Studied the extent to which inspection time (IT) relates to psychometric intelligence through general intelligence or through group factors and examined whether IT relates to psychometric intelligence independent from other elementary cognitive tasks. Results for 569 twins aged 6 to 13 years suggest that IT and other elementary tasks predict…

The present study evaluated the criterion validity of the aggregated tasks of basic cognitive processes (TBCP). In age groups from 6 to 19 of the Woodcock-Johnson III Cognitive Abilities and Achievement Tests normative sample, the aggregated TBCP, i.e., the processing speed and working memory clusters, correlate with measures of scholastic…

Hierarchical factor analyses involving Schmid-Leiman transformations were conducted on specific cognitive abilities data collected from 148 identical and 135 fraternal twin pairs from the Western Reserve Twin Project. Model fitting results reflect genetic influences on specific abilities and suggest that environmental influences are less…

Examined the relationship between elementary cognitive tasks and the general factor of intelligence ("g") through tests administered to 568 elementary school students in a study of twins. Findings indicate a memory processing component in addition to a general information processing component contributing to "g" estimates. (SLD)