Americans don't believe in evolution, but why?

The depressing fact that half or so of American adults reject any notion of evolution has been documented by survey after survey. So has the fact that Europeans don't seem to have a similar problem with Darwinian theories. What is much less clear is why there is such discrepancy. As a European, I would love to tell you that this is because Europeans are so much more understanding of the principles of science, but I know that that is simply not the case. What then?

A recent study by Miller, Scott and Okamoto published in Science (11 August 2006) begins to unravel the mystery, data in hands. While the results are not actually surprising for anyone attuned to the political and religious ideological differences between the Old and the New worlds, it is nice to have solid quantitative evidence, rather than just personal intuitions backed up by the occasional anecdote.

First off, Miller and colleagues document once again the basic facts, this time using surveys in the US, 32 European countries (including Turkey, which technically is not part of Europe), and Japan. The findings include the rather worrisome (though, again, not altogether unexpected) observation that “only Turkish adults were less likely to accept the concept of evolution than American adults.” As we used to say when I was living in Tennessee and wanted to feel better about the sorry state of public education in that state (often ranking at n. 49 out of 50), “Thank God for Mississippi!” (which was often ranked n. 50).

Miller and co-workers went beyond the surveys and hypothesized that certain cultural variables, such as degree of fundamentalism religiosity, political conservativeness, and ignorance of basic science, would account for a significant proportion of the difference between American and Europeans in their attitude toward evolution. To test such hypotheses, they used a statistical technique known as structural equation modeling (SEM), a way to build mathematical models representing competing hypotheses and comparing them quantitatively. SEM cannot prove the correctness of a particular hypothesis (indeed, philosophically speaking, no empirical proposition can be proven with complete certainty), but it is an excellent first step toward assessing how well the available data fit whatever causal models the investigators think reasonable to consider.

Enough with the theory, let's get to the fun part. First off, religious belief. It turns out that the effect of fundamentalist religious beliefs on one's attitude toward evolution is twice as strong in the US than in Europe; Americans really are influenced by their strict religiosity more than their European counterparts. Second, political positions. Again, Miller et al's intuitions were supported by the data: pro-life attitudes – which in the US are more strongly associated than in Europe with the political platform of conservative parties – made it significantly more likely for someone to reject evolution. Moreover, if one self-identifies as a conservative, one is also more likely to both hold fundamentalist religious views and be pro-life, and the two factors add to each other's effect in decreasing one's acceptance of evolutionary theory. Finally, science literacy. While overall understanding of the basic facts of genetics was actually slightly higher among Americans than Europeans, there was a definite positive relation between such understanding and acceptance of evolutionary theory. In other words, the more one knows about science, the less scary evolution becomes. The bad news is that less than half of Americans can provide a basic definition of DNA...

So, all we need to end the creation-evolution controversy is to increase science literacy, decrease religious fundamentalism, and defeat the Republicans at the next elections. OK, folks, we got the knowledge, time to roll up the sleeves and get into action!