Blueprint: How DNA Makes Us Who We Are I

Robert Plomin, the behavioral geneticist, has written this book to sum up several decades of his research for general readers. So far, I've only read the initial chapters, which describe research on the characteristics of adopted children compared to their natural and adopting parents and unrelated siblings over time, and research on the characteristics of twins who were adopted into different families. The gold standard for this kind of research is identical twins who have been adopted into different families. Unfortunately, only a few such twins have been studied, and even though those studied indicate a very high correlation between characteristics of identical twins who have been raised apart, the number of identical (monozygotic) twins is too small to produce statistically significant results. The general findings indicate a relatively high correlation between the characteristics of closely related people, suggesting that environmental factors are far less important than genetic relatedness in producing characteristics in people.

Although adoption itself is not a subject that excites me much, I have often wondered whether parents who adopt know what they're getting into. I don't think so. Of the few instances with which I have some familiarity, the results have tended to be disastrous. This was because, as Plomin says, adopted children don't usually have much in common with the families into which they are adopted, and adopting babies, who haven't developed their adult personalities, doesn't improve the odds. Plomin correctly notes that nature significantly outweighs nurture in these situations.

So far in the book Plomin has not used the kind of language that I use to think about the issues associated with heritability, but it doesn't look as if we are going to have disagreements. For me, this goes way back to my adolescence, when I began to think about determinism. That had more to do with physics and Einstein's famous statement, "God does not play dice with the universe." For many years I hemmed and hawed over whether truly random events occur and even whether paranormal phenomena are real; my current thinking is that we do in fact live in a deterministic universe without true randomness, and that phenomena such as ESP are imaginary. Sean Carroll, my physics guru, apparently believes in determinism, and it makes sense to me. The hard part in physics is admitting that some of the techniques used by physicists to explain reality actually disguise the fact that certain aspects of it are not fully understood. Thus, I now think that true randomness does not exist; randomness is a fudge factor disguising the fact that we don't have the necessary techniques or computational power, and perhaps never will, to provide a detailed description of every event in the universe from the Big Bang onward. My own reasoning is that without a rigid coherence to the universe, it would be too unstable to produce stars and planets, let alone organisms. There is a deep coherence to the universe which I think would be shattered by truly random events.

I have also thought about determinism as it pertains to free will. Ultimately, I was unable to reconcile the existence of free will with the science now associated with Darwinism. Natural selection is a mechanism that produces organisms which survive in their environments, and all living organisms are comprised of certain characteristics that could not be otherwise. As the most cognitively advanced animals, we have a tendency to think that there is some magic ingredient that only we possess. That ingredient, it is said, might be consciousness or free will. My view is that our brains have simply evolved a few tricks that give us an advantage over other organisms, and that, in a broad sense, we're not that different from other mammals. I have little doubt that in due course all of the "higher" functions of Homo sapiens will be linked to ordinary evolutionary processes and DNA. The conceptual problems associated with consciousness will disappear when it can be described with greater precision as an evolutionary adaptation, or at least as a byproduct of an evolutionary adaptation.

Plomin only slightly touches on these topics, but he is engaging in an important demystification process that could eventually help produce better ways of organizing society by taking into account the innate differences between people. Later chapters, which I haven't read yet, look more closely at personality traits and DNA associations. Thankfully, Plomin, unlike some other science writers, is interested in the policy implications of this work, and I am looking forward to reading what he has to say. He has done groundbreaking research which will put to rest some of the ideas that have been circulating unquestioned for decades in politically correct circles, which are often composed of well-educated people who tend to ignore science. The book isn't that long, and I'll probably finish discussing it on my next post.