title: Noise-Induced Frequency Modifications of Tamarin Vocalizations: Implications for Noise Compensation in Nonhuman Primates.
abstract: Previous research suggests that nonhuman primates have limited flexibility in the frequency content of their vocalizations, particularly when compared to human speech. Consistent with this notion, several nonhuman primate species have demonstrated noise-induced changes in call amplitude and duration, with no evidence of changes to spectral content. This experiment used broad- and narrow-band noise playbacks to investigate the vocal control of two call types produced by cotton-top tamarins (Saguinus Oedipus). In 'combination long calls' (CLCs), peak fundamental frequency and the distribution of energy between low and high frequency harmonics (spectral tilt) changed in response to increased noise amplitude and bandwidth. In chirps, peak and maximum components of the fundamental frequency increased with increasing noise level, with no changes to spectral tilt. Other modifications included the Lombard effect and increases in chirp duration. These results provide the first evidence for noise-induced frequency changes in nonhuman primate vocalizations and suggest that future investigations of vocal plasticity in primates should include spectral parameters.
authors.affiliation: Intercollege Graduate Degree Program in Ecology, Penn State University, University Park, PA, United States of America.
authors.forename: Cara F
authors.initials: CF
authors.lastname: Hotchkin
authors.affiliation: Department of Biology, Syracuse University, Syracuse, NY, United States of America.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Parks
authors.affiliation: Department of Psychology and Program in Linguistics, Penn State University, University Park, PA, United States of America.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Weiss
mesh_terms: D000161:Acoustic Stimulation; D000223:Adaptation, Psychological; D000818:Animals; D005260:Female; D008297:Male; D009622:Noise; D010470:Perceptual Masking; D012452:Saguinus / Q000502:physiology*; D013018:Sound Spectrography; D014828:Vocalization, Animal / Q000502:physiology*