Genes can be criminogenic

By Razib Khan | June 26, 2012 11:40 pm

As a follow-up to my post below, I just wanted to check some recent literature on crime and heritability. I found this, Heritability, Assortative Mating and Gender Differences in Violent Crime: Results from a Total Population Sample Using Twin, Adoption, and Sibling Models:

Research addressing genetic and environmental determinants to antisocial behaviour suggests substantial variability across studies. Likewise, evidence for etiologic gender differences is mixed, and estimates might be biased due to assortative mating. We used longitudinal Swedish total population registers to estimate the heritability of objectively measured violent offending (convictions) in classic twin (N = 36,877 pairs), adoptee-parent (N = 5,068 pairs), adoptee-sibling (N = 10,610 pairs), and sibling designs (N = 1,521,066 pairs). Type and degree of assortative mating were calculated from comparisons between spouses of siblings and half-siblings, and across consecutive spouses. Heritability estimates for the liability of violent offending agreed with previously reported heritability for self-reported antisocial behaviour. While the sibling model yielded estimates similar to the twin model (A ≈ 55%, C ≈ 13%), adoptee-models appeared to underestimate familial effects (A ≈ 20–30%, C ≈ 0%). Assortative mating was moderate to strong (r spouse = 0.4), appeared to result from both phenotypic assortment and social homogamy, but had only minor effect on variance components. Finally, we found significant gender differences in the etiology of violent crime

A = additive genetic variance component
C = shared family environment

This table from the paper shows the influence of study design….


All of these statistics are summaries or representations of patterns in the real world. They are not concrete entities in and of themselves. So, for example, the authors admit that their power to detect patterns among females was low. Why? There were simply too few female violent criminals! Second, they speculate that their lower values for adopted-parent comparison had to do with a similar problem: this Swedish sample tended to have adopted parents who were extremely lacking in criminality, while their childs’ biological parents tended toward violent crime.

As outlined in the post below by commenters the biggest issue here is that direct parental suasion and modeling matters a lot less than the broader milieu which the parents raise their offspring in. In a broad stylize fashion Dan Quayle may have been right, but Hillary Clinton was right too: it takes a village.

CATEGORIZED UNDER: Behavior Genetics
MORE ABOUT: Behavior Genetics
  • Justin Giancola

    Likely ancient people would have raised children with the assistance of their relatives or close friends and/or group to some degree, and it would be unlikely for a nuclear family to be as isolated as today. This speaks of said milieu. We may actually seek out more than just major input from two (male & female role model).

  • Dwight E. Howell

    Nuclear family? I’ve worked with students who could not name their grandparents. I’ve worked with students with one mother and many last names. I’ve listened to women talk about always telling the boy friend the kid looked like him until the couple broke up…

    The media has recently published a few articles about guys who make minimum wage with 20 to 30 kids by a large number of different women. This trend was most common in the African American community but rather than them becoming more reasonable and prudent the other ethnic groups are becoming less so but natural selection favors those who reproduce…

    It looks like white liberals with their belief in one kid or no kids are going to go the way of the dodo one way or the other. Just give it some time. Failing to reproduce is going to render any group extinct.

  • JR

    In urban areas, where “the village” (arguably) impresses itself on the lives of individuals with more intensity and at a greater magnitude than in suburban or rural areas, I’d spectulate that the effect of genes to determine behavioral outcomes is trumped greatly by the socio-economics of “the village,” which I would also speculate, would be tempered, to an extent, by family.

    Also, I read a study years ago that found a positive correlation between violent crime and socio-economic disparity between the richest and poorest within a geographic area.

  • JR

    Isn’t it possible that a specific combination of genes that, hypothetically, subdued violent behavior when exposed to one set of environmental factors, could foster violent behavior in another?

  • Grey

    There’s another side to the environment angle which is that a violent person can display differently in different environments

    For the sake of example say the critical traits are
    - violent or non-violent
    - impulsive or controlled
    - good or bad

    where
    good is defined: won’t use or threaten violence unless provoked
    bad is defined: will use or threaten violence to get what they want on a cost-benefit basis

    with eight possible combinations then ignoring the combinations that include “non-violent” or “good” and assuming the combinations containing “impulsive” behave the same in all environments you’re left with one type

    violent / controlled / bad

    Someone like this in a very non-violent environment i.e. an environment with very few people like him in it, doesn’t have to be violent to generate a usable amount of fear. He can get what he wants using intimidation and hints of violence and therefore fly below the radar of any serious law enforcement.

    The same man in a violent environment e.g. prison, might need to kill someone to generate a similarly usable amount of fear.

    Similarly, because (imo) non-violent environments are ones where the rule of law has been strictly applied over time hence reducing the number of violent individuals in the population then they would by definition be environments where violent behaviour has serious sanctions so for a violent / controlled / bad individual in that environment it pays to stealth.

    In a violent environment however the opposite is true. In a violent environment i.e. one where there are a lot of violent individuals, it pays to advertize how dangerous you are.

    So for instance the same individual in a non-violent environment might be a very careful serial rapist and in a violent environment a fairly brazen gang rapist. Being “bad” in a good environment is bad. Being “bad” in a bad environment is good.

    TL;DR
    The son of a violent individual adopted by people into a very non-violent environment might also be violent but the level of violence needed to intimidate the other teenagers in that environment might be (and generally is) below the level that registers as crime.

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Gene Expression

This blog is about evolution, genetics, genomics and their interstices. Please beware that comments are aggressively moderated. Uncivil or churlish comments will likely get you banned immediately, so make any contribution count!

About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com

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