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Shiau-Hua Liu, Barbara Anne Dosher, Zhong-Lin Lu, Pamela Jeter; Incompatibility of the object-judgment reference frames has costs in dual-object report deficits. Journal of Vision 2007;7(9):643. doi: 10.1167/7.9.643.
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© ARVO (1962-2015); The Authors (2016-present)
Attributes of different visual objects are often less accurately reported than separate attributes of the same object, a behavioral pattern theoretically associated with the limitations of object attention. Object attention has evolved as an organizing principle for cortical mechanisms of visual object attention (Desimone, 1998). However, Han, Dosher, &Lu (Psych. Science, 2003) showed that large dual-object report deficits in discrimination thresholds occurred only when different judgments (i.e., orientation and phase of Gabors) but not same judgments (orientations or phases) were made for two spatially separated objects. Given this and previous literature, we predicted that different judgment frames, as well as different features, could impose dual object costs. The current study tests this prediction of dual-object report deficit using distinct frames to report the same simple feature dimension. Subjects judged the orientation (+/− 18 deg) in two spatially separated (5 dva) Gabors oriented around the same ( or / /) or different (? and V) diagonal base angles or frames. In dual report (DR) conditions, orientation was judged for both objects in a cued order. For single report (SR) conditions, only one cued object was reported. Contrast psychometric functions showed significant DR deficits (SR-DR) for different frame but not for same frame conditions for four subjects - especially in the presence of high external (white) Gaussian noise. A similar small effect occurred in noiseless conditions. A fifth subject was also affected by frame consistency, but showed DR deficits in all conditions. These results, then, support the influence of judgment frames in dual-object attention paradigms. The nature of the attention effect is more robust in high external noise, identifying external noise exclusion as an important function of dual-object attention. These judgment frame effects may have implications for human performance in complex visual displays.
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