I'm sure we can all figure out the religious poster who couldn't follow abstract thinking, perform thought experiments or use analogy, and was often criticized for being 'dumb'!
Out of 63 studies, 53 showed a negative correlation between intelligence and religiosity, while 10 showed a positive one. Significant negative correlations were seen in 35 studies, whereas only two studies showed significant positive correlations.
The three psychologists have defined intelligence as the "ability to reason, plan, solve problems, think abstractly, comprehend complex ideas, learn quickly, and learn from experience". In the various studies being examined, analytic intelligence has been measured in many different ways, including GPA (grade point average), UEE (university entrance exams), Mensa membership, and Intelligence Quotient (IQ) tests among others.
Religiosity is defined as involvement in some (or all) facets of religion, which includes belief in the supernatural, offering gifts to this supernatural, and performing rituals affirming their beliefs. Other signs of religiosity were measured using surveys, church attendance, and membership of religious organizations.
The article gives reasons why intelligent people tend to be more religious, but I believe the stupidity I've witnessed is from a 'dumbing effect' caused by religious fanaticism.
http://www.dailynewscrunch.com/news/sci ... and-faith/