From correspondence between me and a group of very accomplished and reflective researchers who are not examining "acceptance" of human evolution:
What does it actually mean for someone to "believe in" evolution or "accept" evolution independently of how that person answers the belief/acceptance question as it is typically posed in an opinion poll or (invalid) "science literacy" quiz?
In general, is it sensible-- philosophically or psychologically-- to characterize as being the "same type of mental phenonomon" (1) an intentional state that reflects assent to or affirmation of some factual proposition that has no connection to any activity other than exactly that -- a disposition to express assent or affirmation to a survey or quiz item; and (2) an intentional state that reflects assent to or affirmation of some factual proposition that enables some independent, goal-focused activity?
E.g., right now I "believe" or "accept" that I'm sitting in a chair in front of my computer. That belief is bundled in w/ a bunch of intentional states that enable me to correspond with you.
At the same time, if I check some registry in my mind, I can confirm I "believe" that "Columbus sailed to America in 1492." But that "belief" isn't enabling me to do anything; I never use it to anything, in fact.
I'm sure there's some meaning in the proposition "Columbus sailed to America in 1492" & some meaning in the proposition "I believe Columbus sailed to American in 1492." But I think it is facile to say that the intentional state that characterizes my assent to that proposition is the "same kind" of intentional state that characterizes my assent to the proposition that I'm sitting in a chair right now.
If those are "different kinds" of intentional states, then which of those two or which third one are you interested in studying when you try to explain "nonacceptance" of evolution?
If the intentional state you are interested in studying, moreover, isn't one that enables someone to do things (scientific research on the natural history of humans, practice certain types of medicine, educate science students, transmit scientific information etc) that can be done properly only with an "action-enabling" sort of assent in evolution-- why exactly do you want to explain that?
I'm not saying there can be no worthwhile answer to that last question -- just that, by hypothesis, the answer can't be that you are trying to explain variance in any sort of intentional state necessary to do anything that depends on "accepting" the best available evidence of the natural history of human beings.
Would it be bothersome to discover that the form of intentional state of "acceptance" that is measured by the "46% believe..."opinion poll finding is one that has nothing to do with enabling anything? Or anything other than conveying that one has the sort of cultural identity enabled by answering a survey or "science literacy" quiz item in a particular way by persons who either never do anything that depends on using the best evidence of the natural history of human beings or who do assent to or believe in evolution when they are doing those things?
I'm pretty sure most scholars who conceive of "nonacceptance of evolution" as a "problem" to be "solved" never think about these things. I think that is itself a phenomenon that it would be interesting to study!
But in any case, I am pretty sure it is not possible to chart a reliable course for a research program here w/o having satisfactory answers to these questions.