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Visual Appearances of the Metric Shapes of Three-Dimensional Objects: Variation and Constancy

Yu, Ying
http://orcid.org/0000-0002-1142-5499
http://rave.ohiolink.edu/etdc/view?acc_num=osu1592254922173432

Abstract Details

2020, Doctor of Philosophy, Ohio State University, Psychology.
The current research program seeks to explain a phenomenal visual experience. Namely, appearances of the shapes of three-dimensional (3D) rigid objects remain to be rigid when we walk around and view them from different angles and distances. This is a hard problem to solve given the ambiguities arising from the optical projection and constantly changing retinal images as we navigate. Two hypotheses were proposed. Hypothesis 1 explains this phenomenon by arguing that the visual system can reconstruct the 3D shape veridically. Alternatively, Hypothesis 2 argues that even though the reconstructed 3D shape is distorted with viewpoint, the resulting nonrigidity in the 3D shape percepts is not detected by the visual system under ordinary circumstances. Eight psychophysical experiments were conducted to test the two hypotheses by investigating the perception of 3D metric shape of well-structured polyhedral objects from binocular stereopsis. In Experiment 1 to 7, participants adjusted the 3D shape of an adjustable object to match the perceived 3D shape of a reference object under a variety of conditions. In Experiment 8, participants discriminated a nonrigid polyhedral object from a rigid one in an immersive virtual reality environment. Results of the eight experiments reported in this thesis reject Hypothesis 1 and support Hypothesis 2. Thus, the phenomenal rigid appearance of rigidly moving objects does not arise from the veridical perception of 3D shape. Rather, the 3D metric shape percepts vary systematically with viewing distance (Experiment 1, 4, 7), object size (Experiment 2), in-plane orientation (Experiment 3), different types of optical projection (Experiment 4, 5, 6), and scene context (Experiment 7). And testing with more symmetric objects or in a more naturalist scene context cannot make the perception more accurate (Experiment 7). However, a comparison between participants' performance in Experiment~8 with their performance in Experiment 1, 4, or 7 suggests that the amount of difference in 3D metric shape that is detectable when comparing two stationary objects synchronically becomes undetectable when it manifests in a single object diachronically during motion. In conclusion, the current research program shows that it is possible to have a change in the appearance of the shape of a 3D object without having any appearance of change of shape of this object.
Alexander Petrov (Advisor)
James Todd (Committee Member)
Julie Golomb (Committee Member)
Declan Smithies (Committee Member)
201 p.
Psychology
3D shape perception; stereopsis; metric shape; psychophysics; visual appearance; rigid motion; philosophy of perception; phenomenal visual experience; symmetry; structural regularities; hierarchical Bayesian

Recommended Citations

Citations

  • Yu, Y. (2020). Visual Appearances of the Metric Shapes of Three-Dimensional Objects: Variation and Constancy [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1592254922173432

    APA Style (7th edition)

  • Yu, Ying. Visual Appearances of the Metric Shapes of Three-Dimensional Objects: Variation and Constancy. 2020. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1592254922173432.

    MLA Style (8th edition)

  • Yu, Ying. "Visual Appearances of the Metric Shapes of Three-Dimensional Objects: Variation and Constancy." Doctoral dissertation, Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1592254922173432

    Chicago Manual of Style (17th edition)

osu1592254922173432
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This open access ETD is published by The Ohio State University and OhioLINK.