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Perceptual organization, aging, and the multichannel model

Rosen, Allyson Claudia
http://rave.ohiolink.edu/etdc/view?acc_num=case1057858660

Abstract Details

1994, Doctor of Philosophy, Case Western Reserve University, Psychology.
Organization of the visual world appears to begin early in perceptual processing. An example of perceptual organization is the relative ease with which a target can be found in distractors that differ from the target but are similar (related) to each other. The effect is called pop out because the target appears without an effortful search. The present work attempted to explain this example of preattentive processing in terms of the multichannel model of visual perception. Specifically, low spatial frequency information was postulated to project a global image of an array to the visual system and thus allow preattentive selection of the target. The task was similar to Gilmore, Tobias, and Royer (1985). Subjects searched for a target letter "F" in an array of related distractors or an array of unrelated distractors. There were 3 filter conditions: high pass, low pass, and unfiltered arrays. Because contrast sensitivity may change with increasing age, it is possible that sensitivity to perceptual organization may also change. For example it is possible that elderly people with weakened sensitivities to low spatial frequency information may show a weaker pop-out effect. The deficit may be important for higher cognitive processes because, in general, difficulty organizing information may interfere with the selection of stimuli for focal attention and memory storage. Contrast sensitivity functions were measured for 24 young and 24 elderly subjects. Elderly subjects showed decreased sensitivity to high spatial frequencies (specifically, 8 and 11.4 cpd.) and showed the same pattern of results as young subjects in the search task. Results suggest that both high and low spatial frequencies can convey perceptual organizational information. When low spatial frequencies were reduced in the high pass condition, the pop-out effect was reduced. Removal of low spatial frequencies thus makes visual search less efficient. The discussion also explores how assuming that the visual system does a Fourier analysis may enlighten other theories of visual search in arrays of related distractors.
Grover Gilmore (Advisor)
110 p.
Perceptual organization aging multichannel model

Recommended Citations

Citations

  • Rosen, A. C. (1994). Perceptual organization, aging, and the multichannel model [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1057858660

    APA Style (7th edition)

  • Rosen, Allyson. Perceptual organization, aging, and the multichannel model. 1994. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1057858660.

    MLA Style (8th edition)

  • Rosen, Allyson. "Perceptual organization, aging, and the multichannel model." Doctoral dissertation, Case Western Reserve University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=case1057858660

    Chicago Manual of Style (17th edition)

case1057858660
480
© 1994, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.