USING EYE SACCADES TO ASSESS THE SELECTIVITY OF SEARCH MOVEMENTS

The degree of selectivity or guidance underlying search was tested by having subjects search for a target (a red vertical or green horizonta l bar) among Similar (red horizontal and green vertical bars) and Diss imilar distracters (blue and yellow diagonal bars). If search is indee d a guided process, then the Dissimilar items should not be given the same scrutiny as elements sharing a feature with the target. The frequ ency of eye movements directed to the two distracter types was used as an indicator of this scrutiny. The analysis revealed almost equal per centages of saccades to Similar and Dissimilar elements (55% and 45%, respectively). Although indicating some evidence for selectivity durin g oculomotor search, this finding suggests that simpler and less optim al strategies may undermine the more efficient guided search algorithm . Copyright (C) 1996 Elsevier Science Ltd.