Abstract: | The question, whether schooling exerts a substantial influence on the development of intelligence is an issue of ongoing discussion. In our study we (a) present a quasi-experimental design to separate schooling effects from effects of chronological age and (b) apply it to intelligence test data of (n = 578) 10-year-old children. The results show that there are considerable schooling effects on all tests, including the tests of fluid intelligence, and that schooling effects explain most all of the intellectual progress made during 1 year of life at that age, measured by the increase in the mean scores of the tests. |