title: Attentional set interacts with perceptual load in visual search.
abstract: In the present study, we examined the hypothesis that perceptual load is the primary factor that determines the efficiency of attentional selection. Participants performed a visual search task under conditions of high- and low-load. In line with the perceptual load hypothesis, presenting conditions of high- and low-load in separate blocks of trials resulted in processing of to-be-ignored stimuli only in the low-load condition (Experiment 1). However when high- and low-load conditions were randomly mixed in blocks of trials, the participants showed processing of to-be-ignored stimuli in both conditions, suggesting that high perceptual load is not necessarily sufficient to obtain perceptual selectivity (Experiment 2). An analysis of intertrial transition effects showed that on high-load trials, processing of to-be-ignored stimuli occurred only when the previous trial was a low-load trial. The results suggest that low perceptual load can engender broad attentional processing. On the other hand, when a high-load trial was preceded by another high-load trial, little processing of task-irrelevant stimuli was observed. The present results are discussed in terms of the interaction between expectancies and bottom-up factors in the efficiency of attentional selection.
authors.affiliation: Vrije Universiteit, Amsterdam, the Netherlands. j.theeuwes@psy.vu.nl
authors.forename: Jan
authors.initials: J
authors.lastname: Theeuwes
authors.forename: Arthur F
authors.initials: AF
authors.lastname: Kramer
authors.forename: Artem V
authors.initials: AV
authors.lastname: Belopolsky
mesh_terms: D001288:Attention; D006801:Humans; D011930:Reaction Time; D014796:Visual Perception