June 21, 2005

Are Political Orientations Genetically Transmitted?

A recent article in the American Political Science Review (APSR) by John R. Alford, Carolyn L. Funk, and John R. Hibbing claims that political orientation is, to some extent, genetic. The New York Times reviews the APSR piece here. A number of bloggers are also commenting on the piece, however, what they respond to is not the APSR article, but the New York Times review of the article. Since I am a subscriber to the APSR (yes, I know, hard to believe) I thought it might be worth something to throw in my two cents. After all, I seem to be the only blogger who's actually read the study (although I can't say this definitively, e-mail me or send a trackback if you also have read it).

I normally avoid this kind of discussion at this blog, but the topic was just so compelling.

The purpose of the article is summed up by the authors:

"In this article, we combine relevant findings in behavioral genetics with our own analysis of data on a large sample of twins to test the hypothesis that, contrary to the assumptions embedded in political science research, political attitudes have genetic as well as environmental causes."

The literature review for the piece sums up what all political scientists already know, namely that:

"Conspicuously absent is consideration of the possibility that certain attitudes and behaviors may be at least partially attributable to genetic factors."
The worry from many quarters from this type of research would be that to say genetics has something to do with political leanings would be deterministic. This troubles our Western sensibilities which are based upon the assumption that choice is an inherent attribute of humanity. However, the authors caution against reading determinism into genetic analysis:
Still, the connection is rarely so simple that a given genetic allele can be seen as causing a certain behavior. More typically, findings in modern behavioral genetics reveal the effect of genes to be interactive rather than direct, let alone determinative.
In other words, genetic predispositions are by no means deterministic. Genetics influences the way we think about the world, but does not determine our outlooks. As the authors summarize the argument:
The issue is not nature versus nurture but the manner in which nature interacts with nurture.
Next the authors move on to methodology. Julian Sanchez, who I presume has not read the actual research study, critiques it this way:
Count me a little skeptical: For one, unless these are studies on twins raised apart, you need to account for the fact that being raised as someone's identical twin is a difference in family environment that could conceivably shape one's attitudes in various subtle ways.
Very good criticism. However, the authors anticipate this objection and respond in kind:
Other evidence against the exclusive environmental argument is that the empirical results suggest MZ twins reared together are often less likely to share behavioral traits with their twins than are MZ twins reared apart, presumably because of extra efforts to establish distinct identities when the twins live together. In addition, as adult MZ [identical] twins living apart age, they tend to become more, not less, similar (Bouchard and McGue 2003), a finding that is difficult to reconcile with the belief that only the environment matters.
Further, since most parents are not aware whether their twins are identical or fraternal (controlling for sex, of course) then if MZ twins are closer politcally than DZ [fraternal] twins, genetics might be responsible.

The authors do not argue that genetics makes one a Republican or Democrat. Indeed, people like me who are Libertarian with Republican leanings may not fit at all into the study if such were the assertion. Rather, they base the study on the notion that certain character traits are to some extent inherited. Character traits such as openness in turn are translated into social attitudes. These social attitudes are then transformed, to some extent, into political attitudes and later into political behavior. The genetic component, they predict, should be an important factor but certainly not the only one or even the most important one.

The image below is Table 1 of the study (I have the study in both .PDF and .html versions). Click on the image for a larger version. The variables are controlled for sex since obviously fraternal twins sometimes are of opposite sex.

As you can see, genetics seems to account for a high of percentage of the correlations between twins.

One very interesting piece of information is the difference in correlation between Republicans and Democrats among fraternal and identical twins. While identical twins opinions about Republicans and Democrats is almost precisely the same (.48 correlation for Republicans .47 correlation for Democrats), the same does not hold true for fraternal twins (.30 correlation for Republicans and .34 correlation for Democrats). Using the authors' methodology, inherited traits account for a whopping .36 for attitudes people have of Republicans, while only .26 for attitudes people have of Democrats!

