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The Real Reason Atheists Have Higher IQs

Is atheism a sign of intelligence?

Recent posts have proposed convoluted theories accounting for why atheists score higher on IQ tests than religious people. There is a much simpler explanation. Like a lot of correlations of this type, it is probably less exciting than it appears.

Atheists are probably more intelligent than religious people because they benefit from many social conditions that happen to be correlated with loss of religious belief. When one looks at this phenomenon from the point of view of comparisons between countries, it is not hard to figure out possible reasons that more intelligent countries have more atheists as Richard Lynn (2009) reported.

Here are some. Highly religious countries (Barber, 2012):

  • Are poorer.
  • They are less urbanized.
  • Have lower levels of education.
  • They have less exposure to electronic media that increase intelligence (Barber, 2006).
  • Experience a heavier load of infectious diseases that impair brain function.
  • Suffer more from low birth weights.
  • Have worse child nutrition.
  • Do a poor job of controlling environmental pollutants such as lead that reduce IQ.

Given that each of these factors are recognized causes of low IQ scores (Barber 2005), there is little mystery about why religious countries score lower on IQ tests. Of course, the same phenomena are relevant to comparisons within a country, although within-country differences in these factors are generally smaller. Even so, the wealthier individuals in a country experience life differently than the poorer ones, developing higher IQ scores and greater religious skepticism.

As to the more exciting explanations, I doubt that religion causes stupidity if only because some of the most brilliant people of history, such as Isaac Newton, were highly religious like most of their contemporaries.

Whether intelligence causes people to reject religious belief is more complex. It is certainly plausible that highly intelligent people would have a problem accepting some of the more improbable beliefs required by their church Moreover, modern science offers explanations for phenomena that were previously explained in terms of religion and intelligent people may prefer the scientific account..

In short, discussing correlations between IQ and religiosity without a grasp of the relevant underlying factors is something of a parlor game. It recalls the long and tiresome debate about the correlation between IQ scores and skin color that got a lot of people very excited but proved a scientific dead end.

The really interesting question buried in all of this is why atheism is sparked uniquely by contemporary conditions in developed countries. I will return to this in a future post


Barber, N. (2005). Educational and ecological correlates of IQ: A cross-national investigation. Intelligence, 33, 273-284.
Barber, N. (2006). Is the effect of national wealth on academic achievement mediated by mass media and computers? Cross-Cultural Research, 40, 130-151.

Barber, N. (2012). Why atheism will replace religion: The triumph of earthly pleasures over pie in the sky. E-book, available at:

Lynn, R., Harvey, J., & Nyborg, H. (2009). Intelligence predicts atheism across 137 nations. Intelligence, 37, 11-15.