Figure 1.

(A) Procedure for control experiment. (B) There were four different search displays in the control. The search displays were of set size 4 or 8 and for either feature or conjunction search. (C) Percent accuracy in detection of the presence or absence of the target. The slope for conjunction performance is significantly negative (p < 0.01). (D) Reaction time in detection of the presence or absence of the target. Note: For illustration purposes, the stimuli shown in this figure are of higher contrast than those used in the experiment.