Using data from the Swedish Individual Statistics Project, changes in intelligence among 13-year olds are documented over a 25-year period. The average spatial and reasoning intelligence has risen successively. A clear increase is found for verbal intelligence in the 1960s, with more irregular growth since then. (SLD)

Changes in intelligence among Swedish 13-year-olds during a 20-year period was studied. Results show: (1) the average of spatial and reasoning intelligence has risen; (2) verbal intelligence increased during the 1960s, but declined thereafter; and (3) by the 1980s girls surpassed in verbal ability and equalled in spatial ability. (Author/LMO)

Changes in verbal, spatial, and reasoning intelligence among Swedish 13-year olds were studied from 1960 to 1990. Rising verbal scores until 1980 have been followed by a decline to essentially the 1960 level. Spatial and reasoning results have risen continuously. Gender and social class differences are discussed. (SLD)

This study investigated possible changes in verbal, spatial, and reasoning intelligence in Swedish 13-year-olds over a 20-year period. The first sample included about 12,000 students born in 1948. Data consisted of (1) information from school records, (2) information on personal background, (3) scores on three intelligence tests and three…