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Sound localization of frequency-modulated sinusoids by Old World monkeys
The Journal of the Acoustical Society of America
|September 1, 1986
Summary
The minimum audible angle (MAA) in monkeys shows that frequency range, not sweep rate, is key for directional hearing. This finding helps understand auditory spatial perception in non-human primates.
Area of Science:
- Auditory Neuroscience
- Animal Behavior
Background:
- Directional hearing is crucial for survival and communication.
- The minimum audible angle (MAA) quantifies directional hearing acuity.
- Understanding MAA in non-human primates offers insights into auditory processing evolution.
Purpose of the Study:
- To measure the minimum audible angle (MAA) in Old World monkeys (Macaca radiata).
- To investigate the influence of frequency sweeps (range and rate) on MAA.
- To identify potential cues for frequency modulated (FM) sound localization.
Main Methods:
- MAA was measured in four Macaca radiata using linear frequency sweeps.
- Stimuli included varying frequency ranges (0.5–1.3 kHz) and sweep rates (100–200 ms).
- Comparisons were made between upsweeps, downsweeps, and variations in sweep rate and frequency range.
Main Results:
- MAA decreased with increased frequency range and sweep rate in specific upsweeps.
- Frequency range, rather than sweep rate, was found to be the primary determinant of MAA.
- Interaural phase differences at higher frequencies were considered as potential FM localization cues.
Conclusions:
- Frequency range significantly impacts directional hearing acuity in Macaca radiata.
- Auditory spatial perception in these monkeys is influenced by the extent of frequency changes.
- Interaural phase differences may serve as important cues for localizing FM sounds.
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