title: Perceptual load modulates attentional capture by abrupt onsets.
abstract: The abrupt appearance of a new object captures attention, even when the object is task irrelevant. These findings suggest that abrupt onsets capture attention in a stimulus-driven manner and are not susceptible to top-down influences on attentional control. However, previous studies examining the ability of abrupt onsets to capture attention have used search displays that lacked significant complexity. Because attention is a limited capacity mechanism, it is possible that increasing the complexity, or perceptual load, of the search arrays may modulate capture by abrupt onsets. We used a flanker task to examine the effect of perceptual load on attentional capture by abruptly appearing objects. Subjects searched for a target letter through low-load (set size = 1) and high-load (set size = 6) displays. On each trial, irrelevant flankers also appeared, one as an onset and the other as an offset. Onset flankers affected search in low-load but not high-load displays. This modulation of attentional capture was not caused by generalized slowing when subjects searched through high-load displays; search for a single perceptually degraded target slowed response times but did not affect attentional capture. These findings demonstrate that attentional capture by an abrupt onset is attenuated when people search through high-load scenes.
authors.affiliation: University of Iowa, Iowa City, IA 52242-1407, USA. joshua-cosman@uiowa.edu
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Cosman
authors.forename: Shaun P
authors.initials: SP
authors.lastname: Vecera
mesh_terms: D001288:Attention; D015350:Contrast Sensitivity; D004192:Discrimination, Psychological; D006801:Humans; D008570:Memory, Short-Term; D009949:Orientation; D010364:Pattern Recognition, Visual; D011930:Reaction Time