The Laboratory of Comparative Psychoacoustics
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Department of Psychology University of Maryland at College Park College Park, MD 20742 |
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The Laboratory of Comparative Psychoacoustics
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Department of Psychology University of Maryland at College Park College Park, MD 20742 |
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EDUCATION
2002 Ph.D. Psychology, University of Maryland College Park - Development of auditory sensitivity in budgerigars
1993 M.S. Psychology, University of Maryland College Park - Perception of developing vocalizations in the budgerigar
1991 B.S. Psychology, University of Maryland College Park
CURRENT EMPLOYMENT
Research Assistant Professor, Laboratory of Comparative Psychoacoustics, Department of Psychology, University of Maryland
PDF of my complete CV
PUBLISHED PAPERS
Dooling, R. J., Brown, S. D., Manabe, K. & Powell, E. F. (1996). The perceptual foundations of vocal learning in budgerigars. In Moss, C. F. & Shettleworth, S. (Eds.) Neuroethological studies of cognitive and perceptual processes, Westview Press.
Brittan-Powell, E. F., Dooling, R. J. & Farabaugh, S. M. (1997). Vocal development in the budgerigar (Melopsittacus undulatus): Contact call learning. Journal of Comparative Psychology, 111, 226-241.
Higgs, D.M., D. Soares, E.F. Brittan-Powell, M.J. Souza, C.E. Carr, R.J. Dooling, & A.N. Popper. (2002). Amphibious auditory responses of the American Alligator (Alligator mississippiensis). J. Comp. Physiol. A., 188, 217-223.
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AUDITORY BRAINSTEM RESPONSES IN BUDGERIGARS
Auditory feedback influences the development of budgerigar vocalizations, but until now, little was known about nestling hearing. Through two studies, I tracked the development of auditory sensitivity in nestling budgerigars using the auditory brain stem response (ABR).
In the first experiment, the ABR was recorded in adult budgerigars in response to clicks and tones. The typical budgerigar ABR waveform showed two prominent peaks occurring within 4 ms of the stimulus onset. As sound pressure levels increased, ABR peak latency decreased, and peak amplitude increased for all waves while interwave interval remained relatively constant. While ABR thresholds were higher than behavioral thresholds, the shape of the budgerigar ABR-derived audiogram closely paralleled that of the behavioral audiogram. Based on the ABR, budgerigars hear best between 1 and 5.7 kHz with best sensitivity at 2.86 kHz - the frequency corresponding to the peak frequency in budgerigar vocalizations. The latency of ABR peaks increased and amplitude decreased with increasing repetition rate, and the latency increase was greater for wave. Generally, changes in the ABR were comparable to what has been found in other vertebrates.
Brittan-Powell, E. F., Dooling, R.J. and Gleich, O. (2002). Auditory brainstem responses (ABR) in adult budgerigars (Melopsittacus undulatus). Journal of the Acoustical Society of America, 112, 999-1008.
In the second experiment, ABRs were used to track the development of auditory sensitivity in nestling budgerigars from 5 days post hatch (P5) until P43. With 95-100 dB being the highest level available, responses could be obtained from nestlings as young as P7 but only at frequencies at or below 2 kHz. Thresholds for these frequencies were above 90 dB SPL but improved noticeably over the next 6 days. By P12, responses could be obtained for frequencies up to 4.8 kHz, with best sensitivity at 2 kHz. By P30, ABR responses could be elicited to all frequencies tested, with the shape of the ABR audiogram becoming adult-like. The average ABR audiogram was indistinguishable from that of adult budgerigars by P30. This series of experiments shows that non-invasive ABRs can be used to assess peripheral auditory system function, including thresholds, in adult and nestling budgerigars. This is the first complete study of hearing development in a bird that uses auditory feedback to learn and modify their vocalizations throughout life.
Brittan-Powell, E. F. and Dooling, R.J. (2004). Development of Auditory Sensitivity in budgerigars (Melopsittacus undulatus), Journal of the Acoustical Society of America, 115, 3092-3102.
VOCAL DEVELOPMENT IN BUDGERIGARS
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Budgerigars have a complex vocal repertoire, some of which develops through learning. The course of development in budgerigars from hatching to about 4 weeks postfledging (approx. 85 days of age) has been examined. Food-begging calls show changes in duration, peak frequency, bandwidth, and frequency modulation with age. Within a week of fledging, each bird produces a contact call bearing a strong resemblance to a shortened version of its patterned food-begging call. By 4 weeks postfledging, budgerigar contact call repertoires often contain more than one call type, and there is clear evidence of sharing and imitation among calls of parents, fledglings, and other social companions. These results suggest parallels with certain aspects of language development in humans.
Brittan-Powell, E. F., Dooling, R. J. & Farabaugh, S. M. (1997). Vocal development in the budgerigar (Melopsittacus undulatus): Contact call learning. Journal of Comparative Psychology, 111, 226-241.
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