Young adults, originally tested as infants for their ability to process information as measured by selective attention to novelty (an operational definition of visual recognition memory), were revisited. A current estimate of IQ was obtained as well as a measure of academic achievement. Information processing ability at 6-12 months was predictive…

Studied the interrelationships among general fluid intelligence, short-term memory capacity, working memory capacity, and processing speed in 120 young adults and used structural equation modeling to determine the best predictor of general fluid intelligence. Results suggest that working memory capacity, but not short-term memory capacity or…

The relationship between brain size and intelligence was examined in 90 normal volunteers. Results support the notion of a modest relationship between brain size and measures of global intelligence and suggest diffuse brain involvement on performance tasks that require integration and use of multiple cognitive domains. (Author/SLD)

Comments on the other papers in this theme issue and presents a speculative account of inspection time (IT). IT is viewed as an index of core information-processing ability that has a causal influence on the development of complex intellectual skills. (Author/SLD)

Examined the relationships between the latencies of theoretically corresponding and noncorresponding component processes across diverse tasks derived from the structure of intellect model. Results for 72 participants provide evidence that corresponding component processes are generalizable while noncorresponding component processes are not. (SLD)

The aims of this study were to investigate whether the executive functions, inhibition, shifting, and updating, are distinguishable as latent variables (common factors) in children aged 9 to 12, and to examine the relations between these executive functions and reading, arithmetic, and (non)verbal reasoning. Confirmatory factor analysis was used…

The Zahlen-Verbindungs-Test (ZVT) represents a highly feasible measure of information-processing speed that correlates quite highly with standard psychometric tests of intelligence. The present study was designed to identify specific stages of the sensorimotor processing system that may account for individual differences in overall variability of…

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…

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…

Administered marker tests for 5 of the constructs described in the Gf-Gc theory (fluid ability-crystallized ability) of cognitive abilities to 64 adults who also completed inspection time estimation. Results were consistent with the proposition that general intelligence depends exclusively or substantially on speed of processing. (SLD)

Despite certain limitations, factor analysis aids in the identification and characterization of cognitive processes. Variables manipulated for this purpose must be well constructed psychometrically, and it is desirable to dissect tasks into hypothesized components and to use factor analysis in conjunction with other techniques. Well-known…

The relationship between mental speed and IQ was studied with 120 adults who completed a battery of elementary cognitive tests (ECTs). As expected, high speed of information processing on ECTs was related to high psychometric intelligence, but this relationship could not be localized at the level of general intelligence. (SLD)

Studied the contribution of mental speed to task performance on reasoning tasks under timed and untimed conditions for 227 participants and for 90 participants working under time conditions. Results suggest that the use of speeded reasoning tests is likely to lead to overestimates of the relation between mental speed and reasoning ability. (SLD)

A critical review of the theoretical basis and empirical results of the frequency accrual speed test (FAST) developed by D. Vickers and others (1993) leads to the conclusion that the FAST is not appropriately described as an alternative to the inspection time (IT) task, and that results from FAST are not generalizable to IT. (SLD)

Examined alternative models of the pattern of relations among age and variables representing distinct cognitive factors in data from a study involving 206 adults ages 18 to 84 years. Models with a single age-related influence were surprisingly accurate at reproducing the age correlations on the variables. The best fit was for a hierarchical model…