Discrimination of phase altered targets by an echolocating Atlantic bottlenose dolphin.
Sensitivity of echolocating dolphins to phase changes within echoes may be a vital piece of information when constructing echolocation models. Previous experiments have yielded ambiguous results leaving it unclear what cues might have been used by passively listening dolphins to discriminate between different phase altered signals. This study used a phantom echo generator to produce computer controlled echoes. The dolphin interacted with the system in a real echolocation task to discriminate between simulated targets that were unaltered and those that had a 180° phase shift. The frequency amplitude spectral content between the two targets was the same. There were no temporal differences between the two targets. The only cue that the dolphin could use to discriminate between them was the 180° phase shift. The dolphin preformed at a success level of 40% in discriminating the two echoes. This indicates that the 180° phase shift was not perceived.
University of California San Diego, Serf Building Room 295 0435, 9500 Gilman Drive, La Jolla, California 92093, USA. sibsen@ucsd.edu
Stuart D
SD
Ibsen
Mark W
MW
Muller
Whitlow W L
WW
Au
Paul E
PE
Nachtigall
Marlee
M
Breese
D000161:Acoustic Stimulation; D000818:Animals; D001307:Auditory Perception; D050681:Bottle-Nosed Dolphin / Q000502:physiology*; D003463:Cues; D004192:Discrimination, Psychological; D004455:Echolocation; D005260:Female; D017603:Signal Detection, Psychological; D013018:Sound Spectrography; D013997:Time Factors