This study investigated the systematic rise in cognitive ability scores over generations, known as the "Flynn Effect," across middle childhood and early adolescence (7-15 years; 291 monozygotic pairs, 298 dizygotic pairs; 89% White). Leveraging the unique structure of the Louisville Twin Study (longitudinal data collected continuously…

In this study of two hundred and thirty 8- to 13-year-olds, a new "Silent Films" task is introduced, designed to address the dearth of research on theory of mind in older children by providing a film-based analogue of F. G. E. Happe's (1994) Strange Stories task. Confirmatory factor analysis showed that all items from both tasks loaded…

Cognitive impairment is common among children born very preterm (VPT), yet little is known about how this risk changes over time. To examine this issue, a regional cohort of 110 VPT (= 32 weeks gestation) and 113 full-term (FT) born children was prospectively assessed at ages 4, 6, 9, and 12 years using the Wechsler Preschool and Primary Scale of…

A large-scale ("N" = 552) controlled multivariate prospective 14-year longitudinal study of a developmental cascade embedded in a developmental system showed that information-processing efficiency in infancy (4 months), general mental development in toddlerhood (18 months), behavior difficulties in early childhood (36 months),…

The verbal, performance, and full-scale IQs of the standardization sample for the Wechsler Intelligence Scale for Children--Revised (WISC-R) were analyzed according to sex, race, geographic region, parental occupation, and type of residence (urban or rural) and compared with corresponding data from a 1950 study of the WISC standardization sample.…

Cognitive ability of nondiabetic children and early and late onset diabetic children was compared. Diabetic children scored in the normal range in intelligence and academic performance, but showed evidence of school difficulties and memory deficiencies. Children's perceived self-competence and parents' reports of children's functioning and…

Tests causal models of verbal and performance IQ in 69 Mexican-American children of low socioeconomic status. Years of mother's education were correlated with IQ at 3 years and at 6 to 8 years, but traditional/nontraditional attitudes showed conflicting correlations over time. The adequacy of standarized IQ tests for this population is questioned.…