"Why should fewer academics believe in God than the general population? I believe it is simply a matter of the IQ. Academics have higher IQs than the general population," says Ulster University academic Richard Lynn. "Several Gallup poll studies of the general population have shown that those with higher IQs tend not to believe in God."

Hmmm. What are we to make of this? Professor Lynn and colleagues wrote a paper in 2008 in the journal Intelligence which has been widely discussed. Here is a summary of its claims:

Evidence is reviewed pointing to a negative relationship between intelligence and religious belief in the United States and Europe. It is shown that intelligence measured as psychometric g is negatively related to religious belief. We also examine whether this negative relationship between intelligence and religious belief is present between nations. We find that in a sample of 137 countries the correlation between national IQ and disbelief in God is 0.60 [a high correlation].

The highlight of the paper is the chart of 137 nations. And it looks pretty convincing until you study it carefully. Then, picturing the data is a cart for the theory, wheels start wobbling.

I first became suspicious when Lynn et al. tried to explain why the United States is anomalous “in having an unusually low percentage of its population disbelieving in God (10.5 percent) for a high IQ country [98].”

One factor that could provide a possible explanation for this is that many Americans are Catholics, and the percentage of believers in Catholic countries in Europe is generally much higher than in Protestant countries (e.g. Italy, 6 percent; Ireland, 5 percent; Poland, 3 percent; Portugal, 4 percent; Spain, 15 percent). Another possible contribution to this has been continued high immigration of those holding religious beliefs. A further possible factor might be that a number of emigrants from Europe went to the United States because of their strong religious beliefs, so it may be that these beliefs have been transmitted as a cultural and even genetic legacy to subsequent generations. Parent–child correlations for religious belief are quite high at 0.64 (fathers–sons) and 0.69 (mothers–daughters) (Newcomb & Svehla, 1937). It has been found that religious belief has a significant heritability of around 0.40–0.50 (Koenig, McGrue, Krueger & Bouchard, 2005), so it could be that a number of religious emigrants from Europe had the genetic disposition for religious belief and this has been transmitted to much of the present population.

Good thing it’s easy to test that oe. Canada has a similar history, and features average IQ 99, with 22 percent not believing in God. So twice as many Canadians don’t believe in God but exhibit no statistically significant reward in IQ. That’s one wheel off - but it’s still a tricycle.

Looking at the chart closely, I noticed another anomaly: The Czech Republic and Slovakia split on January 1, 1993. In 2008, the Czech republic clocked IQ 98, 61 percent disbelieving in God, and Slovakia at IQ 96, with only 17 percent disbelieving in God. The difference is obviously cultural. Second wheel gone. We now have a bicycle.

The third wobbly wheel was the fact that Israel and Portugal -with very different culture and histories - both feature IQ 95. But in Israel 15 percent disbelieve and in Portugal 4 percent. So tripling or quadrupling the number of atheists did nothing for IQ when culture and history are different. Will the data at least give us a unicycle for the theory to wobble on?

Perhaps. The reader may protest, after all, that these are individual cases. Very well, let’s be daring. Let’s drop from the list all nations where government either enforces or forbids religion or is known to be generally unrepresentative. Most such countries report lower average IQ. But the centralized thinking of authoritarian culture could well cause lower IQ.

So here’s the trimmed list, with countries listed by IQ - in alpha order when showings are equal. The only serious purpose of this list is to demonstrate that the case for “a negative relationship between intelligence and religious belief” is nonsense:

Countries by IQ and percent not believing in God

Note, for example, that four nations scored an even IQ 100. Arranged by level of atheism, they are:

In other words, the level of atheism could range from 18 percent up to 42 percent, with the average IQ at 100. Maybe it’s time to turn that unicycle into a plant stand. There is no consistent relationship between religion and IQ.

Next Monday: Religion rots teenagers’ intelligence too?

Denyse O'Leary is co-author of The Spiritual Brain.