Dooling, R.J., Brown, S.D., Nespor, A. and Hawks, J.W. (1989). Perception of vowels by budgerigars (Melopsittacus undulatus). J. Acoust. Soc. Am. 86, S80.

Budgerigars (parakeets) were trained using operant conditioning techniques to respond to differences between speech stimuli. Response latencies were used to construct similarity matrices and multidimensional scaling procedures were then used to produce perceptual (spatial) maps of these stimuli. For natural vowel tokens, budgerigars showed evidence of perceiving phonetic categories in spite of variation in talkers including talker gender and talker age. Experiments with synthetic vowel tokens generally confirmed and extended these findings. Multiple regression techniques revealed that the perceptual dimensions obtained from MDS were highly correlated with the frequencies of the first and second formants. These results suggest that both natural and synthetic vowels are probably perceived in similar ways by budgerigars and humans. These results have relevance for theories of speech perception and language development in humans. [Work supported by NIH.]