Is Time-Sharing a General Ability

The time-sharing ability of 18 students was measured under 8 separate dual-task (double-stimulation) conditions. Three task characteristics -- input modality (auditory or visual), output modality (vocal or manual) and task difficulty (easy or difficult) -- were systematically varied across conditions in an effort to manipulate the nature of the specific time-sharing demands imposed. Each condition contained two of these characteristics in common with 3 of the remaining 7 conditions, one of the characteristics in common with 3 others, and none in common with the last condition. Time-sharing efficiency was found to correlate across conditions that impose similar processing demands on the individual, but not across conditions imposing relatively dissimilar demands. We conclude on this basis that time-sharing performance is largely determined by several poorly corelated, task-specific subcapacities rather than by a single general capacity or ability. (Author)