The relationship between the ability to divide attention and standard measures of general cognitive abilities

This study focused on individual differences in the ability to allocate processing resources among competing tasks and its relationship with general cognitive ability. Fifty participants performed three single tasks and two types of dual tasks composed of pairs of the single tasks. Two single tasks and one dual task were repeated three times. Individual differences in dual task performance exhibited satisfactory levels of test-retest reliabilities. In addition, performance on the dual tasks could not be completely accounted for by performance on the single tasks. The dual task variance unaccounted for by the single tasks was found to be stable and consistent, indicating that the ability to allocate resources is a distinct ability. Furthermore, various types of data analyses indicated that dual task performance better predicts a measure of general cognitive ability [the Inter-University Psychometric Entrance Test (PET)] than the single tasks in the first administration of the tasks but not in subsequent administrations. These results imply that the unique ability to perform the dual tasks may become more automatic and less controlled with practice, and thus its relationship with general cognitive ability declines.