A Revolution in Nature VS Nurture, Part One

It has come to be understood that without some form of Nurture there can be no Nature; that an organism’s genetic coding develops in interaction with the environment, and there is no “normal” or neutral environment. Eliminate the environment and you have eliminated the organism. Of course, all living things have both influences, and they are deeply enmeshed.

With this in mind, I would like to re-visit the seemingly astounding things unearthed in the many twin studies, separated twins, adopted out to different families, and tested later in life for personality traits etc. In short – very short, I admit – these studies famously showed that twins are twins, especially monozygotic twins, even when raised apart in separate families, separate towns, separate states, even sometimes in separate countries, many shared traits to an impressive degree.

(Some, and not a small number of people, have used the apparent triumph of the Nature over Nurture argument that the twin studies seemed to assure to justify some unpopular ideas of social Darwinism and the like. Personally, I too thought the results of these studies appeared to hurt the cause of those people invested in the Nurture side, myself included – although for me it’s a hobby, a train of thought, and not my livelihood. I confess to have been searching for a way out of that disillusionment, mostly from an intuitive thing, a sense that if Nature and our genes rule all, then there seems no point to life, to thought, to the choices we make. Life in that world seems mechanical and rather pointless. But a new – at least to me – insight seems to have the power to save my hurt feelings in the matter. I hope to provide some reason and logic; I hope I am doing more than asking that anyone simply share my feelings about it.)

In terms of evolution, it would be basic to say that over the long term, environment, and living things’ responses to it, have shaped our genetic makeup, and for a few decades now, genetic science is showing that this is also true in the short term, that during the development of a single organism, environment is in interaction with genes, activating and making dormant different genes. In other words, it seems that it takes a creature’s genes and the creature’s environment to produce an adult, developed creature of a particular, identifiable phenotype. I’m sure I’m not saying anything intelligible there, but the point is simply this, that it takes both, genetics and environment to produce a creature that would seem to be within the parameters of what we might require to identify it. Too much genetic variance, it’s a different sort of creature, a different species. That we all know, but considering the interaction of genes and environment, we can also very possibly assert that if the environment were not also similar enough during the creature’s development, a different creature may also emerge, a different phenotype.

Now if that were true – and I have a blogger or two to run this past, people who know better and will no doubt try to correct me in ways I may still not understand – if that were true, then what might that mean about the twin studies?

It might mean that the genes these people share are not the only thing they share. It could very well mean that different families, in different towns, different states, even sometimes in different countries are actually similar enough environments to produce such strikingly similar phenotypes.

It could very well mean that the assumption of those who would interpret the results of the twin studies to support unpopular things like social Darwinism (and worse), the assumption that these separated twins were actually raised in meaningfully different environments – is false.

Here’s Part Two:



5 thoughts on “A Revolution in Nature VS Nurture, Part One

  1. Patrick Clarkin June 19, 2014 / 1:26 pm

    Hi Jeff, I wouldn’t worry too much about genes ruling all, or the idea that if they are in control that there is no point to life. Without genes, we wouldn’t be here, so we have a lot to thank them for. The whole idea of free will is another hornet’s nest, but to some degree we have choice on how to use the time we have here. Steven Pinker once said, half-jokingly, about his own choice to not have kids: “By Darwinian standards I am a horrible mistake…But I am happy to be voluntarily childless, ignoring the solemn imperative to spread my genes. And if my genes don’t like it, they can go jump in the lake.” So genes don’t rule all. 🙂

    Anyway, on the twin studies, I’d have to see the specific studies. I don’t doubt that genes should be involved in personality traits and behavior, or that twins could be more correlated for certain traits than other related people. But it’s not a straight one-to-one correlation, and it doesn’t mean that genes ‘triumph.’ It just means they are heavily involved in the equation. But, while identical twins are a pretty neat way to ‘control for’ genes, there really is no equivalent way to standardize the totality of ‘the environment.’ How different are environments? Suburban Seattle vs. suburban St. Louis? Residing in the home of a tycoon in Dubai versus with a hunter-gatherer band in Botswana? (That’s just an example, but you get the gist). Anyway, just some thoughts.


    • neighsayer June 19, 2014 / 1:50 pm

      ADR, but you’re no help at all!
      I think I’m not making myself understood, all those N VS N thoughts are in the past for me now too, already.
      I’ll stick with my counter-intuitive strategy of deciding I’m right though, in lieu of any real argument from folks like yourself.

      I imagine you know where I’m going with it. If I don’t get a real objection from Ad Nausica or my daughter (studying bio-chem and genetics in university), I’ll post Part #2 soon and you’ll see what this is about for me . . .

      Thanks for nuthin’!



      • Patrick Clarkin June 19, 2014 / 2:04 pm

        Hmm. Maybe we’re talking past each other. It would probably be easier to do this in person, but I think that wouldn’t be possible. I live in New England 🙂 In the meantime, I’ll wait for Part 2, and see if I can do better.


        • neighsayer June 19, 2014 / 2:31 pm

          Yes, the entire continent is between us. I’m fairly OK with where I’m at about this. The key concept is “meaningfully different environment.” You’ll see. I’m writing it now.

          Thanks, Patrick, it’s all good.


        • neighsayer June 19, 2014 / 8:20 pm

          OK, part two’s up, and the link’s in the bottom of this post now . . .


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