title: Aging and the discrimination of 3-D shape from motion and binocular disparity.
abstract: Two experiments evaluated the ability of younger and older adults to visually discriminate 3-D shape as a function of surface coherence. The coherence was manipulated by embedding the 3-D surfaces in volumetric noise (e.g., for a 55 % coherent surface, 55 % of the stimulus points fell on a 3-D surface, while 45 % of the points occupied random locations within the same volume of space). The 3-D surfaces were defined by static binocular disparity, dynamic binocular disparity, and motion. The results of both experiments demonstrated significant effects of age: Older adults required more coherence (tolerated volumetric noise less) for reliable shape discrimination than did younger adults. Motion-defined and static-binocular-disparity-defined surfaces resulted in similar coherence thresholds. However, performance for dynamic-binocular-disparity-defined surfaces was superior (i.e., the observers' surface coherence thresholds were lowest for these stimuli). The results of both experiments showed that younger and older adults possess considerable tolerance to the disrupting effects of volumetric noise; the observers could reliably discriminate 3-D surface shape even when 45 % of the stimulus points (or more) constituted noise.
authors: Department of Psychology & Center for the Study of Lifespan Development, Western Kentucky University, Bowling Green, KY 42101-1030, USA. Farley.Norman@wku.edu
authors: J Farley
authors: JF
authors: Norman
authors: Jessica S
authors: JS
authors: Holmin
authors: Amanda M
authors: AM
authors: Beers
authors: Jacob R
authors: JR
authors: Cheeseman
authors: Cecilia
authors: C
authors: Ronning
authors: Angela G
authors: AG
authors: Stethen
authors: Adam L
authors: AL
authors: Frost
mesh_terms: D000293:Adolescent; D000368:Aged; D000375:Aging / Q000523:psychology*; D001288:Attention; D003867:Depth Perception; D004193:Discrimination Learning; D004192:Discrimination, Psychological; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009039:Motion Perception; D009949:Orientation; D010364:Pattern Recognition, Visual; D012016:Reference Values; D013499:Surface Properties; D015357:Vision Disparity; D055815:Young Adult