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Tandra Ghose, Frouke Hermens, Michael Herzog; How the global layout of the mask influences masking strength. Journal of Vision 2013;13(9):826. doi: 10.1167/13.9.826.
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© ARVO (1962-2015); The Authors (2016-present)
Visual masking is typically explained by local interactions between mask elements and the target. However, Hermens & Herzog (2007) showed that the global spatial layout of the mask, rather than its local structure, determines masking strength. Here we investigate how global aspects of luminance and timing influence masking strength.
A vernier target was followed by a mask of 25 aligned verniers. Participants were asked to report the offset direction of the target vernier.
Masking is weak when all mask elements are of the same length, luminance, and are displayed at the same time. When the two mask elements directly next to the vernier are longer, performance deteriorates dramatically. The same holds true if the elements are of higher or lower luminance or are displayed with a short delay. Masking energy cannot explain these local effects because higher and lower luminance elements increase masking. When every second mask element is longer, performance improves compared to when only the neighboring lines are longer- even though these elements are part of both conditions. Hence, the global mask layout, rather than some local aspects, determines masking strength. However, this does not hold true for luminance manipulations which seem to be determined by the directly neighboring lines. For temporal conditions, a complex non-monotonic pattern is found. Clearly, masking strength cannot be explained by simple models based on local interactions alone. We argue that these findings should be taken into account when masking is used as a tool to investigate visual perception.
Meeting abstract presented at VSS 2013
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