“Not a choice” != “genetic”

by Andrew Gelman on July 14, 2011 · 14 comments

in Campaigns and elections,Education

Political scientists have a pretty clear understanding that we our decisions are influenced in many ways. Just ‘cos something runs in the family, it doesn’t mean it’s genetic. Twin studies etc. I became aware of the distinctions several years ago when teaching a class on left-handedness. According to the statistics we saw, identical twins do not have to have the same handedness, and it’s hypothesized that handedness is determined in the fetal environment. Lots of important things happen during those first nine months.

It’s worth remembering, though, that these distinctions are often lost on the general public and their representatives. Here’s Republican presidential candidate Tim Pawlenty on TV, responding to interviewer David Gregory’s question if “being gay [is] a choice”:

PAWLENTY: Well, the science in that regard is in dispute. I mean, scientists work on that and try to figure out if it’s behavioral or if it’s partly genetic –

GREGORY: What do you think?

PAWLENTY: Well, I defer to the scientists in that regard.

GREGORY: So you think it’s not a choice? That you are, as Lady Gaga says, you’re born that way.

PAWLENTY: There’s no scientific conclusion that it’s genetic. We don’t know that.

My point here is not to mock Pawlenty—after all, you could probably dig up a candidate or two who disputes the theory of evolution, which would pretty much shoot down the idea of asking the advice of scientists on anything. And I seem to recall that Jimmy Carter saw a UFO once. And didn’t Ronald Reagan schedule some important meeting based on the advice of his wife’s astrologer? Let’s just hope John Travolta and Tom Cruise never run for office. . . .

Anyway, as I was saying before I got distracted, my goal is not to mock but rather to emphasize that, to the great uneducated masses out there, people think of “genetic” as just another word for who they are in their bones. As researchers, we should be aware of this confusion.

{ 14 comments }

Gregory Rose July 14, 2011 at 12:49 pm

It’s also a good excuse for relatives who don’t like what they see from someone from the same family!

Darren Schreiber July 14, 2011 at 3:01 pm

People doing studies of heritability use the ACE (Additive genetic, Common environment, and unique Environment) model which does not really provide a good framework for thinking about choice in a meaningful way. In this framework, all behavior is essentially categorized as genetic or environmental (or some interaction of those). As a modeling decision, I understand why this is done, but it unintentionally takes a metaphysical position with consequences for our sense of who we are “in our bones” as well as the responsibility we assign to the behaviors of others (e.g. being gay, being obese, or committing crimes.)

The actual science being done on the role of genetics and environment is proving to be more and more nuanced. If a male suffers from severe malnourishment, this can have effects that are passed to its children and grandchildren, without actually changing the genetic code and though the only connection to the descendants is through the contribution of sperm. This and other epigenetic phenomena (like fetal environment) perhaps help to explain a part of the “missing heritability” problem where estimates from twins studies are vastly higher than the explanatory power found using techniques like genome wide association studies (GWAS).

By the time we get to the neural level (where the who we are “in our bones” issue is also critical) the problems get even more complex. Learning to juggle over a few months shows effects on functional brain activity, but it also alters the volume of the grey matter in certain brain areas and changes the connections from one brain region to another (via white matter). These effects are large enough to be easily detected using imaging tools with fairly poor resolution.

My understanding of this broad range of literature is that we are “hardwired to not be hardwired” (the title of the second chapter of my current book project). If we are as capable of flexibly adapting to our physical and social environments as the research suggests, then our conversations about the role of biology in our human nature will need a restructuring that goes far beyond the mere genes/environment, free will/determinism, blank slate/biological destiny frames that currently exist. My sense is that the confusion is not merely in the general public, but even among careful scientists who are struggling comprehend the deeper implications of this body of work.

Andrew Gelman July 14, 2011 at 3:35 pm

Darren:

Well put. I hope your book helps to reduce confusion in this area.

Michael July 15, 2011 at 10:06 am

To be fair to President Carter, he does not claim to have seen an alien craft. He saw something in the sky that he couldn’t identify, the literal definition of an unidentified flying object.

