Patterns of eye movements during parallel and serial visual search tasks

Eye movements were monitored while subjects performed parallel and serial search tasks. In Experiment la, subjects searched for an ''O'' among ''X''s (parallel condition) and for a ''T'' among ''L''s (serial condition). In the parallel condition of Experiment Ib, ''sic'' was the target and ''(O)''s were distracters; in the serial condition, these stimuli switched roles. Displays contained 1, 12, or 24 stimuli, with both target-present and target-absent trials. RT and eye-movement measures (number of fixations, saccadic error, and latency to move) indicated that search efficiency was greatest in the parallel conditions, followed by the serial condition of Experiment la and, finally, by the serial condition of Experiment Ib. This suggests that eye movements are correlated with the attentional processes underlying visual search.