Study Confirms a Negative Correlation Between Intelligence and Religiosity

By Rosa Rubicondior | 24 April 2023
Rosa Rubicondior Blog


Meta-analysis of 83 studies produces ‘very strong’ evidence for a negative relationship between intelligence and religiosity

Q. Why are so few scientists religious and why do so many fundamentalists have no understanding of science and poor critical thinking skills?

A. Because learning science and thinking are hard, but religion is easy and requires no analytical skill.

In 2013 a team led by Professor of psychology at Rochester University, Miron Zuckerman, reported finding a negative correlation between intelligence and religiosity from a meta-analysis of 63 studies.

In 2019, with more studies being conducted and because his findings have been challenges, Zuckerman and colleagues repeated the meta-analysis with a larger data set of studies. This larger study has confirmed the earlier finding. showing the correlation between intelligence and religiosity is between -0.20 and -0.23. The correlation tends to be stronger in

For non-statisticians, what is a meta-analysis?

A meta-analysis is a statistical method used to combine and analyze the results of multiple independent studies on a particular research question or topic. It involves systematically reviewing and selecting relevant studies, extracting data from those studies, and then using statistical techniques to synthesize the data into a single quantitative estimate or effect size.

Meta-analysis is often used in scientific research to address questions where multiple studies have been conducted on the same topic, but individual studies may have produced conflicting or inconclusive results. By combining the results of multiple studies, meta-analysis can provide a more robust and precise estimate of the true effect size of a particular intervention or relationship.

Meta-analyses are typically conducted using a pre-defined set of criteria for selecting studies, and a set of statistical procedures for combining and analyzing the data. The results of a meta-analysis can be presented in various ways, including as a summary effect size estimate with confidence intervals, as a forest plot that shows the results of individual studies along with the combined estimate, or as a subgroup analysis that examines whether the effect size varies across different subgroups of studies.

Meta-analysis has become increasingly popular in many fields of research, including psychology, medicine, and education, as a way to synthesize and integrate research findings and to draw more reliable and generalizable conclusions from multiple studies.

The new study found evidence that an analytic (as opposed to intuitive) thinking style was related to both increased intelligence and reduced religiosity. There was no evidence that this correlation is changing over time.

Professor Zuckerman told the online psychology magazine, PsyPost:

Religiosity is a pervasive phenomenon. Its influence can be felt in all spheres of life. However, a sizeable portion of the population defines itself as atheist. Why do some people decide not to be religious? I thought it was an important and fascinating question.

Collecting new data to ascertain the validity of previous findings is crucial for science anytime, but especially when the subject matter is socially relevant and emotionally fraught.

The evidence that there is a negative relation between intelligence and religiosity is very strong. But the effect size of the relation is small. This means that there are factors besides intelligence that explain why people are or are not religious. It also means that although more intelligent people tend to be less religious on the average, predicting religiosity from intelligence for individuals is fallible.

Although we present reasons for the negative relation, the empirical evidence for these explanations is not definitive.

The negative relation was established for western societies. We don’t know whether it generalizes to other populations, particularly those in the Far East.

The team’s findings were published in the journal Personality and Social Psychology Bulletin, sadly behind a paywall. However, their abstract is freely available.

Although the correlation is strong, a correlation of between -0.20 and -0.23 suggests there is more behind religiosity than intelligence and critical thinking skills alone. Social and peer pressures and cultural imperatives such as the assumption that not being religious is somehow ‘wrong’ or even unpatriotic/anti-social are likely to be factors. A display of religiosity, whether genuine or not, is believed in some cultures to indicate trustworthiness – hence the large followings of American televangelists, so religion can provide excuses for people who need excuses, especially when their target marks lack critical thinking skills.

This, of course, will vary greatly between cultures. In the UK, for example, where religion has been in free-fall since the mid-twentieth century, religiosity is more likely to be regarded as a mental illness than an indicator of trustworthiness, and many people would be reluctant to leave their children in the care of a priest, so religiosity tends to play little or no part in political debate. In the UK, politicians “don’t do God”.

Rosa Rubicondior (a pseudonym) is a retired data analyst, biologist, blogger, author and atheist.

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