

    • Broseph Walsh says:

      You’re wrong. We are not heavily descended from those convict first settlers. In fact they barely left a trace at all. Of the current population approximately 30% were born overseas and a further 20% with at least one parent born overseas (2nd generation). Of the parents born here just from eyeballing the immigration numbers I’d say most from the pre-federation immigration wave, gold rush.
      Before this wave, population increase was only due to the importation of people. Firstly because of mortality amongst early settlers and second because the colonies had as much as six men for every women. Before the gold rush the government had to pay people to come here. We’re at the arse end of the world, as far away from anything as you can get. So everyone else that came was being punished. Whether that be the convicts or the guards (a posting in Australia was no promotion). Then a large chunk of the descendents that these people did manage to have were killed in WW1. Which is partly why ANZAC day is such a big thing here. The few woman who lived and were born here watched their sons go off and not come back.
      Thoug, come to think of it there are still plenty of their descendents kicking about. Though it didn’t occur at first. The Aborigines. They’re all half cast these days and I’d wager that those convicts living with that gender ratio probably left a hell of a lot of bastard aboriginal children. Which kind of makes me think of Greg’s post on the origins of Indian admixture in the aboriginal population.

      • dearieme says:

        “The few woman who lived and were born here watched their sons go off and not come back.” I doubt it – that’s probably just more homemade Australian myth. Years ago when I lived in Oz I listened to a radio programme that played recordings of interviews with a few old men who had been Anzacs (WWI). Not one of them – not one, which surprised even me – had a recognisably Aussie accent. Every one had an accent from one part or another of provincial England. So it seemed to me probable that a lot of the Anzac troops came from families who were pretty recent immigrants.

        When I discussed the programme at work the next day not one of my Aussie colleagues had noticed the accents – presumably they knew that these chaps must have been fair dinkum Aussies and had just screened out the contrary evidence.

        • crew says:

          Strange. My grandfather was one of those ANZAACs, and while his ancestors were from Wales (his father, perhaps, but perhaps earlier ancestors) he was born in Australia.

          One can get a good sense of this looking at the RSL records in country towns all around Australia and there are still WWI monuments in places around Australia with the names of those who went to WWI and the impression I get is they were largely born in and around those town.

        • Broseph Walsh says:

          That fits into what i was saying. Already most of the population was from the recent wave of immigration. Of the ones who could trace their heritage back to those original convicts a fair chunk of them died. But you’d still expect the majority of the ANZACs to have been pretty recent English stock. As much of the population was.

    • MawBTS says:

      Not too many Australians come from convicts. Prisoners don’t reproduce much, in general.

      That said, we can claim some fascinating criminals.

      Like Ikey Solomon. A Jewish man who led a gang of child pickpockets. It’s believed that Charles Dickens used him as the basis for a very famous character in Oliver Twist.

      Or Mark “Chopper” Read, a gangland killer who may have committed up to 19 murders. While in prison, he sliced off his own ears so he’d be moved to a different section, away from the attentions of an enemy gang. He also published a children’s book called Hooky the Cripple.

      Or the notorious Shark Arm Murders in the 1930s.

    • Frau Katze says:

      Around the time of the French Revolution the UK got very strict with criminals. Death penalty used liberally. They were trying the violence of the French Revolution from spreading.

      So it seems likely that the ones sent to Australia weren’t really serious criminals.

      • Douglas Knight says:

        Do you have a source for that?

        It sounds backwards to me. Hanging was popular in the 1780s because transportation to America was off the table. Transportation to Australia only began at the time of the French Revolution, but it was much more expensive than transportation to America had been, so it only slowly ramped up and the death penalty slowed down. I think in 1820 the rate of transportation to Australia reached the previous level of transportation to America.

    • Greying Wanderer says:

      IIRC transportation wasn’t used for murder – also many more men than women so reproductive chances much less than the free colonists.

    • ziel says:

      Haven’t any of you people sang “Fields of Athenry” while swinging (and swigging) a pint?

  13. Citizen A says:

    So, think about the underlying settlement patterns of the US- e.g. Albion’s seed- and then look at this:
    The connections are pretty easy to see. Now, blood guilt is not necessarily a good idea- after all, one might just have a murder that would be as a result of a bit of madness. On the other hand, the Las Vegas sociopath seems to be the son of another mass murderer sociopath.

