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theses

Human beings’ perceptual realities are, at their core, multisensory. Theories of multisensory perception posit that interactions between sensory systems are the product of intersensory agreement between low-level stimulus attributes such as timing, and high-level attributes such as meaning. Whether meaningful associations impact audiovisual action perception has been debated, with some researchers taking the fairly extreme position that effects based on high-level meaningful correspondences are particular to human speech. To address the questions of whether, and if so how, meaningful associations impact the multisensory perception of human actions, ten psychophysical experiments were undertaken. In Experiments 1 and 2, participants detected upright and inverted point-light walkers presented silently within point-light masks, with the sounds of footsteps, or with pure tones. Supporting the hypothesis that meaningful associations influence audiovisual action sensitivity, results revealed superior visual sensitivity to upright walkers with meaningful sounds. Experiments 3 and 4 examined how sounds improve visual action sensitivity; specifically, whether meaningful sounds must be action-matched in order to influence visual action sensitivity. Results were equivocal in regards to the specific research question, but suggest future directions. Experiments 5-6 addressed whether sounds’ influence on visual action sensitivity requires temporal synchrony. Results implied that meaningful sounds improve action sensitivity regardless of timing. Experiments 7-9 addressed whether visual signal strength impacts audiovisual action perception, as predicted by the Principle of Inverse Effectiveness (PoIE). Results did not provide strong evidence for the PoIE, but rather showed that meaningful sounds can enhance perception of weak and strong visual signals alike. Experiment 10 explored how visual and motor experience impact audiovisual action perception. Collegiate athletes detected visual and audiovisual point-light actions with which they did and did not have extensive visual and motor experience. Results suggest that how action sounds impact visual sensitivity may relate to the typical action goals of the observer. Taken together, these experiments illustrate the importance of meaningful associations in the perception of audiovisual actions. Specifically, these results support the hypothesis that meaningful associations do not impact multisensory speech perception exclusively, but rather social perception more generally. Furthermore, they inform current theories of multisensory processing, as well as perception-action coupling theories of human motion perception.

ETD_4807

Ph.D.

Includes bibliographical references

Includes vita

by James Philip Thomas

http://hdl.rutgers.edu/1782.1/rucore10002600001.ETD.000068788

doi:10.7282/T3C53JG8

ETD doctoral

The author owns the copyright to this work.