For nearly a century, psychologists have studied the relationship between religious beliefs and intelligence. A recent review and meta-analysis of research from 1928 until the present time, found 63 studies investigating this topic. The results show that religiosity has a significant negative relationship with intelligence, suggesting that stronger religious beliefs are associated with lower intelligence. While this finding is not new, there are some interesting ideas about why this relationship exists.
First, the authors discuss the idea that atheists are nonconformists, and that more intelligent people are less likely to conform. As the authors state, “if more intelligent people are less likely to conform, they also may be less likely to accept a prevailing religious dogma.”
The second possible explanation is that more intelligent persons rely more logical reasoning and empirical evidence in their belief systems. It might not be intelligence per se that leads to a lack of religious beliefs, but a cognitive style that is more critical of the prevailing religious beliefs in a community.