Personality variations in population: intelligence

The present study was designed to chart the distribution of cognitive factors in an adult population. The material consisted of a representative sample of persons aged 18-65 years, living in the county of Stockholm (except for the city of Stockholm) in 1970. The total selection was 3 064 persons. These persons were invited to a hospital for a health examination, covering both physical and mental health. Psychometric tests were included. In the study of cognitive factors the rate of non-response corresponded to 18.7% of the sample (males 20.7%, females 16.6%). The tool of examination was the Dureman-Sälde test battery. It is shown that men score rather higher than women in analytical and spatial but not in verbal ability. Analytical ability declines steadily throughout the age spectrum. Spatial ability shows a declining trend from he age group 36-45 years. Verbal ability is best in the age group 36-45 years and here the reduction in higher ages is very limited. A positive correlation of considerable degree exists between social group and the intelligence factors. This applies particularly to verbal and spatial ability and the overall measures. The connection with logical-inductive ability is quantitatively much less impressive. As regards verbal and spatial ability, there is an age-related tendency to a widened gap between social groups. Standardization for social group in tests is advocated in practical use.