Age-related decline in global form suppression.
Visual selection of illusory 'Kanizsa' figures, an assembly of local elements that induce the percept of a whole object, is facilitated relative to configurations composed of the same local elements that do not induce a global form--an instance of 'global precedence' in visual processing. Selective attention, i.e., the ability to focus on relevant and ignore irrelevant information, declines with increasing age; however, how this deficit affects selection of global vs. local configurations remains unknown. On this background, the present study examined for age-related differences in a global-local task requiring selection of either a 'global' Kanizsa- or a 'local' non-Kanizsa configuration (in the presence of the respectively other configuration) by analyzing event-related lateralizations (ERLs). Behaviorally, older participants showed a more pronounced global-precedence effect. Electrophysiologically, this effect was accompanied by an early (150-225 ms) 'positivity posterior contralateral' (PPC), which was elicited for older, but not younger, participants, when the target was a non-Kanizsa configuration and the Kanizsa figure a distractor (rather than vice versa). In addition, timing differences in the subsequent (250-500 ms) posterior contralateral negativity (PCN) indicated that attentional resources were allocated faster to Kanizsa, as compared to non-Kanizsa, targets in both age groups, while the allocation of spatial attention seemed to be generally delayed in older relative to younger age. Our results suggest that the enhanced global-local asymmetry in the older age group originated from less effective suppression of global distracter forms on early processing stages--indicative of older observers having difficulties with disengaging from a global default selection mode and switching to the required local state of attentional resolution.
Department of Psychology, Ludwig-Maximilians-Universität München, Leopoldstr. 13, 80802 München, Germany; Center for Visual Cognition, Department of Psychology, University of Copenhagen, Øster Farimagsgade 2A, 1353 København, Denmark; Graduate School of Systemic Neurosciences, Ludwig-Maximilians-Universität München, Großhaderner Str. 2, Planegg-Martinsried, 82152, Germany. Electronic address: iris.wiegand@psy.ku.dk.
Iris
I
Wiegand
Department of Psychology, Ludwig-Maximilians-Universität München, Leopoldstr. 13, 80802 München, Germany.
Kathrin
K
Finke
Department of Psychology, Ludwig-Maximilians-Universität München, Leopoldstr. 13, 80802 München, Germany; Graduate School of Systemic Neurosciences, Ludwig-Maximilians-Universität München, Großhaderner Str. 2, Planegg-Martinsried, 82152, Germany.
Thomas
T
Töllner
Department of Psychology, Ludwig-Maximilians-Universität München, Leopoldstr. 13, 80802 München, Germany.
Kornelija
K
Starman
Department of Psychology, Ludwig-Maximilians-Universität München, Leopoldstr. 13, 80802 München, Germany; School of Psychological Sciences, Birkbeck College, University of London, Malet Street, London WC1E 7HX, UK.
Hermann J
HJ
Müller
Department of Psychology, Ludwig-Maximilians-Universität München, Leopoldstr. 13, 80802 München, Germany.
Markus
M
Conci
D000328:Adult; D000368:Aged; D000375:Aging / Q000523:psychology*; D001288:Attention / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology
Cognitive Aging; Event-related potentials; Global-local Processing; Inhibition deficit; Kanizsa figures; N2-posterior contralateral (N2pc); Posterior contralateral negativity (PCN)