Eye-movement control in direction-coded visual search

Subjects searched for a target among distractors which were arranged random ly or such that each distracter provided information about the relative pos ition of a target. Trials were presented either in a blocked design (so tha t the subjects knew a priori the contextual information in the display) or in a mixed design. When the distracters provided information about target p osition, there were (i) shorter manual RTs, (ii) fewer fixations made in se arch of the target, (iii) longer mean fixation durations, (iv) shorter init ial fixation durations, (v) shorter mean gaze shifts, (vi) a smaller area o f Fixation dispersion, and (vii) a greater percentage of optimally directed saccades. Except for gaze shifts, the results were uninfluenced by whether or not there was a blocked or a mixed presentation. The results of the stu dy suggest that despite noise in the search mechanism, fixation durations w ere adjusted to process directly the currently fixated element(s).