Three studies of comodulation masking release.

Format:

Book

Thesis/Dissertation

Author/Creator:

Buss, Emily.

Contributor:

Richards, Virginia M., advisor.

University of Pennsylvania.

Language:

English

Subjects (All):

Psychometrics.

Audiology.

0300.

0632.

Penn dissertations--Psychology.

Psychology--Penn dissertations.

Local Subjects:

Penn dissertations--Psychology.

Psychology--Penn dissertations.

0300.

0632.

Physical Description:

83 pages

Contained In:

Dissertation Abstracts International 57-11B.

System Details:

Mode of access: World Wide Web.

text file

Summary:

Thresholds for detecting a pure tone signal masked by a coherently amplitude modulated masker (a comodulated masker) which extends beyond the critical band centered on the signal are generally lower than for the case of a narrow masker centered on the signal that does not extend beyond the critical band centered on the signal or the case of an unmodulated masker. This phenomenon is called comodulation masking release (CMR). Three experiments were carried out to examine various aspects of this CMR. Experiment One explored the role of auditory object formation (e.g., grouping) in CMR. In contrast with previous findings, grouping manipulations did not alter the magnitude of the CMR for maskers overlapping in frequency. Experiment Two attempted to discriminate between two basic classes of models of CMR, one based on on-going envelope comparisons across frequency and the other on the use of masker envelopes distant from the signal to cue times of improved signal-to-noise ratio at the signal frequency. Data support a cued listening model where modulation minima of maskers distant from the signal trigger sampling at the output of the auditory filter centered on the signal frequency. Experiment Three used a limited set of reproducible noise maskers to examine particular aspects of randomly modulated stimuli that might dictate the pattern of thresholds obtained. Thresholds were consistent with several single-channel models, as well as one of the across-frequency comparison models tested. The results from these three experiments, taken together, suggest that: (1) cues to grouping do not place a role in CMR when the masker bands are overlapping in frequency, (2) thresholds for detecting a pure tone masked by a comodulated masker are consistent with some form of obligatory cued listening, and (3) thresholds for detecting a pure tone masked by a randomly modulated masker are influenced by both within and between channel cues.

Notes:

Thesis (Ph.D. in Psychology) -- University of Pennsylvania, 1996.

Source: Dissertation Abstracts International, Volume: 57-11, Section: B, page: 7270.

Supervisor: Virginia M. Richards.

Local Notes:

School code: 0175.

ISBN:

9780591204674

Access Restriction:

Restricted for use by site license.