Their research tells us there is a negative relationship in the U.S. and Europe, and in a sample of 137 countries the correlation between national IQ and disbelief in God is significant.
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 and the 1950s by researchers who concluded that "intelligent students are much less likely to accept orthodox beliefs, and rather less likely to have pro-religious attitudes". Evidence comes from four sources:
(1) Negative correlations between intelligence and religious belief.
A recent review of the research literature looked at 43 studies, of which all but four found a negative correlation. In a more recent study in the United States, kids 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 average IQ (103.09), followed in descending order by the other three groups (IQs = 99.34, 98.28, 97.14).
(2) Lower percentages holding religious beliefs among intelligence elites compared with the general population.
In the 1990s a study of members of the American National Academy of Sciences reported that 7% believed in the existence of God, as compared with approximately 90% found in a poll of the general population. In Britain, it has been reported that 3.3% of Fellows of the Royal Society believed in the existence of God, while 78.8% did not believe. At the same time a poll showed that 68.5% 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. Among 12 year olds 94% endorsed the statement "I believe there is a God", while among 18 year olds this had fallen to 78%. Similarly, in England, a decline in religious belief over the age range 5-16 years has been revealed.
(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 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, declined from 40% of the population in 1850, to 35% in 1900, to 20% in 1950, to 10% in 1990.
In the United States, students at Bryn Mawr were asked whether they believed in a God who answered prayers. Positive responses were given by 42% of students in 1894, 31% in 1933, and 19% in 1968. Students enrolling at the University of Michigan were invited to provide a "religious preference". In 1896, 86% of students did so; in 1930 this had dropped to 70%, and in 1968 it had dropped to 44%.
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.
The data for the national IQs and percentages asserting disbelief in god for the 137 countries show 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 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. 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. So 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.
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 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 proposed that "greater intellectual maturity might be expected to increase scepticism in matters of religion". Inglehart and Welzel 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".
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.
The United States is anomalous in having an unusually low percentage of its population disbelieving in God (10.5%) 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.
Further Reading
Argyle, M. (1958). Religious Behaviour. London: Routledge and Kegan Paul.
Argyle, M. and Beit-Hallahmi, B. (1975). The Social Psychology of Religion. London: Routledge and Kegan Paul.
Beit-Hallahmi, B. and Argyle, M. (1997). The Psychology of Religious
Belief and Experience, London, Routledge.
Bell, P. (2002). Would you believe it? Mensa Magazine, Feb., 12-13.
Dawkins, R. (2006). The God Delusion. London: Bantam Press.
Francis, L.J. (1989). Measuring attitudes towards Christianity during childhood and adolescence. Personality & Individual Differences, 10, 695-698.
Frazer, J. G. (1922). The Golden Bough. London: Macmillan.
Giddens, A. (1997). Sociology. Cambridge, UK: Polity Press.
Gilliland, A.R. (1940). The attitude of college students towards God and church. Journal of Social Psychology, 11, 11-18.
Goldman, R.J. (1965). Do we want our children taught about God? New Society, 27 May.
Heath, D.H. (1969). Secularization and maturity of religious belief. Journal of Religion and Health, 8, 335-358.
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.
Inglehart, R. and Welzel, C. (2005). Modernization, Cultural Change, and Democracy: The Human Development Sequence. Cambridge: Cambridge University Press, 2005).
Kanazawa, S. (2007). De gustibus est disputandum 11: why liberals and atheists are more intelligent. (Unpublished).
Kuhlen, R.G. & Arnold, M. (1944). Age differences in religious beliefs and problems during adolescence. Journal of Genetic Psychology, 65, 291-300.
Koenig, L.B., McGrue, M., Krueger, R.F. and Bouchard, T.J. (2005). Genetic and environmental influences on religiousness: Findings for retrospective and current religiousness ratings. Journal of Personality, 73, 471-488.
Larsen, E.L. and Witham, L. (1998). Leading scientists still reject God. Nature, 394, 313.
Leuba, J.A. (1921). The Belief in God and Immortality. Chicago: Open Court Publishers.
Newcomb, T.M. and Svehla, G. (1937). Intra-family relationships in attitude. Sociometry, 1, 180-205.
Rindermann, H. (2007). The g-factor of international cognitive ability comparisons: The homogeneity of results in PISA, TIMMS, PIRLS and IQ-tests across nations. European Journal of Personality, 21, 667-706.
Roe, A. (1965). The Psychology of Occupations. New York: Wiley.
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.
Turner, E.B. (1980). General cognitive ability and religious attitudes in two school systems. British Journal of Religious Education, 2, 136-141.
Verhage, F. (1964). Intelligence and religious persuasion. Nederlands tijdschrift voor de psychologie en haar grensgebieden, 19, 247-54.
Zuckerman, P. (2007). Atheism: Contemporary Numbers and Patterns. In M. Martin (Ed) The Cambridge Companion to Atheism. Cambridge: Cambridge University Press.