Following on the Pope post, there are various theories about whether people might reject evolutionary theory because it contradicts their intuitions. One was described by developmental psychologist Paul Bloom in an article he wrote for Natural History magazine entitled “In Science We Trust.” Bloom, who lays out a theory of intuitive mind/body dualism in his book Descartes’ Baby, believes that we have intuitive “theories” about physics and agency which cause us to operate as though they’re inherently separate things. Following from that, he basically argues that we may reject or misunderstand evolution because we have a hard time imagining something conscious being made out of non-conscious things (that is, consciousness as an emergent property), or that evolutionary change could happen without conscious guidance. This doesn’t make it impossible to understand and accept evolution– of course, since plenty of us do just that– but it would suggest that we have some built-in biases in our thinking which predispose us against doing so. Bloom writes:

A minority of Americans subscribe to an unusual theory about the origin of people and other animals. They are often adamant about the truth of this theory, and believe that it is the only one that should be taught to children. But if you press them on the theory’s details, their answers are muddled. It turns out that these people understand little of what they are defending; they are just parroting back what they have heard from others. Who are they?  They are Darwinians–people who claim to believe in evolution by natural selection. . .  Psychologist Deborah Kelemen of Boston University, for instance, finds that children insist that everything has a purpose. Educated Western adults believe that human-made artifacts have purposes (cars are to drive around in) and that body parts have purposes (eyes are for seeing), but young children take this further, saying the same for animals (lions ate for being in the zoo) and for natural entities (clouds are for raining).  And psychologist Margaret Evans of the University of Michigan found the most direct evidence for natural-born creationism. She carried out a series of studies in which she asked children flat out where they believe animals come from. Their favorite answer is God. That is true of children whose parents are fundamentalist Christians–no surprise–but it is also true for children whose parents accept the theory of natural selection! Evolutionary biologist Richard Dawkins was right to complain, then, that it seems “as if the human brain were specifically designed to misunderstand Darwinism.” . . .   Looking within the United States, the difference between Darwinians and creationists does not reduce to smarts or education: studies of college students found no difference in how well (or poorly) they understood the theory of evolution, whether they believed it was true of not and no matter how much biology they’d studied. When researchers asked the students who endorsed Darwinian beliefs to explain the theory of natural selection, their answers were on average no more accurate than those of the students that rejected evolution. Many in each group misunderstood the theory, coming up with something closer to Lamarck’s view than Darwin’s.   So while an evolutionary biologist might argue that giraffes evolved long necks because the ones with longer-than-usual necks got more food from trees and hence tended to have more offspring, many students would say that it is useful to have a long neck and so (somehow) giraffes will have longer-necked children. They believe, as Lamarck did, that there is some mysterious force that causes animals to become better adapted to their environments, and they confuse this with modern evolutionary biology.  

Those are just a few excerpts; you can read the whole thing for free at the link above. I don’t find it at all surprising to think that there are plenty of people who profess to accept evolution but don’t actually understand evolutionary theory. I wouldn’t be surprised, for that matter, if such people constitute the majority of evolution-accepters. The idea of inheritance of acquired characteristics which Lamarck advocated just seems to be easier for people to grasp whether they are pro-evolution or not. The matter of why some people find this misunderstanding of evolution perfectly okay and others abhorrent does not seem to be about who is more educated or who thinks more critically per se, but very likely more about religious and/or political affiliation. That’s my thought, but I don’t have the research to back it up…yet.

In the meantime, people advocating that evolution should be taught in public school science classrooms and never creationism should sit down with a cup of tea and a copy of Darwin’s Dangerous Idea if they’ve never done so. Consider it an intellectual gift to yourself.