...
http://emilkirkegaard.dk/en/wp-content/uploads/The-Relation-Between-Intelligence-and-Religiosity-A-Meta-Analysis-and-Some-Proposed-Explanations.pdf
Abstract
A meta-analysis of 63 studies showed a significant negative association between intelligence and religiosity. The association was stronger for college students and the general population than for participants younger than college age; it was also stronger for religious beliefs than religious behavior. For college students and the general population, means of weighted and unweighted correlations between intelligence and the strength of religious beliefs ranged from −.20 to −.25 (mean r = −.24).
Three possible interpretations were discussed. First, intelligent people are less likely to conform and, thus, are more likely to resist religious dogma. Second, intelligent people tend to adopt an analytic (as opposed to intuitive) thinking style, which has been shown to undermine religious beliefs. Third, several functions of religiosity, including compensatory control, self-regulation, self-enhancement, and secure attachment, are also conferred by intelligence. Intelligent people may therefore have less need for religious beliefs and practices.
and a paragraph on Limitations:
Limitations
The available data did not allow adequate consideration of the role of religion type and of culture. As mentioned herein before, the articles included in the meta-analysis did not provide enough information to code religion type as a potential moderator. There was also not enough information to consider the role of culture in the intelligence–religiosity association. Of the 41 studies in the college and no-college groups (the populations on which we base most of our conclusions), 33 were conducted in the United States; the remainder were conducted in Canada (3), Australia (2), Belgium and Holland (1 each); finally, one study was conducted in several countries but primarily (87% of participants) in the United States, Canada, and the United Kingdom. Clearly, the present results are limited to Western societies.
Worth repeating:
...showed a significant negative association between intelligence and religiosity.
= new reply since forum marked as read