Multiple acoustic features underlie vocal signal recognition in tamarins: antiphonal calling experiments.

We examine which acoustic features are relevant for recognition of the cotton-top tamarin (Saguinus oedipus) combination long-call. This vocalization, emitted by both males and females, functions in maintaining group cohesion, territory defense and mate attraction. Using the tamarins' natural antiphonal vocal response to hearing a combination long-call as the primary measure of recognition, we presented subjects with synthetic exemplars of combination long-calls in which we manipulated across one of three acoustic dimensions: frequency, time and amplitude. Results indicated that although acoustic features in the frequency and time domains are important for combination long-call recognition, the changes in amplitude within and between syllables are not. Furthermore, while the fundamental frequency appears to be the used to encode information about the frequency contour, the temporal information is derived from the harmonics. Overall, these results suggest that tamarins use a specific suite of acoustic features for combination long-call recognition.