Changing Differences in Intelligence? Comparisons between groups of 13‐year‐olds tested from 1960 to 1990

Abstract

Abstract The purpose of the investigation is to study changes in verbal, spatial and reasoning intelligence among Swedish 13 year‐olds between 1960 and 1990. Identical tests have been used for representative samples on five occasions. On the verbal test, the scores tend to rise up to 1980, whereupon the tendency is reversed. The consequence of these contradictory trends is that the pupils’ verbal ability seems to be the same in 1990 as it was thirty years before. However, behind this stability, big differences on item‐level are hidden. The results on the spatial and the reasoning tests have risen considerably up to 1990. However, the whole increment for the girls, and the largest part of that for the boys, have taken place during the 60's and 70's. The gender differences in all tests are rather small compared to the differences between youngsters with different social backgrounds. However, during the late 80's, the differences between boys and girls, as well as those between social groups have increased. The joint effect of these two tendencies ends up in considerably larger differences between boys from the upper middle‐class and girls from the working‐class.