Why genetics would affect attitudes people have of Republicans more than Democrats beats me. Such inconsistencies obviously must be either explained or are evidence of a major flaw in the study.

Further, the data pokes serious holes at the author's underlying theory. The theory, you will recall, is based on the notion that certain personality traits, such as openness, would eventually translate into political attitudes. However, when one looks at the data one immediately notices the apparent random nature of the distribution of attitude correlation.

Why, for instance, would genetics account for a large portion of people's attitudes towards property taxes but not for divorce or gay marriage?? What inherited attitude would have anything to do with mundane taxation issues, yet not account nearly as much for issues of serious social change?

The authors further analyze genetic influences by coding each response as either "conservative", "neutral", or "liberal". An addidive scale is created using the 28 questions on the survey. The higher the score the more conservative, and vice versa. Table 2 below is obtained by running a standard Pearson's correlation coefficient. Click on the image for a larger view.

The above Table indicates that heredity seems to account for correlations on the constructed conservatism scale far more than the enviroment. What is even more shocking is that heredity seems to be even more important in explaining variation than educational attainment or party identification!

A not-so-surprising finding is the opinionation variable. Opinionation was measured by how often a respondent chose either the liberal or conservative response--in other words, opinionated people rarely are 'neutral' on these types of questions. Heredity seems to explain why some people are far more opinionated than others!

Another not-so-surprising finding is that party identification cannot be explained by the genes, scoring the lowest (.14) correlation.

One other observation made by Julian Sanchez is also explained by Table 2. Speaking of the NY Times article which he read, Sanchez notes:

The article closes with the chilling observation that, since people tend to seek out ideologically congenial mates, genetic concentration of this sort may well be increasing. Yep, the zealots you see on the party convention floors? They're breeding.
And that is, indeed, the inference the NY Times makes from the second set of numbers in the above Table. However, that is not exactly what the table means.

Using identical surveys filled out by a subset of the twins' parents, they attempt to control for 'assortive mating'. Assortive mating happens when you marry some one with similar political views. For instance, Frank J. married Sarah K. not only because she's cute and is great at cleaning showers, but because of similar beliefs about gun control. Same goes for Mike Williams and her Sporkness.

Unfortunately for the New York Times, though, the authors do not conclude that assortive mating is having a huge impact (I'll return to this later). They describe the affect as 'moderate'. So, no mutant uber-consrvatives walking the moonless nights seeking liberal brain should be expected in the near future.

However, the socialization effect + the genetic affect does lead to a cumulatively important influence. But if one were to seperate future IMAO twins at birth and raised by adoptive parents, there might be some reason to hope they may turn out semi-normal!

Table 3 below uses data from twin studies in Australia to see how valid the results would hold across cultures. Click on the image for a closer view.

While most of the items show similar patterns of correlation between U.S. and Australian twins, two do not. Immigration produces a very large correlation in U.S. twins but a rather weak one (non-white immigration) among Australians. The same is true of the socialism variable.

If genetics predisposed one to political attitudes how can that be explained?


The article is a seminal one in that it, for the first time, raises the possibility of exploring genetic reasons for political attitudes and behaviors. For years, political scientists have speculated that genetics played a component in political behavior. However, such conversations were often held behind closed doors and never in a peer reviewed journal--especially the flagship journal of the field.

Why? You recall the outcry against Larry Summers, the President of Harvard University, when he merely brought up the subject that genetics may partially explain why there are less women in the hard sciences. The world of political science is far more politically correct and twice as quick to condemn any notion of genetics in slippery-slope arguments that inevetably lead to holocaust comparisons.

Trust me, within the week we will see a number of political scientists compare this research to Spencer's Social Darwinism, reinforcing dominate patriarchal paradigms, eugenics, and as the kind of thinking that led to the holocaust. Yes, it is that bad.

