As I noted, there is a discussion regarding if atheists are smarter than people from other religions. From the NLY97 I have now included how people with different religions score on aptitude tests, often used by researchers as a proxy for I.Q.
(Of course these are just test score, neither I nor anyone else can guarantee that they are not biased for any religion. Take them for what they are worth.)
It is well known that Jewish people score very high in I.Q tests. What is less well known is that Episcopalians also get astronomical I.Q scors.
Note again that new age types with "personal philosophies" rather than pure atheism are not smarter than average.
The most important thing I note is that Mormons are smarter than average. If you are going to go around saying that atheists are smarter than average, you should know that the same tests show Mormons to be smarter than average as well.
Mormonism is not just a religion. It is a cohesive and self-replicating cultural identity, with strong positive effects on behavior and outcome for its members.