The decay and interruption of interactions between search mechanisms

The attentional mechanisms in the brain responsible for fast pop-out search and slower difficult search have been shown to interact. Even if pop-out search is interrupted, by the addition of extra distractors to an initially simple search display, the partial computations calculated by the mechanisms responsible for pop-out can facilitate subsequent difficult search ("search assistance"; Psychon. Bull. Rev. 7 (2000) 292; Vision Res. 40 (2000) 891). With the present experiments, we aimed to discover whether search assistance is disrupted when the display that affords pop-out search disappears before the appearance of the display that must be examined by difficult search. Search assistance was not disrupted by the insertion of a blank screen in between the first and second portions of the display (Experiment 1). Search assistance for target-present trials was not disrupted by the insertion of black disks in between the first and second portions of the display (Experiment 2), but this manipulation did disrupt search assistance for target-absent trials. Implications for the relationship between search assistance and visual marking of distractors (Psychol. Rev. 104 (1997) 90) are discussed.