Material composition discrimination of cylinders at different aspect angles by an echolocating Dolphin

Au, Whitlow W. L.; Turl, Charles W.

doi:10.1121/1.400930

Cited by 29 publications

(21 citation statements)

References 4 publications

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“…As noted earlier in Au and Turl's (1991) cylinder discrimination test, in some circumstances dolphins can recognize objects across different orientations even though echoes change dramatically when orientation changes. Variations of echoes from the same object presented at different orientations can be greater than variations of echoes produced from different objects (DeLong et al, 2006).…”

Section: Echoic Object Constancymentioning

confidence: 93%

“…In one experiment, a dolphin discriminated between cylinders, presented two at a time, that varied only in material (aluminum vs. stainless steel and aluminum vs. coral rock) (Au & Turl, 1991). Discrimination of the aluminum and coral rock cylinders was tested at novel orientations, and the dolphin continued to discriminate the stimuli.…”

Section: Echoic Object Discrimination: Echoic Cuesmentioning

confidence: 99%

“…To discriminate among objects, dolphins may use echo highlights via TSP (Au & Pawloski, 1989;Au & Turl, 1991). Dolphins appear to integrate information across click trains (e.g., Altes et al, 2003).…”

Section: General Conclusionmentioning

confidence: 99%

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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: Echoic Object Constancymentioning

confidence: 93%

Section: Echoic Object Discrimination: Echoic Cuesmentioning

confidence: 99%

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Echoic Object Recognition by the Bottlenose Dolphin

Harley¹,

DeLong²

2008

CCBR

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“…In a number of previous studies, experimenters have presented echolocating dolphins with discrimination tasks and then examined the echoes from the objects used in those tasks with simulated dolphin sonar signals ͑e.g., Au and Martin, 1988;Au and Pawloski, 1992;Au and Turl, 1991;Hammer and Au, 1980;Nachtigall et al, 1980͒. An inspection of the object echoes allowed the experimenters to speculate about the echo features the dolphins may have used to discriminate between the objects.…”

Section: Introductionmentioning

confidence: 99%

Acoustic features of objects matched by an echolocating bottlenose dolphin

DeLong

Lemonds

et al. 2006

The Journal of the Acoustical Society of America

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The focus of this study was to investigate how dolphins use acoustic features in returning echolocation signals to discriminate among objects. An echolocating dolphin performed a match-to-sample task with objects that varied in size, shape, material, and texture. After the task was completed, the features of the object echoes were measured (e.g., target strength, peak frequency). The dolphin's error patterns were examined in conjunction with the between-object variation in acoustic features to identify the acoustic features that the dolphin used to discriminate among the objects. The present study explored two hypotheses regarding the way dolphins use acoustic information in echoes: (1) use of a single feature, or (2) use of a linear combination of multiple features. The results suggested that dolphins do not use a single feature across all object sets or a linear combination of six echo features. Five features appeared to be important to the dolphin on four or more sets: the echo spectrum shape, the pattern of changes in target strength and number of highlights as a function of object orientation, and peak and center frequency. These data suggest that dolphins use multiple features and integrate information across echoes from a range of object orientations.

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“…The experiment was similar to other object constancy studies with dolphins (Au & Turl, 1991;Nachtigall et al, 1980), except that the objects varied along multiple traits instead of a single trait. The participants were presented with echo sequences from three objects that varied in size, shape, and material.…”

Section: Introductionmentioning

confidence: 50%

Recognizing objects from multiple orientations using dolphin echoes

DeLong¹,

Heberle²,

Mata³

et al. 2013

Proceedings of Meetings on Acoustics

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Object constancy, the ability to recognize objects despite changes in orientation, has not been well studied in the auditory modality. Dolphins use echolocation for object recognition, and objects ensonified by dolphins produce echoes that can vary significantly as a function of orientation. In four experiments, human listeners had to classify echoes from objects ensonified with dolphin signals. Participants were trained to discriminate among the objects using an 18-echo stimulus from a 10 degree range of aspect angles, then tested with novel aspect angles across a 60 degree range. In the first two experiments the three objects varied in material, size, and shape. Participants were typically successful recognizing the objects at all angles (M = 78%). In Experiment 3, the three objects had the same material but different shapes. Participants were often unsuccessful recognizing the objects at all angles (M = 46%). In Experiment 4, participants had to classify echoes from four fish species across a wider range of angles (330 degrees). Preliminary results show overall poor performance (M = 45%). These results suggest that object characteristics play a role in whether performance is more view-dependent or view-invariant. These studies can provide insight into the process dolphins use to identify objects.

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Material composition discrimination of cylinders at different aspect angles by an echolocating Dolphin

Cited by 29 publications

References 4 publications

Echoic Object Recognition by the Bottlenose Dolphin

Echoic Object Recognition by the Bottlenose Dolphin

Acoustic features of objects matched by an echolocating bottlenose dolphin

Recognizing objects from multiple orientations using dolphin echoes

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