Using more complex items than those commonly employed within the information-processing approach, but still easier than those used in intelligence tests, this study analyzed how the association between processing speed and accuracy level changes as the difficulty of the items increases. The study involved measuring cognitive ability using Raven's…

The existence of general-purpose cognitive mechanisms related to intelligence, which appear to facilitate all forms of problem solving, conflicts with the strong modularity view of the mind espoused by some evolutionary psychologists. The current study assessed the contribution of general intelligence ("g") to explaining variation in…

In the present study, speeded tasks with differing assumed difficulties of the trials are regarded as a special class of simple cognitive tasks. Exploratory latent growth modeling with data-driven shape of a growth curve and nonlinear structured latent curve modeling with predetermined monotonically increasing functions were used to analyze…

Mental chronometry (MC) studies cognitive processes measured by time. It provides an absolute, ratio scale. The limitations of instrumentation and statistical analysis caused the early studies in MC to be eclipsed by the "paper-and-pencil" psychometric tests started by Binet. However, they use an age-normed, rather than a ratio scale, which…

Psychometric intelligence correlates with reaction time in elementary cognitive tasks, as well as with performance in time discrimination and judgment tasks. It has remained unclear, however, to what extent these correlations are due to top-down mechanisms, such as attention, and bottom-up mechanisms, i.e. basic neural properties that influence…

Elementary cognitive tasks (ECTs) are simple tasks involving basic cognitive processes for which speed of performance typically correlates with IQ. Inspection time (IT) has the strongest IQ correlations and is considered critical evidence for neural speed underlying individual differences in intelligence. However, results from Bors et al. [Bors,…

The worst performance rule for cognitive tasks [Coyle, T.R. (2003). IQ, the worst performance rule, and Spearman's law: A reanalysis and extension. "Intelligence," 31, 567-587] in which reaction time is measured is the result that IQ scores correlate better with longer (i.e., 0.7 and 0.9 quantile) reaction times than shorter (i.e., 0.1 and 0.3…

Higher cognitive function is associated with faster choice reaction time (CRT), and both are associated with a reduced risk of mortality from all-causes and cardiovascular disease (CVD). However, comparison of the predictive capacity of CRT, an emerging risk factor, with that for established "classic" risk factors for mortality, such as…

The impurity of measures is considered as cause of erroneous interpretations of observed relationships. This paper concentrates on impurity with respect to the relationship between working memory and fluid intelligence. The means for the identification of impurity was the fixed-links model, which enabled the decomposition of variance into…

Research is reviewed to show that the weakness of the reaction time slope parameter (b) of the Hick function x IQ correlation is mainly attributable to statistical artifacts that suppress the parameter's correlation with any other variables, such as the intercept and IQ. Conditions that reduce this suppression are reviewed. (SLD)

Explored the relationship of both simple and four-choice reaction time to scores for the Alice Heim 4 (AH4) test to assess whether correlations previously reported adequately represented the strength of the relationship and to test for departures from linearity. Findings for 900 adolescents and adult show the correlation to be a good summary for…

In a study involving 38 adult females, nerve conduction velocity (NCV) did not correlate with intelligence or reaction time. A reanalysis of the Vernon and Mori data showed a possible sex difference in relation to NCV and intelligence, with the correlation between these variables much smaller in females than males. (SLD)

Nerve conduction velocity (NCV) and efficiency of synaptic transmission are two possible biological mechanisms that may underpin intelligence. Direct assessments of NCV, without synaptic transmission, show few substantial or reliable correlations with cognitive abilities ["Intelligence" 16 (1992) 273]. We therefore assessed the latencies…

Using a simple neural model comprising between two and four neurons, it is concluded that speed of neuron conduction is not the probable basis of the intelligence quotient (IQ)-reaction time (RT) correlation. This result illustrates that neural modeling can be applied to biological theories of individual differences in intelligence. (SLD)

Two samples of adult subjects of reasonably average intelligence were given IQ tests and a series of reaction time tests using 0, 1, 2, and 3 lists of information in a Hick paradigm. (Author/LMO)