Dynamic testing is an assessment method in which training is incorporated into the procedure with the aim of gauging cognitive potential. Large individual differences are present in children's ability to profit from training in analogical reasoning. The aim of this experiment was to investigate sources of these differences on a dynamic test of…

According to the cognitive cascade hypothesis, age-related slowing results in decreased working memory, which in turn affects higher-order cognition. Because recent studies show complex associative learning correlates highly with fluid intelligence, the present study examined the role of complex associative learning in cognitive cascade models of…

Many explanations have been proposed for the evolution of our anomalously large brains, including social, ecological, and epiphenomenal hypotheses. Recently, an additional hypothesis has emerged, suggesting that advanced cognition and, by inference, increases in brain size, have been driven over evolutionary time by the need to deal with…

Many aspects of cognition decline from middle to late adulthood, but the dimensionality and generality of this decline have rarely been examined. We analyzed 20-year longitudinal data of 6203 middle-aged to very old adults from Greater Manchester and Newcastle-upon-Tyne, UK. Participants were assessed up to eight times on 20 tasks of fluid…

A high-quality estimate of the mean IQ of a country requires giving a well-validated test to a nationally representative sample, which usually is not feasible in developing countries. So, we used a convenience sample and four corrections based on theory and empirical findings to arrive at a good-quality estimate of the mean IQ in Bali. Our study…

It has been proposed that males would show higher mean scores than females in general intelligence ("g") because (1) men have, on average, larger brains than women, and (2) brain volume correlates with "g." Here we report a failure to support the conclusion derived from these premises. High resolution MRIs were acquired in a sample of one hundred…

The analysis of sex differences in cognitive abilities is largely confusing because these differences are masked by the pervasive influence of the general factor of intelligence (g). In this study a battery of five reasoning tests (abstract [AR], numerical [NR], verbal [VR], mechanical [MR], and spatial [SR]) was completed by a sample of 3233…

The cognitive abilities involved in the Connections (Salthouse, et al., 2000) version of the trail making test were investigated by administering the test, along with a battery of cognitive tests and tests of complex span and updating conceptualizations of working memory, to a sample of over 3600 adults. The results indicate that this variant of…

This article presents three studies, two of them longitudinal, which investigated the relations between age, processing speed, working memory (WM), and fluid intelligence ("g[subscript f]") from 4 to 16 years of age. Structural equation modeling showed that speed was a powerful covariate of age ([approximately] - 0.6 to - 0.7) from 4 to 13 years,…

Here we apply a method for automated segmentation of the hippocampus in 3D high-resolution structural brain MRI scans. One hundred and four healthy young adults completed twenty one tasks measuring abstract, verbal, and spatial intelligence, along with working memory, executive control, attention, and processing speed. After permutation tests…

Longitudinal change in five cognitive abilities was investigated to determine if the direction or magnitude of change was related to the individual's ability level. Adults between 18 and 97 years of age performed three versions of 16 cognitive tests on two occasions separated by an average of 2.7 years. In order to control for influences…

In two experiments the neuronal mechanisms of sex differences in mental rotation were investigated. In Experiment 1 cortical activation was studied in women and men with similar levels of mental rotation ability (high, and average to low), who were equalized with respect to general intelligence. Sex difference in neuroelectric patterns of brain…

Sex differences in the latent general and broad cognitive abilities underlying the Differential Ability Scales, Second Edition were investigated for children and youth ages 5 through 17. Multi-group mean and covariance structural equation modeling was used to investigate sex differences in latent cognitive abilities as well as changes in these…

In 1977 Draw-a-Person test was administered to fifth grade school children in a city and its surrounding rural villages in Turkey. In 2010, more than thirty years later, the test was administered again to a corresponding group of fifth grade children in the same locations. It is rare that we get scores from the "same" population over a…

National IQs and measures of technological development given by Comin, Easterly and Gong (2010) are presented for 133 nations for the year 1000 BC, for 134 nations for 0 AD, for 120 nations for 1500 AD and for 133 nations for 2000 AD. It is shown that national IQs are significantly correlated with national differences in technological development…