Psychophysiological aspects of selective and divided attention during continuous manual tracking

Central, autonomic, and metabolic physiological measures were observed concurrently along with performance and subjective measures to compare the effects of tracking task difficulty during selective and divided attention. Eighteen dextral males performed visual compensatory manual tracking as a primary task while attending to or ignoring secondary-task auditory oddball stimuli. The difficulty of the tracking task was varied factorially by requiring participants to track with acceleration (second-order) or velocity (first-order) control and high or low bandwidth sum-of-sines disturbance. Tracking performance was affected by the difficulty manipulations but not by the attention manipulation. Event-related brain potential P300 amplitude to oddball target stimuli was sensitive to the division of attention and tracking order-of-control but not to tracking disturbance bandwidth when the oddball task was attended. Oxygen consumption, a measure of aerobic metabolism, was greater during acceleration than velocity tracking; however, cardiac measures were sensitive only to the division of attention. The results demonstrate that the attention and the task difficulty manipulations have physiologically dissociable effects that were interpreted as supporting a cognitive/energetic model of attention.