Intelligence (to appear)

Average Intelligence Predicts Atheism Rates across 137 Nations

Richard Lynna* ,  John Harveyb, Helmuth Nyborgc

aUniversity of Ulster, Coleraine, Northern Ireland, b1 Drove Cottages, Rodmell, Lewes, East Sussex BN7 3HD, England, cUniversity of Aarhus, Denmark (1968-2007)

*Corresponding author. E-mail address: Lynnr540@aol.com

Keywords: Religion; IQ

Abstract

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.

1. Introduction

Dawkins’ (2006) recent book The God Delusion suggests that it is not intelligent to believe in the existence of God. In this paper we examine (1) the evidence for this contention, i.e. for whether there is a negative relationship between intelligence and religious belief; (2) whether the negative relationship between intelligence and religious belief is a difference in psychometric g; and (3) whether there is negative relationship between intelligence and religious belief between nations.

2.Intelligence and Religious Belief within Nations

We are by no means the first to suggest the existence of a negative relationship between intelligence and religious belief within nations. This phenomenon was observed in the 1920s by Howells (1928) and Sinclair (1928), who both reported studies showing negative correlations between intelligence and religious belief among college students of -.27, and -.29 to -.36 (using different measures of religious belief). In the 1950s Argyle (1958) concluded that “intelligent students are much less likely to accept orthodox beliefs, and rather less likely to have pro-religious attitudes”.

Evidence pointing to a negative relationship between intelligence and religious belief within nations comes from four sources. These are (1) negative correlations between intelligence and religious belief; (2) lower percentages holding religious beliefs among intelligence elites compared with the general population: (3) a decline of religious belief with age among children and adolescents as their cognitive abilities increase; (4) a decline of religious belief during the course of the twentieth century as the intelligence of populations has increased.

(1) Negative correlations between intelligence and religious belief.

A number of studies find negative correlations between intelligence and religious belief. A review of these carried out by Bell (2002) found 43 studies, of which all but four found a negative correlation. To these can be added a study in the Netherlands of a nationally representative sample (total N = 1538) that reported that agnostics scored 4 IQs higher than believers (Verhage, 1964). In a more recent study Kanazawa (2007) has analysed the data of the American National Longitudinal Study of Adolescent Health, a national sample initially tested for intelligence with the PPVT (Peabody Picture Vocabulary Test) as adolescents and interviewed as young adults in 2001-2 (N= 14,277).  At this interview they were asked: “To what extent are you a religious person?” The responses were coded “not religious at all”, “slightly religious”, “moderately religious”, and “very religious”. The results showed that the “not religious at all” group had the highest IQ (103.09), followed in descending order by the other three groups (IQs = 99.34, 98.28, 97.14). The relationship between IQ and religious belief is highly significant (F (3, 14273) = 78.0381, p < .00001).

(2) Lower percentages holding religious beliefs among intelligence elites compared with the general population.

In corroboration of these studies finding negative correlations between intelligence and religious belief is evidence comparing the percentages of religious believers among intelligence elites compared with the general population. This was shown as early as 1921 in a survey of the religious beliefs of eminent American scientists and scholars that reported that 39 per cent stated that they believed in God (with a range of 48 per cent among historians to 24 per cent among psychologists) (Leuba, 1921). It was reported by Roe (1965) that among a group of 64 eminent scientists, 61 were “indifferent to religion”, leaving approximately 4.8 per cent as religious believers. These are much lower than the percentage religious believers in the population among whom 95.5 per cent in the United States stated that they believed in God in a 1948 Gallup Poll (Argyle, 1958). In the 1990s a study of members of the American National Academy of Sciences reported that 7 per cent believed in the existence of God, as compared with approximately 90 per cent found in a poll of the general population (Larsen and Witham, 1998). In Britain, it has been reported that 3.3 per cent of Fellows of the Royal Society believed in the existence of God, while 78.8 per cent did not believe (the remainder being undecided) (Dawkins, 2006). At the same time a poll showed that 68.5 per cent of the general population believed in the existence of God.

