Evolving Diverse Fragility

Over the last 50,000 years humans have evolved many fragile features – features that in the wrong situations fail badly, but in the right situations gain greatly.  Apparently, in previous environments the cost of failure was too high to tolerate such fragile features, but our larger denser societies somehow magnify the gains while minimizing the losses, enough to make such features useful.

I’m not entirely clear how this works, but it does suggest even more diverse fragility in our future, and the importance of supporting such diversity.  Some details:

Most of us have genes that make us as hardy as dandelions: able to take root and survive almost anywhere. A few of us, however, are more like the orchid: fragile and fickle, but capable of blooming spectacularly if given greenhouse care. So holds a provocative new theory of genetics, which asserts that the very genes that give us the most trouble as a species, causing behaviors that are self-destructive and antisocial, also underlie humankind’s phenomenal adaptability and evolutionary success. With a bad environment and poor parenting, orchid children can end up depressed, drug-addicted, or in jail—but with the right environment and good parenting, they can grow up to be society’s most creative, successful, and happy people. …

Researchers have identified a dozen-odd gene variants that can increase a person’s susceptibility to depression, anxiety, attention-deficit hyperactivity disorder, heightened risk-taking, and antisocial, sociopathic, or violent behaviors, and other problems—if, and only if, the person carrying the variant suffers a traumatic or stressful childhood or faces particularly trying experiences later in life.

This vulnerability hypothesis, as we can call it, has already changed our conception of many psychic and behavioral problems. …  Recently, however, an alternate hypothesis has emerged from this one and is turning it inside out. … Yes, this new thinking goes, these bad genes can create dysfunction in unfavorable contexts—but they can also enhance function in favorable contexts. The genetic sensitivities to negative experience that the vulnerability hypothesis has identified, it follows, are just the downside of a bigger phenomenon: a heightened genetic sensitivity to all experience. …

Focus on just the bad-environment results, and you see only vulnerability. Focus on the good-environment results, and you see that the risk alleles usually produce better results than the protective ones. Securely raised 7-year-old boys with the DRD4 risk allele for ADHD, for instance, show fewer symptoms than their securely raised protective-allele peers. Non-abused teenagers with that same risk allele show lower rates of conduct disorder. Non-abused teens with the risky serotonin-transporter allele suffer less depression than do non-abused teens with the protective allele. Other examples abound …

A genetic trait tremendously maladaptive in one situation can prove highly adaptive in another. We needn’t look far to see this in human behavior. To survive and evolve, every society needs some individuals who are more aggressive, restless, stubborn, submissive, social, hyperactive, flexible, solitary, anxious, introspective, vigilant—and even more morose, irritable, or outright violent—than the norm.

All of this helps answer that fundamental evolutionary question about how risk alleles have endured. We have survived not despite these alleles but because of them. And those alleles haven’t merely managed to slip through the selection process; they have been actively selected for. Recent analyses, in fact, suggest that many orchid-gene alleles, including those mentioned in this story, have emerged in humans only during the past 50,000 or so years. Each of these alleles, it seems, arose via chance mutation in one person or a few people, and began rapidly proliferating.

Hat tip to Tyler.

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  • http://causalityrelay.wordpress.com/ Vladimir Nesov

    So holds a provocative new theory of genetics, which asserts that the very genes that give us the most trouble as a species, causing behaviors that are self-destructive and antisocial, also underlie humankind’s phenomenal adaptability and evolutionary success.

    Shouldn’t that be intelligence?

    • Anonymous

      *Caution!* Some of the people who post here are employed in Academia and do not yet have tenure. For them, discussion of any ties between intelligence, genes, and the evolution thereof, is not allowed (except, that is, to assert that no such ties exist). Are we all clear on that? Very good. You may now continue the discussion.

      • http://cob.jmu.edu/rosserjb Barkley Rosser

        Anonymous,

        Actually, the issue here is that lots of people who hang around here are absent-minded, physically weak, socially misfitted dorks who can barely get a girlfriend, much less reproduce themselves. However, ah ha, that they might be geniuses allows them to survive, at least to some extent in some environments that allow them to do their thing and find an equally dorky partner.

      • http://denisbider.blogspot.com/ denis bider

        That seems unfounded for the readership in general, as well as unnecessarily offensive to those for which it might be true.

        With regard to “unfounded”: you have nothing but your own imagination on which to make conclusions about the readership of blogs like this. The fact that, given these few clues, your imagination leads you to such a negative and judgemental vision, indicates that you yourself have bones to chew.

        With regard to “unnecessarily offensive”: even if someone _is_ absent-minded, physically weak, and does not fit in well with a society that treats him like a dork, this doesn’t mean that he’s not actually a genius. He very well might be. The reason such a person can be a social misfit is because such people are rare; they thus tend to be deprived of the company of similarly minded peers when growing up; and thus tend to develop a social personality belatedly.