For instance, in the work's concluding remarks, the authors use several hypotheticals for explaining how genetics can influence political opinions by operating at the 'gut level'. Notice how they charaterize 'conservative' gut reactions in negative terms, but 'liberal' gut reactions in positive terms:

One is characterized by a relatively strong suspicion of out-groups (e.g., immigrants), a yearning for in-group unity and strong leadership, especially if there is an out-group threat (“Do not question the President while we are at war with terrorists”), a desire for clear, unbending moral and behavioral codes (strict constructionists), a fondness for swift and severe punishment for violations of this code (the death penalty), a fondness for systematization (procedural due process), a willingness to tolerate inequality (opposition to redistributive policies), and an inherently pessimistic view of human nature (life is “nasty, brutish, and short”).

The other phenotype is characterized by relatively tolerant attitudes toward out-groups, a desire to take a more context-dependent rather than rule-based approach to proper behavior (substantive due process), an inherently optimistic view of human nature (people should be given the benefit of the doubt), a distaste for preset punishments (mitigating circumstances), a preference for group togetherness but not necessarily unity (“We can all get along even though we are quite different”), suspicion of hierarchy, certainty, and strong leadership (flip-flopping is not a character flaw), an aversion to inequality (e.g., support for a graduated income tax), and greater general empathic tendencies (rehabilitate, don't punish).

It's as if the authors, knowing the reaction of their colleagues, hedge their bets against the worst accusation that can be made in the field: conservative.

And just to show that they are legitimate researchers, they spend a whole paragraph of their conclusion making sure the reader understand they hate President Bush and disdain Republican voters:

Similarly, if a Republican president had committed adultery with a young intern or if a Democratic president had dramatically worsened the deficit and taken the country to war in a far-off land on the basis of undeniably incorrect beliefs about the opponents' nuclear and chemical weapons capabilities, the positions of most voters on the acceptability of these conditions would be completely reversed. Issue positions generally reflect divisions; they do not create them.
Are you starting to get why I blog anonymously?

The authors also add this idiotic assessment to an otherwise fairly written analysis:

If anything, the heritability of orientation in combination with assortative mating may exacerbate the current divide.
This despite the fact that human evolution did not begin a single generation ago? If such assortive mating were to have any long-term political impact then the current divide that many pundits see between liberals and conservatives (who the authors claim are related to 'absolutists' and 'contextualists') then we should have killed each other long ago. If these two phenotypes, as they are called by the authors, have such inherently different views of the world then we would expect that over the very long term, that the world should be getting more violent...and not on account of better weapons, but because of genetics.

The only explanation I have that the authors concluding remarks were able to get through both the peer review and editorial process is that the editors and peer reviewers didn't think to question the odd logic based on the false assumption that America has never been more partisan than now. I'm afraid that those 500,000 Americans who died in the Civil War might beg to differ.....

While the article brings up some very interesting questions, finally liberated from backroom discussion, it should be seen as a beginning point and not an end. Such research in the future, I should hope, will avoid the type of liberal steryotyping used by the authors here in their concluding remarks.

All in all I am left agreeing with Pejman Yousefzadeh who says:

Genetics may very well influence how one behaves in the political sphere, but I think it is unwarranted for people like me to think that we are libertarian-conservatives because of something in our DNA.
NRO's The Corner is having a pretty good back and forth discussion on the study as well, although it is apparent none of them have read beyond the NY Times article either.

Hat tip: Memerandom

UPDATE: Shrink Wrapped has a good analysis of the NY Times reporter's misunderstanding of the underlying science.

Also, since Demosophist is a trained methodologist with a subscription to the APSR maybe he would like to add a few comments here? Same goes for Steve-oh-face and the other Steve, the Poliblogger.....

UPDATE II: Neuro Con has a pretty good analysis here as well.

UPDATE III: Charles Johnson notices this interpretation of the study by the MSM:

It’s not that conservatives mean to favor the rich over the poor and middle class.

And it’s not that they’d rather drill for oil than preserve the environment.

Because it’s not really their fault.

They’re just born that way.

By Rusty Shackleford, Ph.D. at 01:23 PM | Comments |