Individual differences in the ability to focus and divide attention

This research deals with individual differences in the ability to focus and divide attention. Eighty-five subjects performed visual search and auditory detection tasks in three conditions: single channel, focused attention, and divided attention. Reaction time (RT) was fastest in the single channel condition, intermediate in the focused attention condition, and longest in the divided attention condition, and these effects were much stronger in the auditory than the visual task. Correlations among RTs in the three conditions were very high within modality (>.88), and lower between modalities (.5 to .6). The correlational data was well fit by a model that included separate factors for the visual and auditory tasks. Measures from the three attentional conditions within each modality loaded equally on these factors. The data provided no evidence for distinct abilities to divide or focus attention.