Mattison July 15, 2011 at 10:54 am

To follow up on Michael, Carter did not claim he saw an alien space craft. He believed it was most likely a military air craft. Investigators think it might have just been Venus. He was interviewed about it on Skeptics Guide to the Universe a couple years ago:

http://www.theskepticsguide.org/archive/podcastinfo.aspx?mid=1&pid=105

Andrew Gelman July 15, 2011 at 12:04 pm

Next you’re gonna tell me that Al Gore didn’t really invent the internet!

Rieux July 15, 2011 at 12:16 pm

Maybe we can call this “the genetic fallacy.”

Well, we probably shouldn’t, because the idea came from Tim Pawlenty, and he’s a doofus.

zrzzz July 15, 2011 at 8:02 pm

Homosexuality has huge advantages for a population, so it’s not a stretch to believe it evolved, but it could never be a single, identifiable gene (How are you going to pass on a gene if you never have babies!). It has to be like a flash mob. The bits of it are always there and it just happens when the time is right. We’re all a little fabulous inside. Embrace it!

BobNH July 16, 2011 at 7:22 pm

Are you saying homosexuals never have babies?
So those people who say they are homosexuals, and have babies, are lying!

Jake July 16, 2011 at 7:17 pm

Well lots of gay people say it’s not a choice and some people develop their libido into a homo erotic direction later and if your bi you always have a choice.

What is the motivation for attempting to quantify these anacdotes, I don’t really care if it’s a choice or not. I just accept people that’s how people are and respect their sexuality.

Andrew Gelman July 16, 2011 at 7:41 pm

Jake:

I think it’s a choice for some people and not for others. I don’t know why people have to put things in an either/or framework. My main point, though, was that something can be “not a choice” without being “genetic.”

Roger July 17, 2011 at 9:43 pm

Gregory is the one to criticize, because he is the one who imposed the “either/or framework”. Gregory insisted on asking an imprecise question for which there is no scientific consensus. Pawlenty said that he defers to the scientists. When Gregory insisted on an answer anyway, Pawlenty tried to answer a more precise version of the question. I do not see any fault with what Pawlenty said.

Andrew Gelman July 19, 2011 at 7:20 am

Roger:

Pawlenty said, “if it’s behavioral or if it’s partly genetic” and then a few lines down identified “genetic” as synonymous with “born that way.” So I do think he’s making the mistake noted above.

Again, I’m not trying to criticize Pawlenty in particular here. My point is that this misunderstanding of genetics is widespread and implicit.

Ilan Dar-Nimrod July 18, 2011 at 8:20 am

Genetic determinism (and essentialism) is an important construct which seem to color social and individual perceptions (of self and others). Steve Heine and I have a paper coming out (Psychological Bulletin) in September that depicts many of the cognitive processes and related outcomes which follow genetic attributions. I append the abstract of the paper. For those who are interested I’d be happy to provide the full paper.

This paper introduces the notion of genetic essentialist biases: cognitive biases associated with essentialist thinking that are elicited when people encounter arguments that genes are relevant for a behavior, condition, or social group. Learning about genetic attributions for various human conditions leads to a particular set of thoughts regarding those conditions: they are more likely to be perceived as a) immutable and determined, b) having a specific etiology, c) homogeneous and discrete, and, d) natural, which can lead to the naturalistic fallacy. There are rare cases of “strong genetic explanation” when such responses to genetic attributions may be appropriate, however people tend to over-weigh genetic attributions compared with competing attributions even in cases of “weak genetic explanation,” which are far more common. Research on people’s understanding of race, gender, sexual orientation, criminality, mental illness and obesity is reviewed through a genetic essentialism lens, highlighting attitudinal, cognitive and behavioral changes that stem from consideration of genetic attributions as bases of these categories. Scientists and media portrayals of genetic discoveries are discussed with respect to genetic essentialism, as is the role that genetic essentialism has played (and continues to play) in various public policies, legislation, scientific endeavors, and ideological movements in recent history. Last, moderating factors and interventions to reduce the magnitude of genetic essentialism are discussed that identify promising directions to explore in order to reduce these biases.

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