A new meta-analysis looking at studies from 1921-2012 has concluded that non-religious people are likely to be more intelligent than religious people.
The analysis was performed by psychologists Miron Zuckerman and Jordan Silberman of the University of Rochester and Judith Hall of Northeastern University. Their findings were published in the Personality and Social Psychology Review.
The analysis was performed on 63 studies. Out of the 63 studies, 53 of them found “a reliable negative correlation between intelligence and religiosity.” The analysis produced interesting findings regarding people of all age levels.
According to the analysis, the more intelligent a child is, the more likely it would be turn away from religion. Likewise, people in old age of above average intelligence are less likely to be religious than those of lower intelligence levels.
One study analyzed was a lifelong study of 1,500 children with IQ’s above 135. The study, called the Terman cohort of the gifted, is still being conducted today. The study began in 1921, when Stanford psychologist Lewis Terman recruited 1,500 children whose IQ’s exceeded 135 by the age of ten. Despite the fact that 60% of the participant report receiving “very strict” or “considerable” religious instruction as children, the subjects display much lower levels of religious belief than the average population.
Out of the 63 studies analyzed, 53 showed a negative correlation between intelligence and religiosity, while 10 showed a positive one. Only two of the studies showed a significant positive correlation between intelligence and religiosity, while 35 of the studies displayed a significant negative correlation.
As is typical with a meta-analysis, the authors examined each study being analyzed independently and accounted for the quality of data collection, the size of the sample, and the analysis methods used in each study.
Religiosity was defined by the authors of the analysis as involvement in some, or all, facets of religion. Intelligence was defined as “the ability to reason, plan, solve problems, think abstractly, comprehend complex ideas, learn quickly, and learn from experience.”
Interestingly, the study found that factors such as gender and education did not affect the correlation to between intelligence and religious beliefs.
You can read the abstract section of the study here. In their conclusion, the psychologists offer several explanations for their findings. The authors summed up one commonly seen theme as follows:
"Most extant explanations (of a negative relation) share one central theme —the premise that religious beliefs are irrational, not anchored in science, not testable and, therefore, unappealing to intelligent people…”