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Citation |
Shalev L, Mevorach C. J. Vis. 2013; 13(9): 223. |
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Copyright |
(Copyright © 2013, Association for Research in Vision and Ophthalmology) |
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DOI |
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PMID |
unavailable |
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Abstract |
Top-down attention selection can involve both excitatory processes (biasing attention towards targets) and inhibitory ones (biasing attention away from distracters). In fact, it seems that normal ageing has a differential effect on these two types of processes: While excitatory guidance may be stronger (Madden et al., 1999), inhibitory processes may be selectively weaker in ageing (Lustig et al., 2007). Though the degraded inhibition might be compensated by increased excitatory guidance, performance could be impaired in those scenarios where high-salience distracters compete for selection. In the present study we compared performance of young and old adults in a salience-based selection task which enabled us to separate competition for response from competition for perceptual representation. Superimposed faces and scenes where used in which either the face or the scene was more salient than the other. In Experiment 1 participants identified the face (ignoring the scene) or the scene (ignoring the face) while in Experiment 2 only the face had to be identified (and therefore the scenes did not elicit competing responses). Old adults showed an extraordinary impairment in identifying faces/scenes when the scenes/faces had high-salience but this only happened in the response competition condition (Experiment 1). When response competition was eliminated old adults' performance was comparable to young adults. The results support previous studies that have demonstrated impaired inhibition of incongruent distracters in ageing (Zhou et al., 2011) while further emphasizing that normal aging entails impaired ability to resolve conflicting responses rather than conflicting stimuli. Moreover, the results mimic our previous findings with left parietal patients (Mevorach et al., VSS 2012; using a similar design) and may therefore raise the hypothesis that degraded left parieto-occipital circuitry is the cause for reduced inhibitory top-down attention in old age. Language: en |