Eye movements during search for coded and uncoded targets

Eye movements and search time of four subjects were studied as they searched for a target dial in a 4 х 4 array of dials which were differentiated by (1) color, (2) shape, (3) a combination of color and shape, or (4) were uncoded. Subjects did not exhibit a characteristic scanpath, and method of scanning did not relate to search time. Search time varied reliably among conditions; it was generally shortest in the color condition, followed by color shape, shape, and the uncoded condition. Subjects were capable of using both shape and color simultaneously. Search time was strongly associated with the average number of fixations required for target detection but not with other measures of eye movements. Fixation duration was a particularly inconsistent measure.