Endorsing evolution: A matter of authority?
As I discussed earlier in this blog, there appears to be substantial cross-cultural variation in the degree to which people endorse evolutionary theory. According to a study by Miller et al., some countries are characterized by an almost universal acceptance of evolutionary theory (e.g., Iceland, Japan), whereas in other countries (e.g., USA, Turkey), less than half of the population endorses it. This cross-cultural variation seems to result from an interplay between cognitive factors (what cognitive mechanisms underlie our understanding of evolutionary theory) and cultural ones (why do we endorse evolutionary theory).
Several studies indicate that evolutionary theory is at odds with our intuitive notions about the origin of living things. Creationism seems to be (close to) the default position: young children, regardless of their religious background, believe that organisms are products of design, and that creatures are there for a specific purpose (see this paper by Deborah Kelemen). Moreover, people with Alzheimer tend to revert to such forms of teleological reasoning (see this paper by Lombrozo et al.), and even educated adults are vulnerable to it when they are put under time pressure (see this paper by Kelemen & Rosset). Several studies indicate that evolutionary theory is at odds with our intuitive notions about the origin of living things.
Most adolescents and adults do not seem to understand the mechanisms that underpin evolutionary theory, such as natural selection or drift. Bloom and Weisberg (here) suggested that different rates of acceptance of evolutionary theory may be a matter of epistemic trust, i.e., the degree to which we defer to scientific authorities when we utter statements of the type "I believe evolutionary theory is true". Most people are not able to gauge the strengths and weaknesses of current scientific theories (e.g., the theoretical underpinnings and empirical support for general relativity theory or plate tectonics), but rely on experts for their scientific beliefs. A statement like "I believe string theory is correct" is not based on considerations about string theory itself, but rather on the perceived reliability of physicists who developed this theory. The question then becomes: why are Japanese more willing than Americans to trust evolutionary biologists and other scientific experts?
Beliefs that we endorse but do not fully understand are quasi-beliefs (a term coined by François Récanati). Tyler Burge already pointed out that quasi-beliefs are actually quite common. For example, someone can erroneously hold the belief that she has arthritis in her thigh muscles; she can sincerely believe this even though it must be false, since arthritis affects only the joints. Indeed, the truth-value of the utterance "I have arthritis in my thigh muscles" is dependent on how experts (physicians) fill in this term – we can imagine a world where arthritis could be a term that had a different meaning (muscle disease), and in that case the utterance could be correct. Similarly, orthodox Jewish people defer to the expertise of a rabbi or Kosher labels on food packaging in forming their belief about whether or not particular food sources are kosher.
For someone who cannot understand the mechanism of natural selection, the belief that evolutionary theory is correct is a quasi-belief. By definition, a quasi-belief is not fully understood, so judgment about its validity cannot depend much on the content of that belief, but rather on considerations about the reliability of its source. In the USA, the science-inspired belief that evolutionary theory is correct has direct competitors from religious sources, which contend that species do not change over time, and that humans did not evolve from apes. In the USA people can choose to defer either to the expertise of evolutionary biologists, or alternatively, to religiously-inspired pseudoscientists such as young earth creationists. In Belgium, where I live and work, there is a sharp distinction in acceptance of evolutionary theory: whereas most Christians (mostly Roman-Catholics) accept it, many Muslims reject it. This is mainly due to the efforts of Muslim creationists such as Harun Yahya, who publicly challenge evolutionary theory in pamphlets and books that are freely distributed. It is because the poorly understood belief in evolutionary theory has a competitor, a potential source in which people can choose to place their epistemic trust, that the acceptance of evolutionary theory is compromised in Muslims.
Although I know of no quantitative comparisons, I am convinced that Einstein's theories of general and special relativity are endorsed more widely than evolutionary theory (leaving aside the occasional crackpots who claim to have discovered glaring errors in Einstein's original papers). Yet, there is nothing in our intuitive physics that prepares us for these ideas, and very few people possess the mathematical background that is necessary for a full grasp of this theory. By contrast, Darwin's theory can be understood purely verbally (as Darwin himself did). To speculate: if there were a tendency in religious movements in the USA to ask people to critically reflect on Einstein's theories, to give 'equal time' to Einstein and medieval impetus theory (which is in fact closer to our intuitive physics), epistemic trust in current physics would decline markedly. Indeed, flat earth movements enjoyed some modest success in the 19th and early 20th century, although their success was not of the magnitude of that of contemporary creationist movements (that have more money, and more media at their disposal).
The cross-cultural differences in acceptance of evolutionary theory, therefore, does not depend in how far people understand this theory (although understanding would probably help), but rather on the presence of competitors in which people can place epistemic trust.