        All in all, your comment is a fairly ugly ad hominem, with no bearing on the truth of what you were responding to.

        And yes, in my opinion, something like the satirical thought by Anonymous is likely true.

      • Marian Kechlibar

        “absent-minded, physically weak, socially misfitted dorks who can barely get a girlfriend”

        Yay, that sounds like a plurality, if not majority, of software developers. The guys that developed the browser we are using now…

        Really, visit a campus where mathematics and programming are studied, and you will see very strange people. Especially if you visit the rooms, because some of them never go outside. I remember a guy who constantly forgot to eat, and was only kept alive (sitting at the computer, of course) by mercy of his roommate, who would occassionaly bring him some groceries.

  • paretooptimal

    “children can end up depressed, drug-addicted, or in jail—but with the right environment and good parenting, they can grow up to be society’s most creative, successful, and happy people”

    All those low status, unproductive, anti-social people are actually hidden geniuses if only society gave them the chance? Sounds too PC, too convenient to be true. There’s no reason why a person with a “dandelion” trait can’t just revert to the normal pathways if they were born in a unsuitable environment. It wouldn’t be too hard to have a gene that turns these “dandelion” genes off in the event of stress.

    • http://www.existenceiswonderful.com AnneC

      All those low status, unproductive, anti-social people are actually hidden geniuses if only society gave them the chance? Sounds too PC, too convenient to be true.

      Hmm, this seems like a potential bias here. Truth doesn’t care about “PC-ness” at all, in terms of either confirming or denying its directives (for any given cultural/temporal snapshot of “political correctness”, which is a rather capricious concept to begin with.).

    • Psychohistorian

      Truth doesn’t care about PC-ness or equality, but evolution, in a certain sense, does.

      If you’ve got genes controlling something as complex as proclivity for depression, ADHD, etc., it seems very unlikely that they managed to propagate fairly extensively without an upside. Of course, that upside need not be anything we’d call admirable; maximizing descendants isn’t really something society sees as a good terminal value. I suppose it’s possible that depression and ADHD and so on may increase descendants somehow, so the “downside” may be the upside.

      Thus, some skepticism towards PC conclusions is merited, but if there’s a downside, and it has significant prevalence in the population, then it seems there should be an upside, whether society would call it an upside or not.

    • steve

      I think it may be more complicated and uglier then that. It is not clear to me that all Orchids would be benificial to society. They may include a few Geghis Kahns. i.e. Given the right enviornment they are capable of leading an orgy of destruction that also results in spreading their genes far and wide.

  • http://rationalmechanisms.com DWC

    All of this helps answer that fundamental evolutionary question about how risk alleles have endured. We have survived not despite these alleles but because of them. And those alleles haven’t merely managed to slip through the selection process; they have been actively selected for. Recent analyses, in fact, suggest that many orchid-gene alleles, including those mentioned in this story, have emerged in humans only during the past 50,000 or so years. Each of these alleles, it seems, arose via chance mutation in one person or a few people, and began rapidly proliferating

    And then along comes a catastrophic plague killing off a large precentage of the population wiping out most of the dandelions (common traits) leaving all the orchids (uncommon traits) unscathed.

    Yup, I get it now.

  • Nathan

    To survive and evolve, every society needs some individuals who are more aggressive, restless, stubborn, submissive, social, hyperactive, flexible, solitary, anxious, introspective, vigilant—and even more morose, irritable, or outright violent—than the norm.

    ALERT! ALERT! Group selectionism!

    • http://cob.jmu.edu/rosserjb Barkley Rosser

      There is nothing wrong with group selectionism as long as the so-called Hamilton-Price equations are fulfilled, although those equations were actually first identified 20 years earlier in the 1950s by James F. Crow, the last of the old neo-Darwinians, Richard Dawkins to the contrary.

      • Jess Riedel

        I’m a complete amateur when it comes to evolutionary bio, but wouldn’t a society be much too large for realistic group selectionism? I have trouble believing it could extend beyond a small tribe.

      • http://cob.jmu.edu/rosserjb Barkley Rosser

        The equations cover that. Moving up from the gene, the smaller and lower level the “group,” the more likely that it may operate.

  • Dave

    “children can end up depressed, drug-addicted, or in jail—but with the right environment and good parenting, they can grow up to be society’s most creative, successful, and happy people”

    Sure,people like this do reproduce rapidly,leaving government agencies to raise and care for them. But neither the government nor the parents of such children give them the right environment and good parenting.
    If they did we would see hordes of happy creative children running everywhere. Since we aren’t seeing this, what is this other than an “if only we spent more on social welfare” plea?

