Are religious people less intelligent?

By December 5, 2017Science, Society

When scientists say they have undertaken a meta-analysis1, it means that they have looked at the raw data from several other studies and extracted what is required from it to test an hypothesis. The ‘basic tenet’ behind meta-analysis is that there is a common truth behind all conceptually similar scientific studies. The use of statistics can tease out this common truth.

A recent paper by Zuckerman et al. (2013)2 undertook a meta-analysis of 63 studies examining the association between intelligence and religiosity. This has been examined in numerous studies, and Zuckerman et al. list many, some from as long ago as 1928. Of these, several analyses indicated there was little difference, except for one study which showed that fundamentalists score a little lower. These studies were mostly in the second half of the 20th century, but in a flurry of activity at the beginning of this century, a negative correlation between intelligence and religiosity was indicated.

In parallel to the studies above, psychologists also studied the prevalence of religiosity among scientists and all studies have indicated that scientists are less likely to be religious than the general populace. Zuckerman et al. came to the conclusion that there was no clear consensus as to any correlation between intelligence and religiosity. Furthermore, there was no consensus on what could explain any correlation.

Zuckerman et al. examined this supposed relationship using a tripartite subdivision into: school students, adolescent university students and adolescent non-students. In addition, they attempted to examine explanations for any relationship between intelligence and religiosity.

Zuckerman et al. took account of the following: gender; which intelligence test was used; how religiosity was measured; the aim of the original study used in the meta-analysis; sample type; religious sect; and race; and undertook an analysis of bias in the original studies.

Their results demonstrated a reliable negative relationship between intelligence and religiosity, and that this was weaker (-0.08) in school students than in university or non-university adolescents (-0.20 to -0.25). Three interpretations to explain this correlation were put forward. These were:

  1. Intelligent people are generally more analytical and data driven, the antithesis of religion.
  2. Intelligent people are less likely to conform, and in most societies, religiosity is closer to the norm than atheism.
  3. Intelligence and religiosity both allow the individual to exercise better self-control and that intelligence leads to lower religiosity because it effectively replaces the self-control function of religion.

However, the cause was unable to be determined based on the data available.

One other item of interest was something mentioned by Tomas Chamorro-Premuzic in ‘Psychology Today’3. He suggested that Zuckerman et al. did not consider an important possibility; that the relationship between intelligence and religiosity could be caused by a third variable, namely personality. He suggested that ‘openness to experience’, which predicts an individual’s higher levels of intellectual curiosity, aesthetic sensitivity, all driven by nonconformity, is positively correlated with intelligence, and, like intelligence, is stable from an early age. Furthermore, there is also ample evidence suggesting that greater openness may cause a gain in intelligence in adulthood because open individuals are more likely to invest time and resources acquiring expertise and knowledge.

So, it seems that there is a negative correlation between intelligence and religiosity, but it may be mediated by the type of personality a person has.

From my experience, the most important thing you can do with your life is to broaden your horizons. If you are a chemist, read books on geology, cosmology, history, economics, archaeology, poetry, musicology, art, etc. You will be rewarded, not least by the ability to kick off the shackles of religion.


  2. Zuckerman, M., Silberman, J & Hall, J.A., 2013. The relation between intelligence and religiosity: a meta-analysis and some proposed explanations. Personality and Social Psychology Review 17(4), 325-354.

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