To assess whether movement artifacts reported in visual inspection time (IT) tasks were under metacognitive control, 29 young adults in Edinburgh (Scotland) were tested on a dual-task paradigm in which IT was conducted along with a concurrent task. Reports of movement artifacts are not usually examples of metacognitive processing. (SLD)

To estimate Flynn effects (FEs) on forms of declarative memory (episodic, semantic) and visuospatial ability (Block Design) time-sequential analyses of data for Swedish adult samples (35-80 years) assessed on either of four occasions (1989, 1994, 1999, 2004; n = 2995) were conducted. The results demonstrated cognitive gains across occasions,…

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)

The effects of controlling for individual differences in simple reaction time (RT) on the correlations of choice RT and discrimination RT with intelligence quotient were studied for 213 male college students. Simple RT was controlled by subtraction, partial correlation, and multiple correlation. (SLD)

Studied whether genetic variability explained some of the variance in coincidence timing and whether common genetic factors accounted for the association with intellectual functioning using 55 pairs of 16-year-old twins. Results suggest that the genetic influence operating on coincidence timing skills was of similar magnitude to that of response…

The aim of this study was to identify promising endophenotypes for intelligence in children and adolescents for future genetic studies in cognitive development. Based on the available set of endophenotypes for intelligence in adults, cognitive tasks were chosen covering the domains of working memory, processing speed, and selective attention. This…

The relation between general intelligence (psychometric "g") and temporal resolution capacity of the central nervous system was examined by assessing performance on eight different temporal tasks in a sample of 100 participants. Correlational and principal component analyses suggested a unitary timing mechanism, referred to as temporal "g".…

Jensen has reported reaction-time (RT) studies indicating that various parameters correlate significantly with IQ. Two parameters of interest are slope of RT across set size and increasing correlations of RT with IQ as set size increases. After reviewing these studies, the author concludes that Jensen's claims are unwarranted. (Author/BW)

Correlations between elementary sensory tasks and IQ scores support Galtonian theories of intelligence, which emphasize speed of signal encoding and transmission in the nervous system. Research involving 73 male Navy recruits indicates that such theories are warranted only when elementary tasks are viewed separately. Task complexity in…

By comparing the profile of "g" loadings for a set of psychometric test scores, it is shown that general intelligence is related to timed performance measures from perceptual-motor tasks, more strongly on more complex tasks. The profile of the "g" loadings was predictable from the response-time (RT) psychometric test time correlations for four RT…

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…

Examples of claims about racial differences in intelligence that are not supported by scientific evidence are presented, with focus on several studies by A. R. Jensen. Relevant questions that should be addressed by students of racial differences are presented. (SLD)

Whether results previously found in adults, demonstrating a relationship between intellectual ability, speed of information processing, and memory capacity could be found in young children was studied with 109 children. Findings suggest that children's intelligence cannot be explained using a model of adult intelligence. (SLD)