    • http://www.rationalmechanisms.com richard silliker

      We do not need more social welfare. We must seperate the rational from the surreal by defining our metaphors correctly or not at all. Once this is done we will have a clear picture of what needs to be regulated and that which can be left to its own.

  • http://permut.wordpress.com/ Michael Bishop

    Interesting theory, but what exactly is the evidence at this point? As Nathan points out, there is a particularly casual group-selection argument which makes me worry about this source.

  • Sasha

    Here is a good article that explains this concept for “bipolar” gene: http://www.psycheducation.org/BipolarMechanism/5BigPicture.htm

  • Jackson

    Well, if say Dyslexia wasn’t recognized by scientific studies so much of the damage that has occured could have been avoided by being more caring.
    The majority of human history being blighted by war, disease and scarcity, expediency tended to rule (and still thrives) – a hard habit to break from.

    What about James Clerk Maxwell (‘Daftie’)? The sort of people who ridiculed him were probably rather astute when it came to exploiting the commercial benifits of his powerful forumulations.

    How much of society now is underpinned by these ‘forumulations’ (partially autistic by nature?) and if so, the extent to which that is a problem not being properly addressed because too many addicted to ‘Grand Theft Auto’ type spin-offs?

    As with anything I suppose, trying to get that balance.

    • Psychohistorian

      Um, what?

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  • http://akinokure.blogspot.com agnostic

    Better article on this topic: “In our genes” by Harpending & Cochran, PNAS. (Google; it’s not gated.)

    There’s too much, er, flowery language in that article because it’s in the Atlantic. The basic concept is simple: for some phenotypes (observable traits), there is an interaction between the variant of some gene that you have and the environment. Fragility has nothing to do with it.

    Simple case: imagine you had a genetic variant “predisposing” you to having a hair trigger, always spoiling for a fight, etc. That variant would spread where it paid off, in terms of # of offspring, to be bloodthirsty. In a new environment with large powerful states that restrict violence either to the state itself or to a small ruling coalition of elites, they will round up the hellraisers and kill them off, like they did to the Vikings. So the variant goes extinct.

    The tone of group selectionism can easily be re-cast in individual terms. When societies become more complex, they offer a wider variety of roles for people to fulfill. Before, people with genetic variants that pushed them into unnecessary roles would’ve had fewer kids. With a wider variety of roles, some of those previous deviants may have a niche carved out for them.

    But it’s not true that “every society needs X” — or else every society would have X. Why don’t you find neurotic helicopter mothers in hunter-gatherer groups, while you do among German or Jewish mothers? Must be different selective pressures. Or the German and Jewish ecosystems are more complex and have a wider variety of roles.

  • bgreen

    agnostic. a query on your comment

    “When societies become more complex” i can understand social complexity as part of this but is not diversity the issue?

    society is becoming more homogeneous not less. behavior and culture are tending towards a norm. the evidence of this problem is manifest in political and economic life.

    DWC’s comment “And then along comes a catastrophic plague killing off a large precentage of the population wiping out most of the dandelions (common traits) leaving all the orchids (uncommon traits) unscathed.”….. is to be taken seriously.

  • http://akinokure.blogspot.com agnostic

    “society is becoming more homogeneous not less.”

    Wrong. Certainly over the time period we’re talking about, and heterogeneity has shot up even more since industrialization. There are more niches, and more narrowly defined niches, that have been carved out over time. Going from hunting and gathering to agriculture produced a jump in specialization, and from there to industry even more so.

    “And then along comes a catastrophic plague killing off a large precentage of the population wiping out most of the dandelions (common traits) leaving all the orchids (uncommon traits) unscathed.”

    Doesn’t make sense. Percentages don’t matter for whether a trait will persist — whether the wipe-out is due to a plague, a genetic bottleneck, loss from migration or abduction by aliens. It’s the sheer size that matters. So when the Black Plague or the Thirty Years War wipes out 30-50% of some population, that doesn’t show up as a loss of genetic diversity because millions of people were still left.

    The effects of reduction in population size only show up in cheetahs or something where the sheer population size falls below 100 (or other small number).

    I don’t see what the big point of the plague comment was in the first place, though. A plague will kill off those susceptible to it and leave those who weren’t, or who avoided contact, or who were lucky.

  • Karm Choudhry

    i have always felt that as a species, we have never been able to realize our full potential. Granted that we have made great progression under strong leadership of *some* visionary leaders, but we have never been able to fully cultivate our inter individual diversity.

    I have also always held the opinion that this is through no fault of our own, but through a very faulty system established by our ancestors. The monetary system, which was envisioned to simply keep a tally of resources among members of a society, has now become the sole cause for an overly aggressive and violent world. We have reached a point where several of the alleles, described in the article, are now in an environment so unfriendly to them, that let alone their successful development, it is threatening their very survival.

    The time for orchids to blossom is almost over. It seems like only the dandelions will continue to persist.