Religious people are less intelligent than non-believers, according to a new review of 63 scientific studies stretching back over decades.
A team led by Miron Zuckerman of the University of Rochester found “a reliable negative relation between intelligence and religiosity” in 53 out of 63 studies
Even in extreme old age, intelligent people are less likely to believe, the researchers found - and the reasons why people with high IQs shun religion may not be as simple as previously thought.
Previous studies have tended to assume that intelligent people simply “know better”, the researchers write - but the reasons may be more complex.
For instance, intelligent people are more likely to be married, and more likely to be successful in life - and this may mean they “need” religion less.
The studies used in Zuckerman's paper included a life-long analysis of the beliefs of a group of 1,500 gifted children - those with IQs over 135 - in a study which began in 1921 and continues today.
Even at 75 to 91 years of age, the children from Lewis Terman’s study scored lower for religiosity than the general population - contrary to the widely held belief that people turn to God as they age. The researchers noted that data was lacking about religious attitudes in old age and say, “Additional research is needed to resolve this issue.”
As early as 1958, Michael Argyle concluded, “Although intelligent children grasp religious concepts earlier, they are also the first to doubt the truth of religion, and intelligent students are much less likely to accept orthodox beliefs, and rather less likely to have pro-religious attitudes.”
A 1916 study quoted in Zuckerman’s paper (Leuba) found that, “58% of randomly selected scientists in the United States expressed disbelief in, or doubt regarding the existence of God; this proportion rose to nearly 70% for the most eminent scientists.”
The paper, published in the academic journal Personality and Social Psychology Review, said “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 who “know better.”
The answer may, however, be more complex. Intelligent people may simply be able to provide themselves with the psychological benefits offered by religion - such as “self-regulation and self-enhancement”, because they are more likely to be successful, and have stable lives.
“Intelligent people typically spend more time in school—a form of self-regulation that may yield long-term benefits,” the researchers write. “More intelligent people get higher level jobs (and better employment (and higher salary) may lead to higher self-esteem, and encourage personal control beliefs.”
“Last, more intelligent people are more likely to get and stay married (greater attachment), though for intelligent people, that too comes later in life. We therefore suggest that as intelligent people move from young adulthood to adulthood and then to middle age, the benefits of intelligence may continue to accrue.”
The researchers suggest that further research on the “function” of religion may reveal more..
“People possessing the functions that religion provides are likely to adopt atheism, people lacking these very functions (e.g., the poor, the helpless) are likely to adopt theism,” the researchers wrote.