The relationship between date of birth and individual differences in personality and general intelligence: A large-scale study

We investigated the relationship between date of birth and individual differences in personality and intelligence in two large samples. The first sample consisted of 4000+ middle-aged male subjects from the Vietnam Experience Study; personality was measured by the MMPI items converted to EPQ (scales) and a large battery of cognitive tests were factored to derive general intelligence, g. The second sample consisted of 11,000+ young adults from the National Longitudinal Study of Youth from 1979. g was extracted from the ten subtests of the Armed Services Vocational Aptitude Battery. In no cases did date of birth relate to individual differences in personality or general intelligence. A further goal was to test Eysenck’s notion of possible relationships between date of birth and the popular Sun Signs in astrology. No support could be found for such associations. We conclude that the present large-scale study provides no evidence for the existence of relevant relationships between date of birth and individual differences in personality and general intelligence.