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J. Farley Norman, Ashley Bartholomew; The effects of sex and age upon the perception of 3-D shape from deforming and static boundary contours. Journal of Vision 2008;8(6):860. doi: https://doi.org/10.1167/8.6.860.
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© ARVO (1962-2015); The Authors (2016-present)
A single experiment was designed to investigate how younger and older observers perceive 3-D shape from deforming and static boundary contours (i.e., silhouettes). On any given trial, observers were shown two randomly-generated, smoothly curved 3-D objects, and were required to judge whether they possessed the “same” or “different” shape. The objects presented during the “different” trials obviously produced different boundary contours. The objects presented during the “same” trials also produced different boundary contours, because one of the objects was always rotated in depth relative to the other (about a Cartesian vertical axis) by either 5, 25, or 45 degrees. Each observer judged 30 pairs of objects for a total of 12 experimental conditions (360 total trials). These conditions were formed by the orthogonal combination of 2 motion types (moving vs. static boundary contours), 2 display types (objects depicted either as silhouettes or with texture and lambertian shading), and 3 angular offsets (5, 25, & 45 degrees). The observers' discrimination ability was measured using d'. The results showed that overall, there was no effect of age: older observers performed just as well as younger observers. There was, however, a main effect of sex: males performed better than females, regardless of age. This superiority in performance for males was higher for objects depicted as silhouettes than for objects depicted with texture and shading (thus triggering a sex x texture interaction). Increases in the magnitude of the angular offset led to deteriorations in discrimination performance. The effect of the increases in angular offset, however, was different for the younger and older age groups, and was also different for males and females. Overall, the results reveal that human observers can effectively utilize the information present in boundary contours to support their perception of 3-D shape, and that this ability persists throughout life.
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