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Christopher Jones, Lauren Williams, Trafton Drew; Does this grab your attention? A comparison of attention and memory resources deployed during search for artificial and real world objects.. Journal of Vision 2018;18(10):521. doi: https://doi.org/10.1167/18.10.521.
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© ARVO (1962-2015); The Authors (2016-present)
Current theories of visual search posit that search is guided by the maintenance of an attentional template of the search target. This template is thought to be maintained in working memory (WM) for novel targets and in long-term memory for repeated targets. In previous experiments this has been measured using the Contralateral Delay Activity (CDA: Vogel & Machizawa, 2004). The CDA reflects the maintenance of information in visual WM. As targets repeat, the CDA decreases in amplitude, suggesting decreased reliance on the attentional template in WM (Carlisle et al. 2011). We wondered whether this decrease varies as a function of object type. In these experiments, electroencephalographic activity was recorded while participants completed a visual search task in which they searched for a target repeated for six trials in a row. In Experiment 1, the decrease in CDA amplitude across repetitions was compared between artificial stimuli (Landolt Cs) and images of real-world objects. The CDA amplitude decreased across trials at the same rate for both real-world objects and Landolt Cs, suggesting that the two types of stimuli are similarly represented in WM despite differences in visual characteristics, semantic association and search difficulty. In contrast to the WM representation of the target, initial selection appears to be strongly modulated by object type. The amplitude of the N2pc (a component related to attentional selection) increased after the first target repetition when searching for objects, but did not increase across Landolt C repetitions. This was an unexpected result and was replicated in a separate experiment. It appears that repeated exposure to real-world target objects sharpens selection mechanisms associated with these objects. This suggests that search for real-world objects engages attention in a fundamentally different manner than search for artificial stimuli even though both are similarly represented in WM.
Meeting abstract presented at VSS 2018
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