Many of the people I socialize with in “real life” have a biological sciences background. That being said, a relatively deep understanding of ncRNA does not give you any better sense of behavior genetics than the person off the street. And of course when you have a small child conversation often goes in the direction of how you want to raise the child so as to maximize their outcomes. Setting aside the particular normative valence of those outcomes, I am always struck by the power people think parents have over their child’s life path. This is not to say parents don’t have power. There are many young people who have college degrees because of parental expectations. Or, perhaps more precisely the social expectations which the parents set in motion by selecting the milieu of one’s children. Yet so many times I’ve been in a conversation where the phrase “I lean toward nurture” has come up. These are not dogmatic “blank slate” individuals. Rather, they are simply falling back upon the null or default of our age.
But for me here is the irony: I think it is arguably the case today we live in a world where nurture matters far less in variation in outcome of exactly the people who ‘lean toward nurture.’ Let me repeat: when you remove environmental variation by providing a modicum of comfort , you are left with genetic variation! There were times in the past when ‘nurture,’ in other words the hand that environment dealt, was much more influential. And yet during those periods it was nature which was ascendant.
In 2004 the General Social Survey asked a question where respondents were asked to decide between “genes play major role in determining personality” and “experience determines personality.” For various reasons I do not think that the question was good, but, the responses are illustrative of the unanimity we’ve achieved in American society on some questions.
Many people say that having children gives you a much better sense of the power of genes in shaping behavior. At least in the abstract sense that is not true in my case. I accept the “conventional wisdom” from behavior genetics that “shared environment” (colloquially, parental input) is relatively marginal in effecting much long term change within reason (i.e., if you don’t beat your kid over the head with a baseball bat and such you don’t have much influence).
To review, on many bio-behavioral traits the different choices parents make seem to account for on the order of ~10 percent of the differences you see in the world out there amongst their (biological) offspring. Of the remainder of the variation about half of it is attributable to variation in genes, and the other half to unaccounted for non-shared environment. In The Nurture Assumption Judith Rich Harris proposes that that last effect can be reduced down to social environment or peer groups. Her line of argument is such that parents are important because of the genes they contribute, and, the environmental milieus which they select for their offspring.
On one level I find this banal to review. If it is not the orthodoxy, this position seems relatively uncontroversial, and the results fall out of the data with minimal manipulation. But as a society such facts have simply not been internalized. In the great framing of “nature vs. nurture,” appealing in its stylistic dichotomy, but not even wrong in its substance, the past few centuries have seen multiple swings between each stylized extreme. That has been a matter of ideology, not science. The popularity of public intellectuals such as Steven Pinker by the turn of the 20th century indicates to me that the high tide of post-World War II nurture-über alles has receded. But the media and popular culture are to some extent lagging indicators. They continue to trumpet correlations between parental choices and offspring outcomes as if there is a causal connection without pausing to consider the possibility both might be being influenced by a confound, genes.
Epigenetics is making it “big time,” Slate has a review up of the new book Epigenetics: The Ultimate Mystery of Inheritance. In case you don’t know epigenetics in terms of “what it means/why it matters” holds out the promise to break out of the genes → trait conveyor belt. Instead positing genes → trait → experience → genes, and so forth. Or perhaps more accurately genes → trait × experience → genes. Epigenetics has obviously long been overlooked as a biological phenomenon. But, I think the same could be said for the ubiquity of asexual reproduction and unicellularity! Life science exhibits anthropocentrism. That’s why there’s human genetics, and biological anthropology. My own concern is that epigenetics will give some a license to posit that the old models have been overthrown, when in fact in many cases they have been modified on the margin. Especially at the level of organisms which we’re concerned about; human-scaled eukaryotes. Humans most of all.
The last paragraph in the review highlights the hope, promise, and perils of epigenetics in regards to social relevance: