Well, I always take those surveys with a pinch of salt.
Why? The sample size is over 44 thousand people (approx. 1.3k/country), which is nice size. If you are afraid of trolls: they are on both sides, so they mostly nullify each other, and the reminder is unlikely to be huge — even with extreme values like 10% the general image on this chart is not changed. The trolls are expected to reject evolution
(citation needed), so there would be a negative correlation between that and “not sure” if they would inflate the anti-evolution camp numbers. But we clearly have the opposite. I see no reason to not believe that survey unless proven wrong.
But like with the flat Earth thing, the view on evolution in a given country seems pretty strongly related to the relative importance of religion in said country. So this is not very surprising at all.
Contrary to what you may have implied above, the why and how for those topics are strongly related for many people.
The very same research doesn’t support that. First of all, there is a difference between US and European countries in correlation between various factors and the answers, which means that there is no single, one-factor model suitable for the whole world. For US the main factor seems to be the hijacking of the discussion by politicians — which, unsurprisingly, is the expected primary factor not only for accepting evolution. While in US there is solid correlation between fundamentalist religious views and rejection of evolution, it is not covering non-fundamentalists, it is much weaker in Europe and there is a known causative relation that goes from politics to religious views which explains the correlation. Finally, everywhere there is correlation between literacy and rejection of evolution, which — again — has known causative relation associated with it.
(1)Anyway, let’s see the data. For all the countries from this research, I have charted percentage of evolution supporters and the corresponding percentage of religious people. Data based on CIA Factbook, with the exception of Denmark, for which I used whatever Wikipedia provided. 3 countries marked with red squares, Denmark included, have uncertain data due to various factors.
(2)The only thing that clearly increases with the amount of religious people is variance.
Do not oversimplify things. In particular things as complex and having as many mutual dependencies and feedback loops with other subjects as religion does.
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(1) Literacy is a proxy for education, which increases amount of scientifically proven knowledge compared to knowledge of other kind. You may try to disprove the last statement though, as I don’t really recall ever seeing any research that would confirm that — it is taken for granted that education has that effect.
(2) E.g. Turkey, depending on the source used, varies between 0% (unrealistic official data) to 13%, and those values may or may not include or miss people who should be counted as non-religious.