For example, a study found that people’s emotional appreciation of religion was negatively related to the more rational or intellectual aspects of Openness, but positively related to artistic imagination and aesthetic sensitivity, two other facets of Openness.
Although this interpretation is based on extrapolation, it still makes sense: first, smarter people tend to be less gullible; second, in most societies religious people outnumber atheists and agnostics - though global levels of religiosity have been declining, and there is substantial cultural variability in religiosity levels.
(3) Intelligence and religiosity are “functionally equivalent”, which means that they fulfil the same psychological role.
Furthermore, there is also ample evidence suggesting that higher Openness may cause IQ gains in adulthood because open individuals are more likely to invest time and resources acquiring expertise and knowledge.
By the same token, it is feasible to expect open individuals to be less interested in religion.
Another way of putting it is that people with a high IQ are more likely to have faith in science, which isn’t religion’s best friends (yes, yes, I do know about Einstein’s quotes).
(2) Intelligent people are less likely to conform, and, in most societies, religiosity is closer to the norm than atheism is.
Since religion tends to eliminate ambiguity and uncertainty, its “utility” or psychological benefits should be greater for less than more open people, which would explain why religion appeals more to less intelligent individuals – who are generally less open. Although there are no meta-analytic studies on the joint or interactive effects of Openness and IQ on religiosity, there are plenty of studies examining the relationship between personality and religiosity.
The first large-scale review reported that Openness is negatively correlated with religious fundamentalism and formal religious adherence, albeit weakly.
In particular, individuals with higher Openness may be generally more reticent to embrace formal religious beliefs – but, on the other hand, people who are extremely open would be more able to understand and tolerate individuals who hold such beliefs, even if they don’t share them.
In that sense, hardcore atheism and agnosticism are as symptomatic of rigidity and narrow-mindedness as extreme religiosity, and highlight an inability to understand alternative Weltanschauungen or opposite systems of values.
However, the authors forget to consider an important possibility, which is that the relationship between IQ and religiosity could be caused by a third variable, namely personality.