The object behind the echo: dolphins (Tursiops truncatus) perceive object shape globally through echolocation

Pack, Adam A.; Herman, Louis M.; Hoffmann‐Kuhnt, Matthias; Branstetter, Brian K.

doi:10.1016/s0376-6357(01)00200-5

Cited by 42 publications

(38 citation statements)

References 23 publications

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“…Pack, Herman, and their associates (Herman, Pack, & Hoffmann-Kuhnt, 1998;Pack & Herman, 1995;Pack, Herman, Hoffmann-Kuhnt, & Branstetter, 2002) have conducted several cross-modal matching tasks with a sub-adult female dolphin, Elele. The dolphin was trained to match objects intra-modally (sample and choices both presented only visually or only echoically) and cross-modally (visual samples to echoic alternatives; echoic samples to visual alternatives).…”

Section: Extraction Of Object Features Through Echolocationmentioning

confidence: 99%

Echoic Object Recognition by the Bottlenose Dolphin

Harley¹,

DeLong²

2008

CCBR

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Object recognition, essential to many animals, often occurs underwater and in poor visibility conditions for bottlenose dolphins. Bottlenose dolphins can use sound through their ability to echolocate in order to recognize objects. Echoic object recognition is an unusual faculty that offers rich research opportunities and is the focus of this article. This review begins with a brief overview of the dolphin's echolocation system followed by considerations of echoic object discrimination, echoic object constancy, the use of echo trains versus individual echoes for object recognition, and extraction of object feature information from echoes. The authors present new data relating the acoustic analysis of objects with a dolphin's ability to recognize those objects. The results highlight the potential uses for simultaneous analysis of acoustic and behavioral data in order to understand better which features of echoes and echo trains allow the dolphin to recognize objects across vision and echolocation.

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Section: Extraction Of Object Features Through Echolocationmentioning

confidence: 99%

Echoic Object Recognition by the Bottlenose Dolphin

Harley¹,

DeLong²

2008

CCBR

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“…Furthermore, bottlenose dolphins can spontaneously (i.e., on the first trial) match complexly shaped objects across the senses of vision and echolocation (Pack et al 2002;Herman et al 1998;Pack & Herman 1995). Since light and sound are not physically correlated, these authors have argued that the observed cross-modal matching ability was based on the direct perception of the spatial structure or the shape of the object.…”

Section: Horizontal Angular Discrimination By An Echolocating Bottlenmentioning

confidence: 99%

HORIZONTAL ANGULAR DISCRIMINATION BY AN ECHOLOCATING BOTTLENOSE DOLPHINTURSIOPS TRUNCATUS

et al. 2003

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A bottlenose dolphin was tested on its ability to echoically discriminate horizontal angular differences between two arrays of vertical, air-filled, PVC rods. The blindfolded dolphin was required to station in a submerged, vertically-oriented hoop, 2 radial metres from the stimuli, and indicate whether an array with four rods (S+) was to the left or the right of an array with two rods (S-), by pressing a corresponding paddle. The angular separation between the rods within each array (6w) was maintained at 2 degrees but the angular separation between the two arrays (6h) was varied to produce angular differences (b.6 = eb-ew) ranging from 0.25 degrees to 4 degrees. A modified method of constant stimuli was used to test for angular discrimination ability, and yielded a psychometric function having a 75% correct threshold of 1.6 degrees. This threshold fell between the passive listening minimum audible angle thresholds of 0.9 degrees for click signals and 2.1 degrees for a pure tone signal (Renaud & Popper 1975). Analyses of response times, number of clicks and inter-click intervals failed to detect any significant adaptive behaviour occurring as the task became more difficult. These results help to define angular resolution capabilities of dolphin sonar that may play an important role in representing spatial information in the dolphin's environment.

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“…Dolphins have an acute ability to echoically discriminate between targets that vary along the dimensions of size ͑Ayrapet 'yants et al, 1969;Au and Pawloski, 1992͒, material composition ͑Nachtigall, 1980͒, and shape ͑Helweg et al, 1996Pack et al, 2002͒. During echolocation, dolphins typically emit a series of "clicks" where the inter-click interval is sufficient for the dolphin to receive an echo before emitting a consecutive click.…”

Section: Introductionmentioning

confidence: 99%

Representing multiple discrimination cues in a computational model of the bottlenose dolphin auditory system

Branstetter¹,

Mercado

Au³

2007

The Journal of the Acoustical Society of America

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A computational model of the dolphin auditory system was developed to describe how multiple discrimination cues may be represented and employed during echolocation discrimination tasks. The model consisted of a bank of gammatone filters followed by half-wave rectification and low pass filtering. The output of the model resembles a spectrogram; however, the model reflects temporal and spectral resolving properties of the dolphin auditory system. Model outputs were organized to represent discrimination cues related to spectral, temporal and intensity information. Two empirical experiments, a phase discrimination experiment [Johnson et al., Animal Sonar Processes and Performance (Plenum, New York, 1988)] and a cylinder wall thickness discrimination tasks [Au and Pawolski, J. Comp. Physiol. A 170, 41-47 (1992)] were then simulated. Model performance was compared to dolphin performance. Although multiple discrimination cues were potentially available to the dolphin, simulation results suggest temporal information was used in the former experiment and spectral information in the latter. This model's representation of sound provides a more accurate approximation to what the dolphin may be hearing compared to conventional spectrograms, time-amplitude, or spectral representations.

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The object behind the echo: dolphins (Tursiops truncatus) perceive object shape globally through echolocation

Cited by 42 publications

References 23 publications

Echoic Object Recognition by the Bottlenose Dolphin

Echoic Object Recognition by the Bottlenose Dolphin

HORIZONTAL ANGULAR DISCRIMINATION BY AN ECHOLOCATING BOTTLENOSE DOLPHINTURSIOPS TRUNCATUS

Representing multiple discrimination cues in a computational model of the bottlenose dolphin auditory system

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