    One or the past occupations for the most violent seems to have been law enforcement- because state sanctioned violence avoided Tyburn’s Tree. The comments about the troops also means they were literally purging the home society of the bottom:

    Nothing is more actively eugenic than putting people on a ship to Jamaica and an early grave. The Dutch did send generations of the better sort to the Indies and early graves as well while running their VOC.

    One should remember that history is populated by the survivors- and now there are more Scots and Irish descendants in Britain and America than in Scotland and Ireland. One might even argue they benefited the most from Empire beyond the upper classes since they spread across the globe as a result.

  14. jb says:

    I’m not sure how the two people being identical twins makes any difference. There could be circumstances where you know that a crime was committed by one of two unrelated people, but you don’t know which one. How is the twin situation different? Also, while heredity probably does play a role in criminality, circumstances also contribute. You have no way of knowing whether the twins are identical genetic assholes, or whether they are in fact fine genetic specimens, one of whom just happened to fall in with a bad crowd (or, equivalently, one of whom was lucky enough to fall in with a good crowd).

    That said, there an interesting science fiction series involving a parallel Earth populated by Neanderthals that Razib Khan has blogged about occasionally. I haven’t read it, but I get the sense that as with much science fiction, the author has made his own preferences known through his work:

    Any serious crime has a single punishment: the castration of the offender and all others who share at least half his genes (parents, siblings, and children). This eugenic practice serves to keep any undesirable elements out of the gene pool without severely punishing an offender, beyond his loss of genetic heritage.

  15. The Z Blog says:

    On the self-domestication question, it seems obvious. If tomorrow were decide that gingers were innately evil and executed everyone with red hair and freckles, it would not take long to remove the ginger gene from the population. Killing those with poor impulse control would eventually reduce that trait in the population.

    The trouble is, when was it ever acceptable to commit murder? The Romans were willing to execute people for a wide range of crimes. Was their levels of execution lower than the Brits? It seems unlikely. For that matter, were the Brits more accepting of murder during the Heptarchy? It does not appear so.

    Population density may provide the answer. Higher population density means a greater ability to police and a greater need to police, for anti-social behavior. Perhaps once human population numbers reach a certain density, the ability and willingness to cull the herd has a cost-benefit ration that does not exist when population density is lower.

    • reinertor says:

      I think the early church had a strange policy: all churches and chapels served as sanctuaries for sinners, priests were even feeding murderers who went there. They wouldn’t let the authorities enter with drawn weapons, or use violence in the house of God, so the authorities had to wait outside. But since the criminal had time (he was being fed by the stupid priests), there was little point in waiting too long, so eventually they left, and so did the criminal, to commit another crime.

      It’s very likely that the Romans totally domesticated the population (which is why nobody wanted to join the legions by late antiquity, and they had to use Barbarians), but then after the fall of Rome it reversed quite a bit, to a large extent probably as a result of such stupid church policies. (Barbarians moving in as a new elite also had something to do with it, probably.)

      Or maybe those policies weren’t so stupid. I’m sure medieval people would have none of the feminist or multiculturalist nonsense. Maybe we’d really need to increase some violent genes in our populations, before more violent populations replace all of our genes, whether causing nonviolence or anything else.

      • Ian says:

        To claim sanctuary, the asylum seeker was required to surrender his weapons. He then had forty days either to surrender to the secular authorities and stand trial or to confess his guilt and abjure the realm (done with a public ceremony) under pain of death if he tried to return. Abjuring the realm also required him to forfeit all his possessions.

        The tradition derives from Greek and Roman times prior to the Christian era.

    • “The Romans were willing to execute people for a wide range of crimes.”

      Source? Not trying to be flippant; i’ve been curious about the executive/punishment aspect of the Roman legal/judicial system for a while. I’m vaguely under the impression that the colleges dealt with local crime and the upper bodies dealt with the political (and maybe the patrician) classes. But i’d love to find a “history of the roman justice system for dummies” reference. Or Gibbon or Mommson, if they are good on it.

    • Halvorson says:

      It was relatively acceptable to commit murder in the old Germanic parts of Europe where the weregeld system held sway. Until the 17th century it was very rare for homicide to be punished with the death penalty. More often, the family of the victim would grant the murderer his life in exchange for all his property. They held the legal right to demand his execution, but with few exceptions chose to take his stuff instead. This situation continued for many decades even after Reformation kings mandated the death penalty in official proclamations. Local courts just ignored them and kept doing things the medieval way.