(3) Decline of religious belief with age among children and adolescents

Also consistent with the negative correlation between intelligence and religious belief is the decline in religious belief during adolescence and into adulthood as cognitive ability increases. This has been found in the United States for the age range of 12-18 year olds by Kuhlen and Arnold (1944) who reported that among 12 year olds 94 per cent endorsed the statement “I believe there is a God”, while among 18 year olds this had fallen to 78 per cent. Similarly, in England Francis (1989) has found a decline in religious belief over the age range 5-16 years. Religious belief was measured by a scale consisting of questions like “God means a lot to me” and “I think that people who pray are stupid”, etc., and the scores on the scale are shown in abbreviated form in Table 1. The finding that girls score higher than boys has frequently been found (see e.g. Argyle, 1958).  In another study, among 12-15 year olds at a Protestant school in Northern Ireland, favourable attitudes to religion fell steadily and significantly (p<.001) with each year of age by approximately 0.75 of a standard deviation over the 4 year period, while the correlations between a favourable attitude to religion and IQ turned increasingly and significantly negative (p<.001) (Turner, 1980). These results are summarized in Table 2. (These trends were less clear for a Roman Catholic school). 

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(4) Decline of religious belief during the course of the twentieth century as the intelligence of the population has increased.

There is evidence for a decline of religious belief during the course of the last 150 or so years, while at the same time the intelligence of the population has increased. The increase in intelligence is a well-documented phenomenon that has become known as the Flynn effect. The decline of religious belief has been shown by statistics for church attendance and for belief in God recorded in opinion polls. For instance, in England self reported weekly attendance at church services in census returns (these numbers may be exaggerated) declined from 40 per cent of the population in 1850, to 35 per cent in 1900, to 20 per cent in 1950, to 10 per cent in 1990 (Giddens, 1997, p.460); Church of England Easter week communicants declined from 9 per cent of the population in 1900 to 5 per cent in 1970 (Argyle and Beit-Hallahmi, 1975); the attendance of children at Sunday schools declined from 30 per cent of the child population in 1900 to 13 per cent in 1960 (Goldman, 1965). In Gallup Polls 72 per cent of the population stated in 1950 that they believed in God (Argyle, 1958), but by 2004 this had fallen to 58.5 per cent (Zuckerman, 2006).

There has also been some decline of religious belief during the course of the last century in the United States. Hoge (1974) has reviewed several surveys that have found a decline of religious belief in college students. For instance, students at Bryn Mawr were asked whether they believed in a God who answered prayers. Positive responses were given by 42 per cent of students in 1894, 31 per cent in 1933, and 19 per cent in 1968. Students enrolling at the University of Michigan were invited to provide a “religious preference”. In 1896, 86 per cent of students did so; in 1930 this had dropped to 70 per cent, and in 1968 it had dropped to 44 per cent. At Harvard, Radcliffe, Williams and Los Angles City College the percentages of students who believed in God, prayed daily or fairly frequently, and attended church about once a week all declined from 1946 to 1966. Heath (1969) has also reported a decline in belief in God among college students from 79 per cent in 1948 to 58 per cent in 1968 Among the general population, Gallup Polls have found that 95.5 per cent stated that they believed in God in 1948 (Argyle, 1958), but by 2004 this had fallen to 89.5 per cent (Zuckerman, 2006).

3. Religious Belief and Psychometric g

   To determine whether there is negative relation between religious belief and Psychometric g (the general factor in intelligence), the data from the National Longitudinal Study of Youth (NLSY97) have been analysed. The NLSY97 is a national sample selected to represent approximately 15 million American adolescents in the age range of 12-17 years in 1997. The subjects (N= 6,825) were asked about current religious preferences in addition and took the Computer Adaptive form of the Armed Services Vocational Aptitude Battery (CAT-ASVAB97). This test consists of twelve scales (10 power and 2 speeded). These were analysed in terms of Raschian probabilistic modelling and the resulting one-dimensional scale correlated .992 (Psychometric R) with general intelligence, g, (Principal Axis Factor Analysis (t(N-2) = 662.62; p < .000). Atheists scored 6 g-IQ equivalent points higher than the combined group of subjects professing to one or another of a large number of different religions. The difference in general intelligence among atheists and believers was significant even without using weighted data (t(1, 6.893) = 2.87; p = .004).

