Browsing by Subject "Pitch"
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Item Effects of timing and context on pitch comparisons between spectrally segregated tones.(2011-12) Borchert, Elizabeth Marta OlsenPitch, the perceptual correlate of fundamental frequency (F0), is an important cue for understanding aspects of both music and speech. Much research has been devoted to pitch, with most being dedicated to measuring listeners' ability to judge pitch differences between sounds that are otherwise identical. However, in the natural environment, pitch comparisons are often made between different speech sounds (or different musical instruments), which differ not only in pitch but also in timbre. This dissertation investigates factors that affect normal-hearing listeners' ability to perceive and discriminate pitches of tones that differ in timbre due to being filtered into segregated spectral regions. The first study shows that the timing of tone presentation affects discrimination ability: listeners have difficulties comparing the F0s of sequentially presented sounds, and are much better able to perform the task when the tones are presented simultaneously. A follow-up experiment reveals that rather than explicitly comparing F0s, listeners seem to use a perceptual fusion cue when the tones are presented simultaneously; performance worsens when perceptual fusion is disrupted by asynchronous presentation or by auditory stream segregation induced with captor tones. A further study reveals that listeners' difficulty comparing sequentially presented tones of different timbres persists despite intensive training, and that individual differences in sequential tone discrimination cannot be reliably predicted based on musical experience or on analytical versus synthetic listening mode. Since pitch comparisons often occur within a musical context, the remainder of the thesis investigates the effect of a musical context on sequential pitch discrimination. Regardless of the predictability of the brief context, pitch discrimination generally improves for targets presented following a melodic context that establishes a tonal center corresponding to the pitch of the target tone. This effect of tonality is stronger for discrimination of different-timbre tone pairs than for same-timbre tone pairs. One interpretation of these findings is that sequential different-timbre pitch discrimination is limited more by cognitive factors, which are influenced by tonal context, than is same-timbre discrimination. The interactions between pitch, timbre, and context described in this thesis provide challenges for our understanding of how we perceive pitch in complex listening situations.Item FASER Flight 01(2011-09-08) Taylor, BrianItem FASER Flight 02(2011-09-08) Taylor, BrianItem FASER Flight 03(2011-12-06) Taylor, BrianItem FASER Flight 04(2011-12-06) Taylor, BrianItem GPS FASER Flight 01(2014-09-04) Taylor, BrianItem GPS FASER Flight 02(2011-11-17) Taylor, BrianItem Ibis Flight 20(2013-12-12) Taylor, BrianItem Ibis Flight 23(2013-12-12) Taylor, BrianItem Mechanisms for Coding Pitch(2018-05) Whiteford, KellyPitch, the perceptual correlate of a sound’s frequency, is a fundamental attribute in speech and melody perception. We utilized individual differences across listeners with normal and disordered hearing to better understand how pitch is represented in the auditory system. Results from young, normal hearing listeners and listeners varying in age suggested the bulk of variability in sensitivity to modulations in frequency (FM) and amplitude (AM) likely reflects central, rather than peripheral, limitations. For listeners varying in degree of sensorineural hearing loss, however, sensitivity to FM was directly related to the fidelity of tonotopic (place) coding within the cochlea. This was contrary to the widely accepted understanding that FM is represented by precise, phase-locked spike times in the auditory nerve. To test the role of central processes on pitch perception, several experiments were conducted on listeners with congenital amusia, a neurogenetic disorder characterized by poor fine-grained pitch perception, unrelated to peripheral coding. We found that amusic deficits extend beyond poor pitch discrimination, including poor discrimination for high frequencies as well as poor detection for FM and AM tones. Despite the long-held understanding that amusia is a life-long deficit for pitch and music, impervious to training, we found rapid learning for pitch and melody discrimination in amusia. The learning effects were large and maintained for at least one-year. Overall, the findings suggest peripheral place coding is important for the fidelity of pitch, but many processes beyond the periphery can also contribute to variability in pitch perception.Item Thor Flight 20(2011-07-26) Taylor, BrianItem Thor Flight 22(2011-07-26) Taylor, BrianItem Thor Flight 26(2011-10-11) Taylor, BrianItem Thor Flight 46(2012-05-21) Taylor, BrianItem Thor Flight 47(2012-06-22) Taylor, BrianItem Thor Flight 78(2012-10-30) Taylor, Brian