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ABSTRACT: When attending to a tone at a given frequency, listeners are most sensitive to that tone and others within a restricted band of frequencies surrounding it. This region of enhanced sensitivity defines the attention band that was measured in two experiments using a modified version of the probe-signal method of Greenberg and Larkin [J. Acoust. Soc. Am. 44, 1513-1523 (1968)]. Experiment 1 showed that at five center frequencies, from 0.25 to 4.0 kHz, the shape of the attention band resembles that of the auditory filter as inferred from notched-noise masking experiments by other investigators. The width of the attention band is close to the critical band at higher frequencies, but only half as wide at 0.25 and 0.5 kHz. Experiment 2 produced psychometric functions for unattended probe tones at least 0.23 kHz away from a fully attended, 1-kHz target tone. From these functions, the effective attenuation, measured as the threshold difference between the 1-kHz target and the probes, was estimated to be 7 dB; the amount of attenuation appeared to be about the same regardless of how far the probe frequency was from the attended band. One interpretation of these results is that bands centered on the unattended tones contribute to the decision process with some small but measurable weight and are not entirely ignored.
The Journal of the Acoustical Society of America 07/1991; 89(6):2837-42. · 1.55 Impact Factor
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ABSTRACT: The onset-time difference delta T required to lateralize a 30-ms bifrequency tone burst toward the leading ear was measured as a function of the frequency difference delta F between the tone in the left ear and the tone in the right ear. At center frequencies of 0.5 and 4 kHz, four normal listeners tested at 80 and 100 dB SPL had delta Ts that were relatively constant at subcritical delta Fs, but increased at delta Fs wider than a critical band. At 1 kHz, delta T increased with delta F even at subcritical delta Fs. Ten listeners with cochlear impairments were tested at 100 dB SPL. Seven had normal delta Ts at 4 kHz, despite hearing losses between 50 and 70 dB. At 0.5 and 1 kHz, mildly impaired listeners had nearly normal lateralization functions, whereas more severely imparied listeners had very large delta Ts and no frequency selectivity. These and other findings indicate that listeners even with moderate to severe hearing losses can lateralize normally on the basis of interaural differences in onset envelope, but not on the basis of temporal differences in the fine structure.
The Journal of the Acoustical Society of America 08/1984; 76(1):77-86. · 1.55 Impact Factor
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ABSTRACT: This study compares frequency selectivity--as measured by four different methods--in observers with normal hearing and in observers with conductive (nonotosclerotic), otosclerotic, noise-induced, or degenerative hearing losses. Each category of loss was represented by a group of 7 to 10 observers, who were tested at center frequencies of 500 Hz and 4000 Hz. For each group, the following four measurements were made: psychoacoustical tuning curves, narrow-band masking, two-tone masking, and loudness summation. Results showed that (a) frequency selectivity was reduced at frequencies where a cochlear hearing loss was present, (b) frequency selectivity was reduced regardless of the test level at which normally-hearing observers and observers with cochlear impairment were compared, (c) all four measures of frequency selectivity were significantly correlated and (d) reduced frequency selectivity was positively correlated with the amount of cochlear hearing loss.
Journal of speech and hearing research 10/1980; 23(3):646-69.
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ABSTRACT: A new and powerful procedure for determining frequency analysis in the auditory system, as evidence by the critical band, is described. The onset time difference, delta T, needed to lateralize 30-msec tone bursts toward the leading ear was measured as a function of the frequency difference, delta F, between the brust in one ear and the burst in the other ear. When delta F was less than the critical band, threshold delta T was constant at 100 mu sec or less, depending on center frequency; beyond the critical band, delta T increased with delta F. These dichotically measured critical bandwidths increased from 110 Hz at a center frequency of 500 Hz to 1100 Hz at a center frequency of 6000 Hz. They were unaffected by varying signal level from 25 to 80 dB or signal duration from 10 to 300 msec. The sam e critical-band values have been measured with monaural stimuli in loudness summation, maskin, detection, phase perception, consonance, and so forth.
Sensory processes 01/1977; 1(2):109-26.
