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P. R. DeLucia, M. K. Kaiser, A. Garcia, B. T. Sweet; Effects of relative size and height in field on absolute judgments of time to contact. Journal of Vision 2001;1(3):312. doi: 10.1167/1.3.312.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose. Previous studies indicate that while time-to-contact (TTC) information is specified veridically in optic flow (Lee, 1974), TTC judgments are influenced by other information sources such as relative size (DeLucia, 1991, 1995). DeLucia, et al. (ARVO, 2000) measured the influence of five depth-information sources on absolute and relative TTC judgments. Results suggested that the rules by which information sources are integrated may depend on the task. Here we focus on depth cues of relative size (S) and height in field (H), and assess whether TTC moderates the effects of these cues on a prediction-motion task. Method. With computer simulations of two approaching objects, we factorially combined the presence/absence of H with three levels of S, and two levels of TTC and final distance. When a cue was present, it indicated that the left object was farther away. Sixteen Os pressed a button when they thought the target object would reach the observation plane; the difference between TTC estimates for left and right objects was measured. Results. There were significant main effects for S and H, but no interactions. While TTC estimates increased as actual TTC increased for each object separately, effects of the cues did not depend on TTC. Conclusions. Relative size and height in field can affect TTC judgments. The effects of multiple sources of pictorial depth information and the manner in which they combine must be considered in models of TTC perception. CR: None.
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