title: The time-course of global and local attentional guidance in Kanizsa-figure detection.
abstract: Object configurations can be perceptually represented at various hierarchical levels. For example, in visual search, global Kanizsa figures are detected efficiently, whereas search for local groupings is inefficient, with similarity-dependent nontarget interference arising at the hierarchical level that defines the target (Conci, Müller, & Elliott, 2007). The present study was designed to examine the electrophysiological correlates of this global-local search asymmetry. The results revealed differences between hierarchical object levels to be evident throughout a number of processing stages: search for a global, versus a local, target elicited larger amplitudes in early sensory components (P1, N1). Moreover, the efficiency of attentional orienting towards a target was mirrored in the Posterior Contralateral Negativity (PCN), with PCN latencies being substantially delayed (by ∼ 70 ms) with local, versus global, targets. Finally, late components (P3 and slow wave--SW) reflected the overall search efficiency, which was determined by both the hierarchical level at which the target was defined and the similarity-based nontarget interference. Taken together, this pattern shows that multiple, sequential processes of object completion contribute to the attentional precedence of a globally bound object over a mere local element grouping.
authors.affiliation: Department of Psychology, Ludwig-Maximilians-University, Munich, Germany. conci@psy.lmu.de
authors.forename: Markus
authors.initials: M
authors.lastname: Conci
authors.forename: Thomas
authors.initials: T
authors.lastname: Töllner
authors.forename: Marcin
authors.initials: M
authors.lastname: Leszczynski
authors.forename: Hermann J
authors.initials: HJ
authors.lastname: Müller
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005106:Exploratory Behavior / Q000502:physiology; D005260:Female; D005556:Form Perception / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D008606:Mental Processes / Q000502:physiology; D009903:Optical Illusions; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010466:Perceptual Closure / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology; D055815:Young Adult