Aging-related declines occur in many different domains of cognitive function during middle and late adulthood. However, whether a global dimension underlies individual differences in changes in different domains of cognition and whether global genetic influences on cognitive changes exist is less clear. We addressed these issues by applying…

Irrespective of the grading system, grades are the most valid instrument for predicting educational success. Previous studies have shown that criterion-referenced compulsory school grades are multidimensional, reflecting subject-specific dimensions and a common grade dimension, both of which contribute to the predictive validity of grades. This…

There is uncertainty about the proportion of children with autism spectrum disorders who do not develop phrase speech during the preschool years. The main purpose of this study was to examine this ratio in a population-based community sample of children. The cohort consisted of 165 children (141 boys, 24 girls) with autism spectrum disorders aged…

Previous analyses have identified a genetic contribution to the correlation between declines with age in processing speed and higher cognitive abilities. The goal of the current analysis was to apply the biometric dual change score model to consider the possibility of temporal dynamics underlying the genetic covariance between aging trajectories…

The importance of cognitive and language skills on reading and spelling development were investigated in a cross-linguistic longitudinal study of 737 English-speaking children (US/Australia) and 169 Scandinavian children (Norway/Sweden) from preschool to Kindergarten and Grade 1. The results revealed that phonological awareness and print knowledge…

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)

Collected data on twins' performance on 13 cognitive variables measured three times at three-year intervals. Twins were monozygotic or dizygotic pairs reared together or apart and were in six cohorts ranging in age from 41 through 84 years. Found stable mean cognitive performance across time on eight measures for the younger cohorts, and…

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)

Assessed the quality of home and out-of-home care environments, child temperament, and the development of verbal abilities among infants at 18 months and then at 8 years of age. Found that both tested and rated cognitive abilities at age 8 were related to earlier measures of verbal ability and to paternal involvement during preschool years. (MOK)

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…

This longitudinal study examined the experiences of out-of-home preschool child care to performance and adjustment in elementary school. Subjects were 145 children in Goteborg, Sweden, who were on average 16 months of age when they were enrolled in this study. Within 4 weeks of enrollment in the study, 54 children began center-based day care, 36…