In a population-based sample of 112 nine-year old twin pairs, we investigated the association among total brain volume, gray matter and white matter volume, intelligence as assessed by the Raven IQ test, verbal comprehension, perceptual organization and perceptual speed as assessed by the Wechsler Intelligence Scale for Children-III. Phenotypic…

The mental representations and processes used in verbal comprehension were studied in 2 preliminary studies and 2 experiments involving a total of 158 college students solving synonym or sentence completion tasks. Response choices and latencies could be predicted with explicit information-processing models. Implications for theories of…

Results of two experiments involving 206 upper elementary school students supported the hypothesis that less-skilled readers suffer working memory deficits that contribute to comprehension problems independent of their problems in phonological coding. Results also suggest that constraints in an executive system may contribute to reading…

It is shown how typical analyses of strategic behavior focus on the "problem of remembering" based on the experimenter's conceptualization of optimum task performance. A new definition of a strategy is suggested in which strategies are seen as attempts to solve the "problem of remembering" as understood by the person. (Author/LMO)

Explored the contribution of two working memory systems, the articulatory loop and the central executive, and short-term memory to the word recognition and comprehension deficits of children with learning disabilities. Results of 2 experiments with 150 children support the idea that poor word recognition and comprehension reflect deficits in a…

Three experiments involving 85 learning-disabled (LD) children and 101 non-LD children investigated whether memory difficulties of LD children may be attributable in part to executive processing. Results suggest that LD readers may suffer from executive processing deficiencies, although they do not rule out effects of language-specific processes.…

Reaction time and movement time were negatively and moderately-to-strongly correlated with Ravens matrices performance and with reading comprehension and performance on the California Test of Basic Skills for 20 ninth-grade girls. Weaker relationships were found for mathematics and English grades, although the direction was consistently negative.…

A correlation exists between verbal ability test scores and name identity minus physical identity reaction times in a letter matching task. The present results support Carroll's (1981) suggestion that the reaction time difference is related more to speed than power component of standardized tests and is not optimum for prediction. (Author/RD)