Dear Colleagues, I would like to draw your attention to the following paper, published in the January edition of the Journal of the Acoustical Society of America: Deecke, V.B. and Janik, V.M. 2006. Automated categorization of bioacoustic signals: Avoiding perceptual pitfalls. Journal of the Acoustical Society of America 119 (1): 645-653 ABSTRACT Dividing the acoustic repertoires of animals into biologically relevant categories presents a widespread problem in the study of animal sound communication, essential to any comparison of repertoires between contexts, individuals, populations, or species. Automated procedures allow rapid, repeatable, and objective categorization, but often perform poorly at detecting biologically meaningful sound classes. Arguably this is because many automated methods fail to address the nonlinearities of animal sound perception. We present a new method of categorization that incorporates dynamic time-warping and an adaptive resonance theory (ART) neural network. This method was tested on 104 randomly chosen whistle contours from four captive bottlenose dolphins (Tursiops truncatus), as well as 50 frequency contours extracted from calls of transient killer whales (Orcinus orca). The dolphin data included known biologically meaningful categories in the form of 42 stereotyped whistles produced when each individual was isolated from its group. The automated procedure correctly grouped all but two stereotyped whistles into separate categories, thus performing as well as human observers. The categorization of killer whale calls largely corresponded to visual and aural categorizations by other researchers. These results suggest that this methodology provides a repeatable and objective means of dividing bioacoustic signals into biologically meaningful categories. KEYWORDS Automated categorization, automated classification, killer whale, bottlenose dolphin, signature whistle, neural network, call recognition, repertoire size, dynamic time-warping Best regards Volker Deecke ============================================================== Volker Deecke, Ph.D. Marine Mammal Research Unit Cetacean Research Lab University of BC Vancouver Aquarium Marine Science Centre AERL Bldg., 2202 Main Mall P.O. Box 3232 Vancouver, BC, V6T 1Z4 Vancouver, BC V6B 3X8 Canada Canada Phone: +1.604.822.9150 +1.604.659.3429/3430 Fax: +1.604.822.8180 +1.604.659.3599 WWW: http://www.marinemammal.org/MMRU ==============================================================