Voicing judgements by chinchillas trained with a reward paradigm

Experiments were performed to replicate and extend previous findings of sim ilar categorization of voiced/voiceless consonant-vowel (CV) syllables by h umans and chinchillas. A reward paradigm was applied to the question of how stimulus rang affects the voice-onset-time (VOT) corresponding to the voic ed/voiceless category boundary. Each of four adult chinchillas and four hum an subjects identified synthetic CV syllables as voiced (/ba/, /da/, /ga/) or voiceless (/pa/, /ta/, ka/) using voiceless standards of either 80 or 12 0 ms. In both humans and animals, extending the VOT range from 80 to 120 ms shifted category boundaries to longer VOTs, but to a different extent acro ss listeners. Control experiments suggested that listeners were attending t o different phonetic cues in a manner that depended on the listener, rather than on species. The results are interpreted in terms of similar contextua l effects and use of multiple phonetic cues to voicing in humans and animal s. (C) 1999 Elsevier Science B.V. All rights reserved.