To investigate the relationship between intelligence and religious belief between nations we have taken the IQs of nations given in Lynn and Vanhanen’s (2006) IQ and Global Inequality. This source shows that these national IQs have high reliability, as shown by the correlation of .92 between different measures, and high validity, as shown by the correlation of .83 between the IQs and educational attainment. The high reliability and validity of these national IQs has been confirmed by Rindermann (2007). We have taken figures for belief in God from Zuckerman (2007) who gives data for 137 countries representing just over 95% of the world’s population. These data were collected from surveys mostly carried out in 2004, although in a few countries the surveys were a year or two earlier. Zuckerman collated these data from a number of different surveys in order to provide results that were as up-to-date as possible. Where he published more than one survey result for a given country we took the most recent one where this was indicated, but averaged them out where it was not. Zuckerman’s figures consist of the percentages saying that they disbelieved in god, rather than the more frequent question asking for belief in god. Zuckerman draws attention to four problems associated with this data set. These are possible low response rates, weaknesses in random sample selection, regime or peer pressure influencing responses and problems of terminological variation between cultures over words such as ‘religious’ or ‘secular’. Despite these possible sources of error however Zuckerman urges acceptance of the data by quoting Robert Putnam to the effect that “we must make do with the imperfect evidence that we can find, not merely lament its deficiencies.”
The data for the national IQs and percentages asserting disbelief in god for the 137 countries are given in the appendix. It will be seen that in only 17% of the countries (23 out of 137) does the proportion of the population who disbelieve in god rise above 20%. These are virtually all the higher IQ countries.
The correlations between the national IQs and religious disbelief are given in Table 3. Row 1 gives the correlation of 0.60 for the total sample and is highly statistically significant (p<.001). To examine whether this relationship holds across the whole range of national IQs we have divided the nations into two groups of those with IQs between 64-86 and those with IQs between 87-108. Row 2 gives the data for the 69 countries with IQs between 64-86. In this group only 1.95 per cent of the population are non-believers. There is a range between <1% and 40%, and the correlation between the two variables is only 0.16. Row 3 gives the data for the 68 countries with IQs between 87-108. In this group 19.99 % per cent of the population disbelieve in god. There is a range between <1% and 81%, and the correlation between the two variables is only 0.54 (p<.001). Thus, most of the variation in religious disbelief is among the higher IQ nations.
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The results raise four points of interest. First, the hypothesis with which we began this study was that there is a negative correlation between IQ and religious belief. We have reviewed considerable evidence for this negative relationship among individuals in the United States and Europe and have added a new data set confirming this. Second, we have shown that the negative relationship between intelligence and religious belief is a difference in Psychometric g. Third, we have extended