title: Grouping principles in direct competition.
abstract: We (1) introduce a primed flanker task as an objective method to measure perceptual grouping, and (2) use it to directly compare the efficiency of different grouping cues in rapid visuomotor processing. In two experiments, centrally presented primes were succeeded by flanking targets with varying stimulus-onset asynchronies (SOAs). Primes and targets were grouped by the same or by different grouping cues (Exp. 1: brightness/shape, Exp. 2: brightness/size) and were consistent or inconsistent with respect to the required response. Subjective grouping strength was varied to identify its influence on overall response times, error rates, and priming effects, that served as a measure of visual feedforward processing. Our results show that stronger grouping in the targets enhanced overall response times while stronger grouping in the primes enhanced priming effects in motor responses. Also, we obtained differences between rapid visuomotor processing and the subjective impression with cues of brightness and shape but not with cues of brightness and size. Our findings establish the primed flanker task as an objective method to study the speeded visuomotor processing of grouping cues, making it a useful method for the comparative study of feedforward-transmitted base groupings (Roelfsema & Houtkamp, 2011).
authors.affiliation: University of Kaiserslautern, Social Sciences, Experimental Psychology, Erwin-Schrödinger-Str. Geb. 57, D-67663 Kaiserslautern, Germany. filipp.schmidt@sowi.uni-kl.de
authors.forename: Filipp
authors.initials: F
authors.lastname: Schmidt
authors.forename: Thomas
authors.initials: T
authors.lastname: Schmidt
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D003463:Cues; D004192:Discrimination, Psychological; D005260:Female; D005556:Form Perception / Q000502:physiology; D006801:Humans; D008029:Lighting; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time; D012858:Size Perception / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: Grouping by brightness; Grouping by shape; Grouping by size; Perceptual grouping; Response priming