title: Visual crowding is correlated with awareness.
abstract: Crowding by nearby features causes identification failures in the peripheral visual field. However, prominent visual features can sometimes fail to reach awareness, causing scenes to be incorrectly interpreted. Here we examine whether awareness of the flanking features is necessary for crowding to occur. Flankers that were physically present were rendered perceptually absent with adaptation-induced blindness. In a letter identification task, targets were presented unflanked or with up to four flanker letters. On each trial, observers reported both the number of letters they perceived and the identity of a target letter. This paradigm allowed trial-by-trial assessment of awareness and crowding and ensured that both targets and flankers were attended. Target-letter identification performance was correlated with the number of flanking letters that were perceived on a given trial, regardless of the number that were physically present. Our data demonstrate that crowding can be released when flanking elements at attended locations are suppressed from visual awareness.
authors.affiliation: Schepens Eye Research Institute, Harvard Medical School, Boston, MA 02114, USA. thomas.wallis@schepens.harvard.edu
authors.forename: Thomas S A
authors.initials: TS
authors.lastname: Wallis
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Bex
mesh_terms: D001364:Awareness; D006801:Humans; D010470:Perceptual Masking; D010775:Photic Stimulation; D011930:Reaction Time; D013997:Time Factors; D014794:Visual Fields; D014796:Visual Perception