Saccadic eye movements and dual-task interference.
Four dual-task experiments required a speeded manual choice response to a tone in a close temporal proximity to a saccadic eye movement task. In Experiment 1, subjects made a saccade towards a single transient; in Experiment 2, a red and a green colour patch were presented to left and right, and the saccade was to which ever patch was the pre-specified target colour. There was some slowing of the eye movement, but neither task combination showed typical dual-task interference (the "psychological refractory effect"). However, more interference was observed when the direction of the saccade depended on whether a central colour patch was red or green, or when the saccade was directed towards the numerically higher of two large digits presented to the left and the right. Experiment 5 examined a vocal second task, for comparison. The findings might reflect the fact that eye movements can be directed by two separate brain systems--the superior colliculus and the frontal eye fields; commands from the latter but not the former may be delayed by simultaneous unrelated sensorimotor tasks.
Pashler
H
H
Department of Psychology, University of California, San Diego, La Jolla 92093.
Carrier
M
M
Hoffman
J
J
D001288:Attention; D001307:Auditory Perception; D003118:Color Perception; D006801:Humans; D011597:Psychomotor Performance; D011930:Reaction Time; D012438:Saccades / Q000502:physiology; D013647:Task Performance and Analysis