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Kerem Ozkan, Myron Braunstein; Change detection for objects on surfaces slanted in depth. Journal of Vision 2009;9(8):916. doi: https://doi.org/10.1167/9.8.916.
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© ARVO (1962-2015); The Authors (2016-present)
Change detection for objects associated with a surface extended in depth might be more difficult than for a frontal surface if it is easier to shift attention within a frontal surface. On the other hand, previous research has shown that ground surfaces have a special role in organizing the 3D layout of objects shown against scene backgrounds. In the current study we examined whether a frontal background or a ground surface background would result in superior change detection performance. Observers were presented with a set of scenes in a change detection flicker paradigm. Each trial consisted of an original scene (250 ms), a blank interval (250 ms) and a modified scene (250 ms), repeated until the observer responded. Each original scene contained 21 3D cylinders against a background of alternating black and white vertical stripes. The backgrounds were frontal-parallel or slanted 63, 79 or 82 deg. The modified scenes were produced by removing one of the cylinders from the original scene. Catch trials were included in which there was no difference between the alternating scenes. The observer's task was to identify whether or not there was a change. Only trials in which the observer correctly identified a change were used in the analysis. The results showed a significant effect of surface slant on the number of exposures required to detect a change. Fewer trials were required to detect a change in the frontal and 82 deg conditions. Detection took longer for intermediate slant values. This suggests that any superiority of frontal plane backgrounds in a change detection task may be equivalent to the superiority of a near-ground plane in organizing a scene, with the lowest level of performance occurring for surfaces that are not frontal but further from a ground surface orientation.
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