It is generally recognized that simple harmonic ratios among partials promote their perceptual fusion. However, the influence of parallel gliding in log frequency upon fusion is not understood. The present experiment investigated fusion in relation to different types of parallel and non-parallel log-frequency motion of three concurrent tonal glides. The main hypothesis was that parallel motion on log-frequency-by-time coordinates favors fusion. It was reasoned that a higher degree of fusion of the glides evokes fewer auditory images. Fusion was thus measured by asking eighteen subjects to rate the number of distinct sounds perceived in various gliding stimuli. On test trials, subjects received a pair of stimuli in succession and had to judge which one contained more sounds and to rate the size of the difference on a 7-point scale. Each stimulus was a complex of three sinusoidal tones, gliding in frequency. Each 1400-ms three-glide complex was either increasing or decreasing in frequency, and the spacing among its components was either small, medium or large. The stimuli were aligned in one of five ways: (1) harmonically related, parallel, and therefore unequally spaced in log frequency, (2) inharmonic, parallel, and equally spaced in log frequency, (3) inharmonic, parallel, and unequally spaced in log frequency, (4) non-parallel and diverging in log frequency, and (5) non-parallel and converging in log frequency. Results showed that more sources were perceived under the three parallel conditions than under the two non-parallel ones (p $<$ 0.00001). Moreover, as the spacing between gliding partials increased, more distinct sounds were heard (p $<$ 0.00001). These results suggest that both spectral spacing and non-parallel log-frequency motion segregate concurrent glides. A multiple regression analysis showed that parallel log-frequency gliding promotes fusion over and above the contribution of average spectral spacing and harmonicity (p $<$.0001). The observed dat
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.26164 |
| Date | January 1994 |
| Creators | Turgeon, Martine |
| Contributors | Bregman, S. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Psychology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001420491, proquestno: MM94535, Theses scanned by UMI/ProQuest. |
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