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: