Chris Mooney, evolution, and politics

Chris Mooney is back with a new book, The Republican Brain, and that means we’re going to be subject to the hard sell: loud self-aggrandizement in every possible venue.  Be prepared to hear things like “I guess I hit a nerve” when the book is criticized, as I am about to do. Note, though, that I haven’t read the book yet—it hasn’t been released—so my comments are based on Mooney’s summary of its thesis at HuffPo (in the Science section!): an essay called “Want to understand Republicans? First understand evolution.”

Mooney’s thesis is that the difference between conservatives and liberals is based on differences in their genes, and that those differences are reflected in physiology (we’ll get to the evolution part in a bit):

Santorum’s absurd global warming conspiracy theory is the kind of thing that absolutely outrages liberals — but to my mind, they really ought to be getting used to it by now. From global warming denial to claims about “death panels” to baseless fears about inflation, it often seems there are so many factually wrong claims on the political right that those who make them live in a different reality.

So here’s an idea: Maybe they actually do. And maybe we can look to science itself — albeit, ironically, a body of science whose fundamental premise (the theory of evolution) most  Republicans deny – to help understand why it is that they view the world so differently.

In my last piece here, I commented on the growing body of research suggesting that the difference between liberals and conservatives is not merely ideological in nature. Rather, it seems more deeply rooted in psychology and the brain — with ideology itself emerging as a kind of by-product of fundamentally different patterns of perceiving and responding to the world that spill over into many aspects of life, not just the political.

To back this up, I listed seven published studies showing a consistent set of physiological, brain, and “attentional” differences between liberals and conservatives. Later on my blog, I listed no less than eleven studies showing genetic differences as well.

The papers cited by Mooney do show some genetic evidence that differences in social and political attitudes have a reasonable genetic component (quantified as “heritability”: roughly the proportion of variation in social attitudes that is explained by variation in genes), though some work suggests otherwise. And, of course, there is also a large cultural component to social attitudes as well: conservative parents inculcate their kids with conservative values, and so on.

The genetic and cultural components can be separated by either adoption studies or twin studies. The latter have their own problems, since a greater similarity of political attitudes among identical than among fraternal twins (the evidence often used for a genetic influence) can be explained by both more similar genes—identical twins have identical genes, fraternal twins share half their genes—or more similar environments, since identical twins tend to hang around with each other more, are treated more alike, and in general experience more similar environments than do fraternal twins. It appears that a lot of Mooney’s data indeed rest on higher correlations of political attitudes between identical than fraternal twins.

I find the physiological and some of the psychological differences even less convincing. If there’s a difference in skin conductance or brain physiology between conservatives and liberals, or in the way that they react to pictures of Bill and Hillary Clinton (that was one test!), this could be a consequence rather than a cause of political attitudes.  That is, the “biological” differences need not be involved in the causation of poltiical attitudes, but be an inevitable result of adopting a set of political attitudes, whether that adoption be due to the influence of environments or genes. Your brain lights up in new ways when you drink coffee, or see a new love, but those brain patterns are the the result of drinking coffee or being in love, not a cause of those phenomena.

Mooney goes on to characterize differences between liberals and conservatives as reflecting fundamental life strategies, and that’s where the evolution bit comes in.

As the new research suggests, conservatism is largely a defensive ideology — and therefore, much more appealing to people who go through life sensitive and highly attuned to aversive or threatening aspects of their environments. By contrast, liberalism can be thought of as an exploratory ideology — much more appealing to people who go through life trying things out and seeking the new.

Note that that conclusion is based on a single published study in the Philosophical Transactions of the Royal Society (a journal I consider good but not outstanding). Mooney continues:

To show as much, the Nebraska-Lincoln researchers had liberals and conservatives look at varying combinations of images that were meant to excite different emotions. There were images that caused fear and disgust — a spider crawling on a person’s face, maggots in an open wound — but also images that made you feel happy: a smiling child, a bunny rabbit. The researchers also mixed in images of liberal and conservative politicians — Bill and Hillary Clinton, Ronald Reagan and George W. Bush.

While they did all of this, the scientists measured the subjects’ “skin conductance” — the moistening of their sweat glands, an indication of sympathetic nervous system arousal — as well as where their eyes went first and how long they stayed there.

The difference was striking: Conservatives showed much stronger skin responses to negative images, compared with the positive ones. Liberals showed the opposite. And when the scientists turned to studying eye gaze or “attentional” patterns, they found that conservatives looked much more quickly at negative or threatening images, and spent more time fixating on them. Liberals, in contrast, were less quickly drawn to negative images — and spent more time looking at positive ones. . .

As the authors concluded, “The aversive in life is more physiologically and cognitively tangible to some people and they tend to gravitate to the political right.”

Note again that this shows a difference is psychology and physiology, which could be a result rather than a cause of political attitudes.  And there is no genetic analysis of the difference in attitudes.

Mooney concludes, then, that liberals are a bunch of soft-nosed tree-huggers and bunny lovers, while conservatives are alert and wary, easy to perceive threat.  Where does the evolution come in? Because Mooney suggests that those differences, to the extent that they’re genetic, arose by natural selection.  Not only that, but “liberal” genes are less adaptive than “conservative ones”!:

The big question lying behind all this, of course, is why some people would have stronger and quicker responses than others to that which is perceived as negative and threatening (and disgusting). Or alternatively, why some people — liberals — would be less threat aversive than others. For as the University of Nebraska-Lincoln researchers note: “given the compelling evolutionary logic for organisms to be overly sensitive to aversive stimuli, it may be that those on the political left are more out of step with adaptive behaviors.”

“Compelling evolutionary logic,” of course, is not data: it’s just the perceived ability to make a convincing story. I could easily make a story about why it’s more adaptive for people to smile at bunnies than to frown at Bill Clinton: perhaps that is a byproduct of devotion to one’s children and family, which is also adaptive.  The point, though, is that we have no idea a priori which sort of behavior is or was adaptive in the evolutionary sense of conferring reproductive advantage, and absolutely no data on the reproductive output of liberals versus conservatives.

And thus are we drawn to the only context in which we can make any sense of any of this — the understanding that we human primates evolved. As such, these rapid-fire responses to aversive stimuli are something we share with other animals — a core part of our life-saving biological wiring.

And apparently, they differ in strength and intensity from person to person — in turn triggering political differences in modern democracies. Who knew?

There is a thicket of problems here.  If conservative genes are more adapted (presumably because they enable their bearers to recognize and respond to threats more readily), why are there so many liberal genes still around?

In other words, what explains the pervasive variation? Usually, when geneticists see substantial variation in traits, like the frequencies of alleles for loci involved in histocompatibility, and we assume that these differences do make a difference in evolutionary fitness, we seek explanations for the variation itself: why do two (or more) types persist in a population?  If one type is better than the other, as Mooney suggests conservative genes are, why hasn’t that type come to nearly take over the population?  Evolutionists need other explanations to explain pervasive genetic variation. Historically, these explanations involve different variants having different fitnesses (reproductive output) in different environments, or at different times. Or perhaps the variants are maintained by “frequency-dependent selection”: when one form of a gene becomes rare, it gains and advantage over the other one.  “Liberal genes”, for example, could confer a reproductive advantage in a population that is largely conservative. (I see no reason why this should be so.) Finally, perhaps people carrying both types of genes (“heterozygotes”) are fitter than those carrying only one type (“homozygotes”).

The point is that one can’t just adduce “evolution” as a cause of variation, because only certain types of natural selection will maintain variation in a population.  The most commonly conceived type of selection—”directional selection,” in which one type of gene causes its bearers to have more offspring than the other—leads to the elimination of variation, not its persistence. That persistence is what needs be explained under Mooney’s “evolution” hypothesis.

And of course there’s the perfectly plausible alternative that being conservative versus liberal has no significant effect on reproductive output: that is, the traits are (or were in our ancestors) evolutionarily “neutral.” In that case one need not confect any adaptive explanation.  Or, “political genes” could have been subject to some sort of selection in our ancestors (not necessarily because of their effects on politics!), but selection that no longer operates. The first step in any real evolutionary study would be to assay reproductive output in modern populations of conservatives versus liberals, but of course that doesn’t address the question of why those traits evolved (if they did) in our long-dead ancestors.

In the end, Mooney draws two unwarranted conclusions from the data. The first is that the evidence for genetic/physiological differences supports the need for political tolerance between liberals and conservatives.

The Nebraska-Lincoln scientists interpret their results as a powerful argument in favor of greater political tolerance and understanding — and I agree with them. Politics isn’t war, and it isn’t zero sum. It requires negotiation and compromise. Surely our public debates should be guided by something more than threat responses and fight-or-flight.

So how do we get beyond our political biology? Well, the implication for liberals seems obvious: If they want to fare better politically, they need to learn to go against their instincts and stay focused and committed.

None of this has anything to do with genetics. You could draw identical conclusions even if the differences between conservatives and liberals were purely based on differences in their environment and social development. This is just a warm, fuzzy conclusion that is independent of science, and based purely on political observation and a desire to appear concilatory.

And I don’t necessarily agree with that conclusion, either, because compromise isn’t always warranted. Did Democrats compromise on civil rights in the Sixties, and should we compromise on gay rights now? And are liberals really less focused and committed? Maybe we are now since we have our own president, but we were pretty damn committed and focused when Obama was running against McCain.  This is all typical Mooney-ism, where he, like Elaine Ecklund, draws unwarranted conclusions from scientific data. It’s opinion perfumed with the odor of science without that science really supporting it.

And, of course, the remedy is that we have to teach more evolution—Mooney’s second error.

And the lesson for conservatives? Well, here it is tougher. You see, first we’d have to get them to accept something they often view as aversive and threatening: The theory of evolution.

That assumes, of course, that evolution is responsible for differences between liberals and conservatives in the first place—a conclusion not at all supported by Mooney’s data. And even if those differences were based on evolution, what would that have to do with the political strategies we should adopt now? Neither genetic nor evolutionary differences in traits tell us whether the persistence of those traits is inevitable (a point that Steve Pinker makes eloquently in his latest book), nor how to heal those differences—if we want to.

Yes, there may be genetic differences between liberals and conservatives, but even if the heritability is around 50%, as suggested by one study cited by Mooney, that still means that the other half of the variation in political attitudes is due to variation not in genes but in environments.  Why concentrate on the genes, which we can’t change, on the environments, which we can?

But in the end, evolution seems largely irrelevant here.  At least in Mooney’s post, it appears to be a very fragile hook on which to hang his thesis.  But we’re used to that intellectual strategy from him.

I’ll have a look at Mooney’s book when it comes out in April.  But from this article—and my previous experience with many about issues like Mooney and Kirshenbaum’s book Unscientific America and the “Tom Johnson” affair at their website—I’m not hopeful.  Yes, Mooney may think that Republicans need to accept evolution—and they do, like everyone else—but if Mooney thinks that’s going to breach the political gap, and if is going to throw around genetic studies to support his thesis, he’ll have to learn about evolution himself, and in a more sophisticated way.


  1. lancefurd
    Posted December 31, 2012 at 12:07 pm | Permalink

    Again, sorry, credit where due.

    The study is called “economics knowledge by ideology” and is by Psychologist Zeljka Buturovic of Columbia University and Danield Klein, Professor of Economics at George Mason University.

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