Cognitive hierarchy of acoustic power spectrum features for simulated biosonar target echoes in the bottlenose dolphin (Tursiops truncatus)

• Published in: The Journal of the Acoustical Society of America 2019-10, Vol.146 (4), p.2745-2745
• Main Authors: Accomando, Alyssa W., Mulsow, Jason, Houser, Dorian S., Finneran, James J.
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.5136504

Previous work with bottlenose dolphins [Dubrovsky et al., “Mechanisms of signal discrimination and identification in the auditory system of Tursiops truncatus,” in Marine Mammal Sensory Systems, edited by Thomas et al. (Plenum, New York, 1992), pp. 235–240] suggested that the perception of coarse envelopes of echo power spectra (“macrostructure”) is hierarchically dominant to finer-scale spectral features (“microstructure”). In the present study, two dolphins passively listened to and discriminated between two standard click doublets having different micro- and macrostructure. The dolphins were provided food reinforcement for remaining on an underwater station after the “negative” stimulus (two clicks with 100-μs separation) and for touching a paddle after the “positive” stimulus (two clicks with 150-μs separation). The dolphins were then presented with probe stimuli that were hybrids of the two standard stimuli. Each probe had a macrostructure identical to the positive or negative stimulus but the microstructure of the alternate standard. Preliminary results show the dolphins responding to probes in a manner consistent with macrostructure supremacy. This is in line with previous work suggesting that the macrostructure is hierarchically dominant over microstructure. [Work supported by the Office of Naval Research.]