(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).