Wf. Bacon et He. Egeth, GOAL-DIRECTED GUIDANCE OF ATTENTION - EVIDENCE FROM CONJUNCTIVE VISUAL-SEARCH, Journal of experimental psychology. Human perception and performance, 23(4), 1997, pp. 948-961
Conjunctive visual search is most difficult when distracter types ate
in equal proportions and gets easier as the proportions diverge (e.g.,
E. Zohary & S. Hochstein, 1989). This may reflect restriction of sear
ch to the feature shared by the target and the less-frequent distracte
r. Alternatively, such effects could reflect target salience, which va
ries with distracter ratio. In 2 experiments, 60 participants searched
64-element displays for a conjunctive target among distracters of 2 t
ypes in various proportions. Participants were correctly informed (Exp
eriment 1) or misinformed (Experiment 2) about which distracter type w
ould be less frequent on most trials. In both experiments, the distrac
tor-ratio effect was significantly influenced by the information provi
ded to participants. These findings demonstrate the efficacy of top-do
wn information in guiding attention and show that it can be applied fl
exibly, weighted toward particular target features.