The ability of the auditory system to analyze a sound into its component frequencies, frequency analysis or resolution, underlies many types of complex auditory perception. The purpose of this project will be to examine the development of this ability in the first year of infancy. Although some earlier work has addressed the issue, it is not clear how sensory and nonsensory factors contribute to the performance of infants in the tasks used to measure frequency resolution. In the proposed work, three psychoacoustic measures of frequency resolution, varying in susceptibility to nonsensory performance factors, will be obtained from three groups of infants, tested longitudinally at 3, 6 and 12 months of age. In the first experiment, the effects of increasing signal level of the infant's ability to discriminate frequencies will be tested in order to determine how age-related changes in absolute sensitivity might influence discrimination. In the second experiment, psychophysical tuning curves, a measure of frequency resolution requiring detection rather than discrimination, will be generated. This measure will allow for assessment of task effects on measures of frequency analysis and will also provide additional information about frequency selective response when the masker frequency is at some distance from that of the signal. However, since psychophysical tuning curve widths may be affected by response bias effects, a third experiment is proposed, in which detection thresholds for a tone masked by comb-filtered noise will be obtained. This measure, although not as informative as the psychophysical tuning curve, will provide a check against possible response bias effects.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS024525-02
Application #
3409208
Study Section
Hearing Research Study Section (HAR)
Project Start
1986-06-01
Project End
1987-11-30
Budget Start
1986-12-01
Budget End
1987-11-30
Support Year
2
Fiscal Year
1987
Total Cost
Indirect Cost
Name
University of Washington
Department
Type
Schools of Medicine
DUNS #
135646524
City
Seattle
State
WA
Country
United States
Zip Code
98195
Olsho, L W; Koch, E G; Carter, E A et al. (1988) Pure-tone sensitivity of human infants. J Acoust Soc Am 84:1316-24
Olsho, L W; Koch, E G; Halpin, C F (1987) Level and age effects in infant frequency discrimination. J Acoust Soc Am 82:454-64