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Zheng Bian, George Andersen; Aging and egocentric distance judgments in 3-D scenes. Journal of Vision 2009;9(8):69. doi: 10.1167/9.8.69.
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Previous studies have shown age-related decrements in various perceptual tasks. In the current study we examined whether there is an age-related difference in judging egocentric distance in 3-D scenes. In two experiments older and younger observers viewed an outdoor scene (a large lawn field) and judged the egocentric distance of a target positioned at varying distances. Two tasks were used: verbal response and blind-folded rope pulling. In Experiment 1 the physical distance of the target (4, 6, 8, 10, or 12m) and viewing condition (monocular or binocular) were manipulated. The order of viewing condition was counterbalanced across observers. On each trial an observer looked at the target in the scene and determined its physical distance. The observer was encouraged to scan the ground plane between his/her feet and the target. Observers then either verbally reported the physical distance or put on an eye-mask and pulled a rope to match the physical distance of the target. Overall, we found older observers reported more depth than younger observers. Younger observers showed foreshortening (a well documented finding in the literature). Older observers on average made highly accurate responses. In Experiment 2, we examined if this age-related difference in egocentric distance judgment was due to difference in internal scale. On each trial a 3-feet long rod was positioned horizontally in front of the observer and observers were instructed to use the rod as a reference when judging the distance of the target. For the rope pulling task the same length was shown to the observer on the rope. Only binocular viewing was examined. The results were similar to that obtained in Experiment 1, suggesting that age-related differences in egocentric distance judgments were not due to differences in internal scale.
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