Science magazine has just published a graph of data taken from a general social survey of Americans that quantifies what most of us assume: a well-educated liberal who is not a fundamentalist is much more likely to accept evolution than a conservative fundamentalist with only a high school education. You can see the trend fairly clearly: here we see the percent believing in evolution vs. fundamentalism, amount of education, and self-reported political views.

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The percentage of respondents believing in human evolution is plotted simultaneously against political view (conservative, moderate, liberal), education (high school or less, some college, graduate school), and respondent’s religious denomination (fundamentalist or not). Belief in evolution rises along with political liberalism, independently of control variables.
It looks to me like being a fundamentalist means you’re about half as likely to believe in evolution as a non-fundamentalist of the same level of education and place on the political spectrum. The majority of fundamentalists of any kind (except the liberal ones with a grad school education; I wonder how many of those there are) reject evolution. To get a majority of conservatives to accept evolution, you have to drag them through grad school and make sure they aren’t fundamentalists.
It’s not surprising that fundamentalism puts such a strong damper on evolution, but it is surprising that political conservatism would do likewise. That, I suspect, is a consequence of the strong association between the religious right and Republicans in this country, and I have to wonder whether conservatives who reject religion completely are as screwed up as this sample indicates, and if conservatives from other countries would do as poorly.
One problem I have with these data, though, is there is no indication of the sample size in each category. It’s taken from a total of 3673 respondents, but I rather suspect that the liberal-fundamentalist category was significantly smaller than the conservative-fundamentalist group in raw numbers, so that, for instance, there are actually many more fundamentalist grad students who disbelieve evolution than believe it.
The chart also shows that a college education has a negligible effect on fundamentalist’s belief in evolution, but what we don’t have here is any data on what kind of college education we’re talking about. The fundamentalists may have mostly attended a bible college that reinforces their ignorance for all we know, and they may have had a very different experience than the non-fundamentalists, who would have been more likely to attend a secular school.
The association of anti-evolutionism with conservatism is not a particularly reassuring trend to me. Despite being liberal myself, I think the acceptance of good science ought to be independent of political affiliation; the data says it isn’t. The chart is about belief in evolution, and that’s a good word for it—if you are saying you agree that humans evolved from earlier species of animals because your political views say you should, you may not be evaluating the evidence rationally…or perhaps liberals are simply more receptive to education.
Mazur A (2007) Disbelievers in evolution. Science 315(5809):187.