The interrelations of marital status,fertility, family size and intelligence test scores

In this paper data relating to men born in 1924 in the two southernmost counties of Sweden, and called up for military service in 1944 are analyzed. The population registers yield certain demographic and social information about these men, and this may be related to their performance in an intelligence test administered when they were called up. The association between test scores and level of schooling on one hand, and such variables as nuptiality, age at marriage, number of sibs, marital fertility, the incidence of pre-nuptial conceptions and occupational class is discussed, and an estimate of the influence of differential fertility on the trend of intelligence is given.