Most psychometric tests of spatial ability are paper-and-pencil tasks at the ''figural'' scale of space, in that they involve inspecting, imagining or mentally transforming small shapes or manipulable objects. Environmental spatial tasks, such as wayfinding or learning the layout of a building or city, are carried out in larger spaces that…

Mildly retarded young adults were given simple and choice reaction time (RT) tests. Subjects' RTs increased with stimulus complexity. RTs of retarded subjects were slower and evidenced more intraindividual variability than those of nonretarded subjects. Several RT parameters were related to measures of intelligence. (Author/RD)

Latent dimensions underlying individual differences in performance of information-processing tasks and dual task combinations, and the existence of a time-sharing (TS) ability were studied in 81 male college students. Supportive evidence for a general TS ability was not found. An identified TS factor specific to task combinations is discussed.…

This article analyzes if working memory (WM) is especially important to understand "g." WM comprises the functions of focusing attention, conscious rehearsal, and transformation and mental manipulation of information, while "g" reflects the component variance that is common to all tests of ability. The centrality of WM in individual differences in…

Because they used an inappropriate statistical procedure, J. H. Kranzler and A. R. Jensen (1991) have not demonstrated that a factor of general intelligence ("g") depends on several independent factors. A factorial reanalysis of their data suggests that speed and efficiency of information processing are important in "g." (SLD)

The hypothetical idea of a perfectly pure psychometric "g" is empirically unattainable. Because the unity of "g" cannot be proved or disproved by factor analysis, the unitary "g" hypothesis represents a parsimonious assumption. J. B. Carroll's (1991) analysis demonstrates the relationship between psychometric and…

A critique by Carroll of a study by Jarman and Das (EJ 171 820) is refuted in terms of the methodology and theory of the Jarman and Das study. Additionally, two general issues concerned with individual differences in cognitive processes and strategic behavior are elaborated beyond Carroll's discussion. (Author/CP)

Measurements derived from reaction time, movement time, and an index of neural adaptability derived from averaged evoked potentials are significantly related to each other as well as to g factor scores extracted from a battery of 15 psychometric tests in a sample of 54 severely retarded adults. (Author/RD)

Scores on ability tests given to 1,274 students in grades 4-6 and 1,310 in grades 7-9 were simultaneously factor analyzed at class and individual levels. At the individual level, the general factor was most highly loaded on fluid abilities. Three common factors were established at the class level. (SLD)