Sex differences in the latent general and broad abilities underlying the Kaufman Assessment Battery for Children-Second Edition (KABC-II) were investigated for children and youth ages 6 through 18. The data were split into different age groups to account for changes due to differential development. Multi-group higher-order analysis of mean and…

Based on the construct of classical IQ, a model of the proportions of the population at various stages of cognitive development as a function of age is proposed. The model compares well with other theoretical models and provides evidence of the salience of the construct of general cognitive capacity. (SLD)

Recent literature suggests a causal link between malnutrition and impaired cognitive development. A selective literature review indicates that the presence or absence of such a link cannot be established. A reanalysis of an experiment indicated after four years of treatment there was no association between cognitive and nutritional status.…

The domain-independent and domain-dependent approach to the evolution of cognition have been taken by separate groups of researchers who have focused exclusively on either the formal properties or the distinct cognitive demands of tasks. We express the view that synthesizing the two approaches could lead to a more complete understanding, and…

A three-stage model for the evolution of theories of intelligence is proposed and applied to understanding the evolution of correlationally based and experimentally based theories of intelligence. In stage one, alternative conceptions compete. In subsequent stages, alternative conceptions, which combine elements of prior approaches, emerge and…

Whether results previously found in adults, demonstrating a relationship between intellectual ability, speed of information processing, and memory capacity could be found in young children was studied with 109 children. Findings suggest that children's intelligence cannot be explained using a model of adult intelligence. (SLD)

This article summarizes results from studies of the organization and development of cognitive abilities in adults aged 20 to 60 years old. Theories of intelligence stipulating a hierarchy of intellectual functions, with fluid and crystallized intelligence at the top, are supported. Six conclusions on age differences are offered. (Author/RD)

The analysis or modeling of Piagetian and psychometric measures of mental ability is discussed. An application of structural modeling procedures allowing the testing of hypotheses in this domain is presented. Such a model is illustrated through a study of numerical functional relations tasks with 77 elementary school students. (SLD)

Raven's Progressive Matrices test items were analyzed for M demand (Pascual-Leone's developmental construct). Data on second- and third-grade subjects were analyzed for extent of absolute agreement of Raven and Figural Intersection Test (FIT) scores. Raw scores on the Raven could be deduced on the basis of FIT performance. (Author/RD)

The construct of general intelligence is discussed in the context of factor models, differential validity of tests, Piagetian tasks, heritability, social class, and race. The general factor is an abstraction resulting from genes, environmental pressures, and neural structures involved in cognitive or intellectual human behavior. (Author/RD)

Disparities between European countries and the U.S. in terms of incidence and prevalence of mild mental retardation have become apparent. A model of intellectual performance that might explain disparities and predict future levels of occurrence of mild mental retardation is presented. Such explanations are relevant for theory and policy decisions.…