Do elderly religious people in South Korea have lower mean IQ than elderly non-religious people?

Meta-analyses have found a negative relationship between religiousness and IQ of around r = −0.2, including in samples of elderly Westerners. However, there have been few attempts to directly test the existence of the religion-IQ nexus in non-Western societies. We administered a cognitive test to a representative sample of elderly South Koreans who were also surveyed about their religion and tested whether elderly nonreligious people had higher mean IQ scores than elderly religious people. Using a broad cognitive test battery, we computed mean IQ scores of n = 589 non-religious, n = 494 Protestants, n = 520 Catholics, n = 347 Buddhists, and n = 17 Confucianists. Elderly South Koreans who claimed to have 'no religion' had lower mean IQs than religious Koreans. This finding is not consistent with previous findings from meta-analyses. We argue that it is explicable in terms of differences in how the concept of religion is understood when comparing Western and Northeast Asian societies. Many of the 'non-religious' category would be adherents to Korean folk religion, something expected to be associated with lower mean IQ. • There is a negative relationship between religiousness and IQ. • The relationship has not been tested in non-Western societies. • We tested a representative sample of elderly South Koreans. • Elderly non-religious persons had lower mean IQs than elderly religious persons. • The non-religious are most likely adherents to Korean folk religion. [ABSTRACT FROM AUTHOR]