In an argument for orthogonal variables to explain intelligence, higher-order constructs, including "g" as a single thing in intelligence, are suggested to inevitably result from complex systems with interrelated parts. Biological reductionism and other arguments for the higher-order constructs as explanations of intellectual functioning…

Cluster analysis, applied to Carroll's cognitive theory, indicates that the obtained clusters make intuitive sense and imply that taxonomy is possible. Moreover, some clusters are similar to those suggested by other theories, especially the theory of fluid and crystallized intelligence. (Author/CP)

The generality of ability factor structure in adulthood and old age was investigated. Data were analyzed for 198 young individuals (15-32 years), 156 younger old individuals (53-68 years), and 156 older old individuals (69-91). Variables were nine tests marking three ability factors. (Author/CTM)

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)

This study explored the structure of elementary cognitive tasks (ECTs) and relations between the corresponding construct(s) with processing speed (Gs) and fluid intelligence (Gf). Participants (N=321) completed 14 ECTs, 3 Gs, and 6 Gf marker tests, all administered in paper-and-pencil format to reduce potential confounds evident when tasks are…

This study examined whether a timesharing factor can be identified when a number of competing tasks are presented in the midst of a range of single tests designed to sample a broad range of psychological dimensions. A battery of single and competing tasks was presented to 126 subjects. (Author/LMO)

The hierarchical and radex models of ability organization are shown to be parallel. Both suggest a complexity continuum for cognitive performance tasks which, in the radex model, corresponds to the general-to-specific dimension in factor analyses. The bases for this continuum indicate its importance for theories of intelligence. (Author/RD)

Relationships among Piagetian reasoning assessments and standard measures of intelligence and achievement were determined in 1972 by Stephens, McLaughlin, Miller, and Glass (EJ 055 112). The data were reanalyzed by Humphreys and Parsons in 1979 (EJ 218 642). In reply, Glass and Stephens note fallacies in Humphreys' and Parsons' reasoning.…

Stephens et al. (EJ 055 112) committed a serious methodological error in holding chronological age constant in their IQ measures and allowing it to vary in their Piagetian developmental measures. This error is unrelated to differences in factor rotation methods used by these authors and was not answered in their reply. (CTM)

These authors cite their own study of the relationship between traditional measures of intelligence and Piagetian measures of cognitive development in support of Glass and Stephens' contention that there are important qualitative differences. They question Humphreys' and Parsons' conclusions on both substantive and factor theoretical grounds. (CTM)