      I don’t think there ever was any natural selection against criminality in North Europeans, but we do okay anyways.

    • Greying Wanderer says:

      “The trouble is, when was it ever acceptable to commit murder?”

      the other side of the equation is the ability to punish – particularly those who run outside a particular jurisdiction.

      so say the propensity was high and ability to punish low and then Rome comes along and increases the ability to punish and so the propensity goes down until Rome collapses and the ability to punish goes down and propensity goes back up until the early modern urbanization increased ability to punish again etc.

  16. Anonymous says:

    For a truly heinous crime, like the LV shooting, I would choose to execute both.

  17. MawBTS says:

    All of you guys who are saying “hang both the twins” should be careful, methinks.

    Suppose one twin commits a murder, while the other doesn’t. If they share a similar genetic impulse to violence, then clearly the second twin is repressing his impulse through Shaolin monk-like force of will.

    But if he knows he’ll be punished regardless, then why should he even bother controlling his impulse? You’ll have two murderers to deal with, instead of one.

    I propose killing one at random. Toss a coin, maybe. There’s a 50% chance you’ll eliminate the murderer. And if you don’t, and he kills again, you’re still not any worse off.

  18. RCB says:

    “in the light of behavioral genetics, what should you do when it’s clear that one of a pair of identical twins has committed a truly heinous crime – but you don’t know which one?”
    Ei incumbit probatio qui dicit, non qui negat

  19. RCB says:

    Another thought:
    We like the idea of executing/sterilizing a single criminal, because his committing a crime makes him more likely to have a breeding value that tends toward crime. The strength of the association depends on the heritability of criminality, which I’m sure is at least moderately strong.
    But in the twin case, we have two sample points of equal weight: one criminal, one not. The fact that the criminal has a law-abiding twin brother (as far as we know) therefore actually improves our estimate of his breeding value: specifically, it brings down the crimy-ness of the estimate.
    So one could argue that the existence of the law-abiding twin means that we don’t punish even the law-breaker as harshly as we would a normal (non-twin) law-breaker.
    (More generally, relatives should be looked at.

  20. gwood says:

    Execute one twin at random. Subject the other twin to electro-shocks until his memory is gone. Release him. Call it the Schrödinger’s cat punishment.
    Related, Charles Manson supposedly has about a dozen children.

  21. Frau Katze says:

    Crime rates are very low in Japan. But this doesn’t seem to be connected to modern policing.

    I read a book about the Aum Shinriyko cult. The police ignored them for as long as possible. Neighbours of the cult were complaining about them but the police seemed to be afraid of them.

    They killed several people before they used sarin gas on a Tokyo subway. Efforts to solve those murders seemed very weak compared how police in the West act. The relatives of the victims kept complaining but nothing was done.

    It seems Aum Shinriyko were very anomalous. There is organized crime in Japan, but not like this cult. Apparently organized crime is also ignored.

    Something in their distant past seems to have elimated the casual criminal, leaving a police force who just ignored Aum Shinriyko.

    Yet the Japanese were pretty violent in WW II.

  22. swampr says:

    “Muslim killed Muslim for the slightest reason: a cow, a goat, a piece of land or a woman… Two men would argue as the fqih would wake the village by the call to the dawn prayer. And by the sunset prayer, all the men in the village would be shooting at each other.”

    This is how one man recalled hyperviolent Moroccan village life in the 19th century. Old men were suspected of being cowards simply for surviving so long. Moroccan descended people are notably overrepresented in French prisons today.

    And yet… the current homicide rate for Morocco is less than Sweden! Only one criminal execution in the past 30 years. What is the hereditarian explanation for this? Why do Afro-carribeans in the Virgin Islands murder at 20x the rate of Afro-caribbeans in Montseratt?

  23. Greying Wanderer says:

    innocent until proven guilty takes precedence imo – the twin identification case should allow exceptions to standard practice in investigation e.g. lie detectors, get them drunk etc.

    the thing is “bad” genes aren’t necessarily bad – in combination with others they might be good so if the innocent twin marries a pastor’s daughter their kids might be fine.

  24. Joel says:

    Answer: it doesn’t matter whether you know which twin did it or not. The act of the one twin proves that under the right circumstances, the other would commit the same crime. It’s only a matter of circumstance that one is “innocent” while the other is not.

