Does Religiosity Affect Intelligence?

Many recent studies have been done testing if religiosity is linked to lower intelligence. I find this topic very interesting, because I have never thought that being religious could affect intelligence. If anything, I would have thought that religious people are more intelligent, just because of personal experience with very religious people.

One correlational study looked at atheists and religious people. In a sample of 27 undergraduate students, they found a strong correlation between higher IQ and atheism. In IQ tests, they found that atheists scored on average 3.82 IQ points above people who were slightly religious, and 5.89 points above very religious people. They tested the religiosity of people through questionnaires. More studies have been done to improve the findings and build on what they learned. Since it’s a correlation, there is a possibility of other variables. Religious people take a lot of time out of their lives to pray and go to church. This is time they could be using to learn things, improve their memory, or do schoolwork. So, this could explain why they did worse in IQ tests.

Another study of 2307 (1035 men, 1262 women, and 10 “individuals”) participants was conducted. All people who weren’t Christian were excluded from the study, except for people who are atheist (3.2%) or had no religious preference (11.4%). Using a Likert scale, they collected data on six religious measures: mindfulness, spirituality, religious support, religious identification, private religious practice, and fundamentalism. According to Wikipedia, a Likert Scale is a “psychometric scale” that employs questionnaires to collect data. The data collected is shown in the table below:

Measure Mean SD
Mindfulness 34.02 6.10
Spirituality 6.41 1.56
Religious support 18.51 3.83
Religious identification 19.45 5.61
Private religious practice 9.64 4.28
Fundamentalism 4.89 2.11
Measure Mind Spirit Supp Id Priv Fund IQ Edu O Age
Spirit .51
Supp .50 .65
Id .39 .60 .67
Priv .46 .64 .70 .69
Fund .23 .31 .39 .52 .42
IQ −.09 −.05 −.10 −.14 −.15 −.25
Edu −.04 −.03 −.05 −.09 −.06⁎⁎ −.34 .41
O .23 .13 .06⁎⁎ −.03 .01 −.12 .13 .20
Age .08 .04 .11 .14 .18 .10 −.45 −.15 −.02
Sex .15 .16 .17 .13 .18 .05* −.03 −.10 −.02 −.04

To test intelligence, they conducted 5 sub-tests. Each test had a category: “word list recall, working memory span, verbal fluency, inductive reasoning, and speed of processing.” After analyzing data, and comparing the participant’s scores with their intelligence score, they concluded that intelligence was negatively associated with 5/6 of the religion categories that they tested. Fundamentalism was the only category that positively associated religion with intelligence.

This study would be more persuading if they took the time to measure people and their intelligence from a young age. They could monitor people who are raised as atheists and people who are raised in very religious families, and test their intelligence as they grow. I think they also need to make sure that the people who identify as religious have chosen to be religious, and are not being forced by their family or people around them. I can see why they would exclude other religions to keep the data constant, but I’m curious if other religions have the same effect on people as well. Reverse causation could also be a factor in these correlational studies. It’s possible that people who are more intelligent decide not to be religious. This website says that intelligent people could believe that religion is “irrational and unscientific,” which could explain why intelligent people tend to be atheists.

When I think about my personal experiences, I find that people who are religious are very smart. For example, the people who were at the top of my class in high school were very religious and had very good memories (which is one of the intelligence categories measured in the study above).

In a meta-analysis that was conducted, 63 studies were analyzed. Of the 63 studies, 53 of them had a negative correlation between religiosity and how smart a person is. The other 10 had a positive correlation. So, 84% of the studies showed that nonreligious people were more intelligent. Richard Lynn also did a study comparing national IQ’s of countries and how religious they are. The results are shown in the graph below. The graph shows that countries had higher IQ’s as the percentage of atheists increased. But as you can see, countries with less atheists could also have high IQs.


Overall, many studies I came across concluded that religiosity is negatively correlated with intelligence. So, it’s hard to argue with the data. But, this doesn’t mean that people should stop being religious just to be smarter. The findings showed that it didn’t have a very big effect on intelligence, so why should people give up something they enjoy and believe in just to be slightly smarter?

2 thoughts on “Does Religiosity Affect Intelligence?

  1. Michael Bliss

    This is a very great blog, and I never would have guessed that there was a correlation between these two traits. As we learned in class, the most shocking results causes more research to be done, and I think that should be the case here too. If this link is legitimate, which trait would cause the other? Does religion cause people to be less intelligent, or does being less intelligent cause people to become more religious? Discovering the causation and mechanism of this link would be very difficult to find, but very interesting.

  2. pxw5127

    I found this blog to be super interesting, probably the most interesting blog I have read thus far. I would never have guessed that intelligence would be negatively correlated with religiosity, but I guess I was mistaken. I think that some of these findings could definitely be due to chance. I think you correctly identified third variable such as the age when they start analyzing intelligence. I think that age could definitely affect these results, as well as time spent practicing the religion. People who are very religious devote much of their time to their religion, and not as much to reading and researching. I also think that maybe atheists could choose to be atheists because they are so smart, they choose to analyze every little thing about a religion, and find their own reasoning to why it is not real, or find small things that could be wrong with it. You said it right, “this doesn’t mean that people should stop being religious just to be smarter.” This would just be absurd if someone thought that they would become smarter if they stopped practicing their religion. This Website ,which was one you used, stated, ” sex or education made no difference in the correlation between intelligence and religiosity.” So maybe this argument is valid, and maybe it is true, but researchers still have a lot more work to do.

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