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)

Results from a representative sample of 123 adults in the United Kingdom tested with the Wechsler Adult Intelligence Scale-Revised and a test of word identification time are in line with previous findings that speed of information processing is significantly related to performance IQ but not to verbal IQ. (SLD)

The performance on a battery of cognitive tests of an individual with extraordinary ability at mental arithmetic was studied. Implications of the rather ordinary test performance of Shakuntala Devi in contrast with her calculating speed are discussed with reference to memory and information processing. (SLD)

The influences of memory load and encoding on sex differences in performance of comparison and decision processes--matching digits and letters--were studied in 3 experiments with 189 male and 188 female college students. A sex difference in comparison processes may be influenced by the code used when making comparisons. (SLD)

Individual differences in retention, with an emphasis on their relationship with learning speed and other cognitive factors, were studied in 685 military recruits. In all of the forgetting conditions, the fastest learners remembered more and relearned faster. Results support the existence of individual differences in retention. (SLD)

Cognitive processes underlying the empirical correlation between IQ and choice reaction time (CHRT) were examined using the Culture Fair Intelligence Test and nine CHRT tasks (N=50 university students). IQ predicted well for simple control tasks and available attention, but not for attention flexibility, feature extraction, or response choices…

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…

Measures of four-choice reaction time, inspection time, and scores on a speeded coding-substitution task obtained from 104 adults aged 54 to 85 years were found to account for almost all age-related changes in cognitive performance on a number of indices of general fluid ability. (SLD)

In 2 studies with 85 and 88 undergraduates, respectively, peripheral nerve conduction velocity (NCV) was significantly correlated with IQ score and reaction times, and NCV and reaction time contributed significantly, in combination, to prediction of IQ. Results are interpreted in terms of a neural efficiency model of intelligence. (Author/SLD)

The validity of the fourth edition of the Stanford-Binet (S-B IV) test was studied with 30 linguistically precocious children at ages 20, 24, and 30 months. Validity at 24 months was questionable. Problems in using the test with very young children are discussed. (SLD)

Comments on the work of Arthur Jensen, specifically "The g Factor" (1998), which consolidates the psychometric, neurophysiological, behavior genetic, and comparative evidence for the existence and importance of a factor of general intelligence ("g"). Discusses Jensen's work on black/white differences in intelligence. (SLD)

Discusses the contributions of Arthur Jensen to the study of intelligence and considers his writings on the topic of racial differences in scores on tests of intelligence. Concludes with a discussion of his work on the correlates of the "g" vector (general intelligence factor). (Author/SLD)

Administered a battery of psychometric ability tests to 211 undergraduates and 622 other adults ranging in age from 43 to 78. Findings were consistent with the view that speed of information processing can be an important correlate of individual differences in rates of intellectual aging and a performance-specific confound that distorts estimates…

There are several studies showing that working memory and intelligence are strongly related. However, working memory tasks require simultaneous processing and storage, so the causes of their relationship with intelligence are currently a matter of discussion. The present study examined the simultaneous relationships among short-term memory (STM),…

In experimental time estimation research, it has consistently been found that the more a person is engaged in some kind of demanding cognitive activity within a given period of time, the more experienced duration of this time interval decreases. However, the role of individual differences has been largely ignored in this field of research. In a…