    Therefore, in an ideal society, both should be punished.

    In a more realistic society, however, you should only punish the evil twin.

  25. Bob says:

    There was the “Bloody Code” in England in the 18th and early 19th centuries whereby minor offenses like shoplifting were punishable by death. Mary Jones was a destitute teenage mother whose husband had been pressed into the Royal Navy. She was hanged for shoplifting some coarse linen:

    One can well understand why the law in this period in history is now referred to as the Bloody Code. Of the two hundred and ninety four people executed at Tyburn in the decade from 1765 to 1774 only twenty five were to die for murder and three for rape. The rest mostly suffered for various types of property related crime, such as highway robbery, burglary, housebreaking and forgery.

    It seems amazing today that a young mother should be hanged for what would now considered to be a minor crime, yet in 1771 nobody would have thought anything of it — it was a regular and perfectly normal event. If it was Mary’s first offence, as she claimed, she would probably get a community service order now, especially as he had dependant children. However Georgian justice was being applied increasingly severely at this time. Sixty-two men and six women received the death sentence during this year, of whom thirty four of the men and one of the women, Frances Allen, were to share Mary’s fate. Frances Allen was hanged on Wednesday the 7th of August for housebreaking.

  26. Smithie says:

    Somewhat rarely, there are very significant mental differences between identical twins. So if you are offing both twins, to be a fair heriditarian , I think you would also have to peruse the parents’ and siblings’ records, just to sort out the evil twins from the good.

    • MawBTS says:

      Bilaterally amputate the lower bodies of their parents and siblings. And cut a single leg from their grandparents and uncles. And cut a tibia from their cousins. And so forth.

  27. Difference Maker says:

    Imprison both until a confession

    • Difference Maker says:

      Now, what would constitute a heinous crime?

      One that carried the death penalty. But not just any death penalty culpable crime; it would be for something beyond generally considered conventional, if violent, disagreements.
      Some kind of psychopathic cold serial killing; not just brash thuggery or assassination.

      Therein lies every possibility that the innocent, if freed, might one day partake; and in revenge for their fallen sibling.

      That cannot be allowed. Therefore, both must die

      • Difference Maker says:

        Then there are the ever present issues of the slippery slope, wiping out clans because of genetic relations, etc

        Death from duels may just be boys being boys; treason may be pure rivalry rather than, say, the most faithless treachery; and therefore these may not be intrinsically despicable. Liquidating whole clans pour encourager les autres will tend to remove brave and bold elements from the population, weakening them – and that may be the intent.

        But there is the question of where the setpoint of domesticity attained should be. We cannot have brave warriors if they have never been born. Such a society will fall

        In this case the corporal and other punishments of family members brainstormed in this thread would be more appropriate. In the genetically aberrant case though (the lawyers will have a field day), of the sadistic psychopath where the twin is the same, the death penalty must be applied to both.

  28. Difference Maker says:

    Stone cold autists. I thought I was cold
    Those who are glib should note that any society that becomes too effeminate will simply be taken over by more masculine outsiders.
    One must be careful and not forget that overzealotry in eliminating the bold will mean that there will be no one left to defend the homeland.
    Of course, we will eliminate pedophiles

  29. sinij says:

    Even modern societies need violent men. Who is going to wage war if soldiers going to refuse to shoot and/or quickly develop PTSD?

    • gcochran9 says:

      I can think of people that might describe: people like Paddy Mayne, perhaps. But in general, it is possible to find whole countries that produce excellent soldiers and are at the same time internally very peaceful and orderly.

      As for PTSD, funny how there used to be high-intensity wars where it wasn’t much of a problem.

      • MawBTS says:

        I remember reading about a French knight at Agincourt (or Crecy? I can’t find a link) who after being in the midst of massed longbow fire was terrified by flocks of birds flying over his head. I think he would have received a diagnosis of PTSD in modern times.

        I think it’s always been around, just nobody cared. The notion that every soldier’s life is precious is a modern one.

      • Greying Wanderer says:

        “As for PTSD, funny how there used to be high-intensity wars where it wasn’t much of a problem.”

        Apparently non-military people can get PTSD from concussions.

        Maybe it’s concussion from HE?

