The general factor in short-term memory, intelligence, and reaction time

Abstract

This study investigated the notion of the generality of the general intelligence factor ( g) across three relatively homogeneous and relatively distinct batteries of ability measures. A short-term memory battery, the Multidimensional Aptitude Battery (MAB) and a reaction time battery were administered to 170 subjects in four 1-hour test sessions. Significant intercorrelations among the component scores generated for the first unrotated (or general) component derived from each battery were obtained. Furthermore, partial correlations demonstrated that controlling for the short-term memory g substantially decreased the correlation between the reaction time g and the MAB g, suggesting that short-term memory mediates the relationship between intelligence and reaction time. Regression analyses revealed that although both the short-term memory g and the reaction time g could significantly predict the MAB g, the short-term memory g was the better predictor. In addition, a second reaction time component, orthogonal to the first and representing a long-term memory factor, was found to significantly increase the prediction of the MAB g beyond that predicted by the reaction time g. Results not only support the notion of the generality of g, but also implicate short-term memory as being an essential aspect of intelligence. The results also demonstrate that general intelligence is not a unitary construct, but comprises at least two distinct components.