ASA 124th Meeting New Orleans 1992 October

5aSP3. Labeling of the voiceless affricate/fricative contrast and an analogous nonspeech continuum by hooded rats.

Peter Howell

Philip Reed

Dept. of Psychol., Univ. College London, London WC 1E, England

Stuart Rosen

Univ. College London, London WC 1E, England

The voiceless affricate/fricative contrast has played an important role in auditory theories of speech perception. This type of theory draws its support from, among others, experimental data on animals. However, nothing is known about differential responding of affricate/fricative continua by animals. Preliminary results were obtained regarding the ability of hooded rats to ``label'' affricate--fricative and an analogous nonspeech continua where the nonspeech continuum was created by randomly flipping the polarity of each sample in the digitized speech waveforms with a probability 1/2. The rats were trained on the endpoints of a ``cha''--``sha''continuum (using positive reinforcement in a two-level choice experiment) cued by covariations in rise time and frication duration (0--80 ms rise time). Differential labeling was similar to humans. The animals were switched to the nonspeech continuum without further training. Once again, performance was similar to humans. The implications for auditory theories are discussed. [Work supported by MRC and CRF.]