        • Greying Wanderer says:

          another time i could imagine a lot of military concussions is hits to the head while wearing armor heavy enough to survive the blow but that would requite specific circumstances whereas HE can effect in a wide area.

          makes me wonder if different helmet types have different concussion protective effects and/or different grenade types have different effects.

      • valiance says:

        But in general, it is possible to find whole countries that produce excellent soldiers and are at the same time internally very peaceful and orderly.

        I was going to immediately suggest the Japanese and the Germans but realized I was probably cribbing that from something the War Nerd said a while back:

        One interesting thing about Colombian killing is they do it both ways: solo and in groups. There are some countries that turn into psycho killers once they put on a uniform, but wouldn’t even run a yellow light once they’re in civvies again. Two classic examples: the Japanese and Germans. The Japanese did things in China that just don’t bear thinkin’ about…beheading contests, sword practice on pregnant Chinese prisoners, baby-bayoneting volleyball — but those same soldiers went home and turned into shy little salary-men who wouldn’t jaywalk, never mind hurt anybody. Same with the Germans: let’em loose in a gray helmet and they think up stuff that’d make Saddam ashamed — but back home in Dusseldorf they’d die before they’d drop a popsicle stick on the sidewalk.

        Then there are the countries that kill real good in private life but won’t fight in uniform — Italians, say. Mean fuckers on the street, in the alley, but put one in a uniform and he can’t wait to throw away his rifle and find a nice cozy cellar to hide out in.

        Colombians are a coach’s dream: the switch-hitters of killing. They kill in uniform or out, home or away, on the street or the battlefield. Equal Opportunity Slaughter: men, women, children, dogs — if it moves, they’ll kill it. For any reason. For no reason. For money, for fun, for the Revolution, for the Counter-Revolution, for practice.

  30. Dave R says:


    Serious question, though. How would we go about selecting against criminality, while maintaining a healthy predisposition towards self-defense and physical courage? It seems like limiting truncation to criminals should work, but on the evidence of modern societies rolling over I’m not sure it did.

  31. another fred says:

    Richard Wrangham proposes that what is being selected out (maybe) is reactivity, i.e. lower self control.

    This is somewhat congruent with the studies of the “warrior gene” and the “super warrior gene” (the 2-repeat of the DRD4).

    • Greying Wanderer says:

      yeah, if impulsiveness is A and capacity for violence is B then most of the time you wouldn’t need to worry about
      – people who were just A (except when they’re driving)
      – people who were just B (unless you really provoke them)
      so maybe historically it was mostly the people who were A+B who got the chop?

  32. j says:

    “What should you do when it’s clear that one of a pair of identical twins has committed a truly heinous crime – but you don’t know which one? “

    If both are hanged, one man will die innocent, and no judicial system can do that. The standard Middle Ages solution was trial by ordeal, by which the accused was subject to fire or water (thrown into the Thames in a sack). If he survived, it was clear to all that he was innocent, if sunk, well, he deserved it. The ordeal had more deterrent effect than hanging and provided more public entertainment.

    As for me, I am against the bloody solutions (murder, castration) proposed by hundred commenters above, and for trial by combat, the judicium Dei. Exciting spectacle and just too, because it is known that God always saves the innocent.

  33. DataExplorer says:

    Alexandre Bissonnette, the perpetrator of the Quebec City Mosque shooting, which killed 6 and injured 19, has an identical twin. As of the time of writing he has not committed any mass shootings. In fact he has done nothing whatsoever to get him in news headlines, despite the fact that the two twins lived together and were known to only hang out together and with no one else.

  34. Warren Notes says:

    If the method of behavioral genetics used to estimate the likelihood that the twin will commit the same criminal act has advanced to the point that we can predict with an accuracy that surpasses legal doubt – say, equal to identifying paternity with a DNA test – I think we would be at least justified in fitting the twin with an ankle bracelet. But – it would require a legal paradigm shift. The courts seem to have avoided blocking anticipated crime due to Constitutional rights and lack of court-sanctioned evidence.

  35. crew says:

    What should the punishment be for the people working on this?
    Would it lead to many more hungry mouths in Africa and other downstream effects?

  36. Philip Neal says:

    I am surprised that nobody has yet mentioned the Swedish twins who were sentenced to a life term of coffee-drinking and a life term of tea-drinking. Wikipedia is sketchy: does anyone know the full story?

  37. snek2020 says:

    Sterilize both, and give them different tattoos so that they can be distinguished from each other next time.

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