4. Intelligence and Religious Belief between Nations

   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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5. Discussion

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 this hypothesis to an examination of whether a negative correlation between IQ and religious belief is present between countries. Using data from 137 countries we found a correlation of 0.60 between national IQs and disbelief in god. Although the measure used for the analysis across nations was for disbelief in god rather than for belief in god, we believe it can be reasonably assumed that disbelief in god is highly (negatively) correlated with belief in god. Hence, we conclude that the negative correlation between IQ and religious belief that has been found in numerous studies within nations is also present between nations.

Second, this conclusion raises the question of why should there be this negative correlation between IQ and belief in god. Many rationalists no doubt accept the argument advanced by Frazer (1922, p.712) in The Golden Bough that as civilisations developed “the keener minds came to reject the religious theory of nature as inadequate … religion, regarded as an explanation of nature, is replaced by science” (by “keener minds” Frazer presumably meant the more intelligent). Others have assumed implicitly or explicitly that more intelligent people are more prone to question irrational or unprovable religious dogmas. For instance, some sixty years ago Kuhlen and Arnold (1944) proposed that “greater intellectual maturity might be expected to increase scepticism in matters of religion”. Inglehart and Welzel (2005, p.27) suggest that in the pre-industrial world, humans have little control over nature, so "they seek to compensate their lack of physical control by appealing to the metaphysical powers that seem to control the world: worship is seen as a way to influence one's fate, and it is easier to accept one's helplessness if one knows the outcome is in the hands of an omnipotent being whose benevolence can be won by following rigid and predictable rules of contact…one reason for the decline in traditional religious beliefs in industrial societies is that an increasing sense of technological control over nature diminishes the need for reliance on supernatural powers". 

Third, there are a few exceptions to the generally linear relationship between IQ and disbelief in god across nations. Two of the most anomalous are Cuba and Vietnam, which have higher percentages disbelieving in god (40% and 81%, respectively) than would be expected from their IQs of 85 and 94 (respectively). This is likely attributable to these being former or current communist countries in which there has been strong atheistic propaganda against religious belief. In addition, it has sometimes been suggested that communism is itself a form of religion in which Das Capital is the sacred text, Lenin was the Messiah who came to bring heaven on earth, while Stalin, Mao, Castro and others have been his disciples who have came to spread the message in various countries. On these grounds, it may be argued that many of the peoples of Cuba and Vietnam hold a variant of more conventional religious belief in god.

              Fourth, the United States is anomalous in having an unusually low percentage of its population disbelieving in God (10.5 per cent) for a high IQ country. The percentage disbelieving in God in the United States is much lower than in north west and central Europe (e.g. Belgium, 43%; Netherlands, 42%; Denmark, 48%; France, 44%; UK, 41.5%). 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%; Ireland, 5%; Poland, 3%; Portugal, 4%; Spain, 15%). 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 and Svehla, 1937). It has been found that religious belief has a significant heritability of around 0.40 – 0.50 (Koenig, McGrue, Krueger and 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.

References

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Hoge, D.R. (1974). Commitment on Campus: Changes in Religion and Values over Five Decades. Philadelphia: Westminster Press.

Howells, T.H. (1928). A comparative study of those who accept as against those who reject religious authority. University of Iowa Studies of Character, 2, No.3.

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Kuhlen, R.G. & Arnold, M. (1944). Age differences in religious beliefs and problems during adolescence. Journal of Genetic Psychology, 65, 291-300.

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Larsen, E.L. and Witham, L. (1998).  Leading scientists still reject God. Nature, 394, 313.

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Sinclair, R.D. (1928). A comparative study of those who report the experience of the divine presence with those who do not. University of Iowa Studies of Character, 2, No.3.

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Zuckerman, P. (2007). Atheism: Contemporary Numbers and Patterns. In M. Martin (Ed) The Cambridge Companion to Atheism.  Cambridge: Cambridge University Press.

Table 1. Decline in percentage holding religious belief, with age (Francis,1989)

Table 2. Declining belief Correlates with Age (sd =15.6)(Turner,1980)

* significant at p<.01

Table 3. Correlations between the National IQs and Religious Disbelief

Appendix.

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