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Abstract: This study examined the relationships among short-term memory (STM), working memory (WM), and general intelligence (g). Two independent samples of participants performed several verbal, quantitative, and spatial STM and WM tasks, as well as a broad set of tests measuring psychometric intelligence. The constructs are carefully sampled to include heterogeneous tasks and tests to control the effect of unwanted variance. The results have several points of interest. First, there is a strong correlation between STM and WM. Second, WM is a slightly better predictor of g than STM. Third, when the correlation between STM and WM is statistically controlled, the unique predictive power of WM is small, which suggests that the short-term storage component of the WM system largely drives the relationship between WM and g. [Copyright &y& Elsevier]

Abstract: Evidence from neuroimaging studies suggests that intelligence differences may be supported by a parieto-frontal network. Research shows that this network is also relevant for cognitive functions such as working memory and attention. However, previous studies have not explicitly analyzed the commonality of brain areas between a broad array of intelligence factors and cognitive functions tested in the same sample. Here fluid, crystallized, and spatial intelligence, along with working memory, executive updating, attention, and processing speed were each measured by three diverse tests or tasks. These twenty-one measures were completed by a group of one hundred and four healthy young adults. Three cortical measures (cortical gray matter volume, cortical surface area, and cortical thickness) were regressed against psychological latent scores obtained from a confirmatory factor analysis for removing test and task specific variance. For cortical gray matter volume and cortical surface area, the main overlapping clusters were observed in the middle frontal gyrus and involved fluid intelligence and working memory. Crystallized intelligence showed an overlapping cluster with fluid intelligence and working memory in the middle frontal gyrus. The inferior frontal gyrus showed overlap for crystallized intelligence, spatial intelligence, attention, and processing speed. The fusiform gyrus in temporal cortex showed overlap for spatial intelligence and attention. Parietal and occipital areas did not show any overlap across intelligence and cognitive factors. Taken together, these findings underscore that structural features of gray matter in the frontal lobes support those aspects of intelligence related to basic cognitive processes. [Copyright &y& Elsevier]