COHORT EFFECTS IN COGNITIVE DEVELOPMENT OF CHILDREN AS REVEALED BY CROSS-SECTIONAL SEQUENCES

A recently proposed bifactorial developmental model consisting of the factors of age and cohort was tested by using cross-sectional sequences as data-collection strategies. In each of 2 studies, age was varied in 2 levels (8:4 and 8:8, 9:4 and 9:8) and cohort (birth date) in 3 levels (July 1955, November 1955, and March 1956; July 1956, November 1956, and March 1957). 4 subtests of intelligence from the Begabungste system were administered to 2 random samples of 420 Ss with 35 boys and 35 girls in each treatment condition. Using an analysis of variance design, significant main effects of age and cohort as well as significant interactions were found for some of the 4 measures of cognitive functioning. It is argued that the obtained cohort effects represent differential amounts of schooling rather than season-of-birth effects. The findings clearly support the necessity of the bifactorial developmental model which calls for sequential strategies to disentangle age from cohort effects in developmental research. (20 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1969 American Psychological Association.