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Markus Conci, Qi-Yang Nie, Hermann J. Müller; Attention and memory resolution in visual search for hierarchical objects. Journal of Vision 2013;13(9):154. doi: 10.1167/13.9.154.
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© ARVO (1962-2015); The Authors (2016-present)
Objects can be represented at multiple hierarchical levels, but typically, more global object levels receive precedence over more local levels. Here, we explored how object hierarchy affects the resolution of attention and memory using a visual search task with Navon letters as global/local targets and non-targets. Our results show that search for targets defined at the global level was more efficient than search for comparable local-level targets. Moreover, this global precedence effect on attention was transferred to memory, as an analysis of cross-trial contingencies revealed priming to occur only for global targets but not for local targets. Subsequent experiments manipulated the prevalence of global and local targets to investigate the stability of this global/local processing asymmetry. When local targets were presented more frequently than global targets (i.e. local targets on 75% of all trials), global precedence was overall reduced and priming occurred at both object levels. In addition, when systematically changing the prevalence of global and local targets throughout the experiment, attention showed a dynamic hierarchical adjustment according to target prevalence. In contrast, memory (priming) was unaffected by changes in target prevalence. In sum, our findings demonstrate that hierarchical object structure is represented beyond mechanisms of perceptual organization, as global precedence affects the resolution of both attention and memory. However, both processes show different underlying dynamics, with transient object-level adjustments occurring in attention but not in memory.
Meeting abstract presented at VSS 2013
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