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Hannah Filmer, Jason Mattingley, Paul Dux; Object Substitution Masking for an Attended and Foveated Target. Journal of Vision 2015;15(12):887. doi: https://doi.org/10.1167/15.12.887.
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© ARVO (1962-2015); The Authors (2016-present)
Visual masking can be used to prevent conscious detection and discrimination of a target image. Of the different types of masking, object substitution masking (OSM) is thought to be unique in that it arises only when attention is distributed across several possible target locations. However, several recent findings have suggested that the apparent interaction between distributed spatial attention and masking magnitude in OSM may reflect ceiling effects in performance. We report definitive evidence that OSM does not depend upon attention being distributed over space or time. In two experiments, we used constant, foveal presentations of a single target stimulus. Unmasked performance at discriminating the orientation of a line within the target was thresholded to 70% accuracy to avoid floor and ceiling limits to performance. Thresholding was achieved via manipulating the contrast of a forward mask (Experiment 1) or the transparency of the target (Experiment 2). After thresholding, an OSM mask consisting of four-dots was presented with simultaneous onset, and variable offset, relative to the target. Crucially, participants’ attention was always focused on the target. Our results demonstrate reliable OSM with attended and foveated stimuli, thus discounting the hypothesis that a key requirement for OSM is distributed attention. The findings challenge how OSM is conceptualized in the broader masking literature and have important implications for theories of visual processing.
Meeting abstract presented at VSS 2015
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