Intelligence moderates how education mediates the effect of social background on own attained occupational position

A positive cognitive ability × motivation interaction effect on performance has been suggested. In the area of working life, attained occupational position could be seen as a measure of performance and earlier studies have indicated that the commonly found association between social background and own attained occupational position might be mediated through attained level of education. In the present study, it is hypothesized that both social background and level of education might be indicative of educational/occupational motivation and, therefore, the importance of level of education as a mediator should increase with increasing intelligence. This hypothesis was confirmed in a cohort of Swedish men born in 1949–1951 (N = 49,246). This moderated mediation seems mainly to be due to a strengthening of the association between attained level of education and attained occupational position with increasing intelligence. The association between attained level of education and attained occupational position was found to be more linear among men with high intelligence scores and more exponential among men with low scores. It is discussed that this might be due to a low validity in the measurement of intelligence among men who receive a low intelligence score at conscription but who, nonetheless, go on and attain a high level of education.