Showing papers by "J. Farley Norman published in 2009"
TL;DR: Results underscore the importance of anterior IPS regions in the processing of 3D shape, in agreement with their proximity to grasping-related regions, and indicate that DIPSA and DIPSM may represent human homologues for the posterior part of AIP and the adjoining part of LIP respectively.
120 citations
TL;DR: It is demonstrated that older observers (at least through the age of 83 years) can effectively extract information about slant in depth from optical patterns containing texture, motion parallax, or binocular disparity.
Abstract: The ability of younger and older observers to perceive surface slant was investigated in four experiments. The surfaces possessed slants of 20 degrees, 35 degrees, 50 degrees, and 65 degrees, relative to the frontoparallel plane. The observers judged the slants using either a palm board (Experiments 1, 3, and 4) or magnitude estimation (Experiment 2). In Experiments 1-3, physically slanted surfaces were used (the surfaces possessed marble, granite, pebble, and circle textures), whereas computer-generated 3-D surfaces (defined by motion parallax and binocular disparity) were utilized in Experiment 4. The results showed that the younger and older observers' performance was essentially identical with regard to accuracy. The younger and older age groups, however, differed in terms of precision in Experiments 1 and 2: The judgments of the older observers were more variable across repeated trials. When taken as a whole, the results demonstrate that older observers (at least through the age of 83 years) can effectively extract information about slant in depth from optical patterns containing texture, motion parallax, or binocular disparity.
37 citations
TL;DR: The results showed that the discrimination of 3-D object shape from cast shadows was generally invariant over the distortions produced by hemispherical background surfaces, and observers often had difficulty in identifying the shadows cast onto saddle-shaped background surfaces.
16 citations
TL;DR: It appears that human observers can recognize the three-dimensional shape of objects in a manner that is relatively independent of size.
15 citations
TL;DR: The current findings of an age-related deterioration in the ability to discriminate lifted weight extend and disambiguate the results of earlier research.
Abstract: A single experiment was carried out to evaluate the ability of younger and older observers to discriminate object weights. A 2-alternative forced-choice variant of the method of constant stimuli was used to obtain difference thresholds for lifted weight for twelve younger (mean age = 21.5 years) and twelve older (mean age = 71.3 years) adults. The standard weight was 100 g, whereas the test weights ranged from 85 to 115 g. The difference thresholds of the older observers were 57.6% higher than those of the younger observers: the average difference thresholds were 10.4% and 6.6% of the standard for the older and younger observers, respectively. The current findings of an age-related deterioration in the ability to discriminate lifted weight extend and disambiguate the results of earlier research.
10 citations