Echoic Object Recognition by the Bottlenose Dolphin

Harley, Heidi E.; DeLong, Caroline M.

doi:10.3819/ccbr.2008.30003

Cited by 20 publications

(19 citation statements)

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“…Cetaceans recognize echolocated objects as images similar to visual objects. One can even say that they 'see' objects through echolocation, perceiving a complex echoic-visual image (Herman & Pack, 1992;Pack & Herman, 1995;Harley, Roitblat & Nachtigall, 1996;Herman, Pack & Hoffmann-Kuhnt, 1998;Harley & DeLong, 2008). Note that an echolocation act itself provides single-dimensional information, but echolocating cetaceans were shown to be able to recognize three-dimensional images at different orientations, 'using a multidimensional representation containing amplitude and spectral information' (Helweg et al, 1996).…”

Section: Can Internal Organs Serve For Visual Display?mentioning

confidence: 99%

‘Antlers inside’: are the skull structures of beaked whales (Cetacea: Ziphiidae) used for echoic imaging and visual display?

Gol’din

2014

Biol J Linn Soc Lond

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Skulls of many living and extinct beaked whales (Ziphiidae) contain various bizarre bone and tooth structures. Many of them show sexual dimorphism in their skull anatomy: males have bizarre skull structures, whereas females do not. Opinions differ as to what the function of these structures might be. Some believe that these are weapons; others, that they are sound transmitters. This article argues that these structures are the means of visual display. Many of the bizarre bone structures of beaked whales are not exposed like ‘visuals’ of terrestrial tetrapods, but are located deep in soft tissues. Nevertheless, toothed whales recognize objects (including three‐dimensional bodies), using echolocation. So, along with visual means, they can ‘see’ and ‘show’ their internal bone structures with echoic imaging and use them as informational sources in social interactions and in individual or species recognition. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 510–515.

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Section: Can Internal Organs Serve For Visual Display?mentioning

confidence: 99%

‘Antlers inside’: are the skull structures of beaked whales (Cetacea: Ziphiidae) used for echoic imaging and visual display?

Gol’din

2014

Biol J Linn Soc Lond

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“…The dolphin represents a special case in the analysis of visual object recognition because vision is not the only sense it brings to bear on the task of recognizing objects at a distance. Vision and echolocation are complementary senses that work together to form an integrated representation of the world (Harley & DeLong, 2008; Harley et al, 1996) and, because dolphins often navigate visually opaque environments, vision is likely to be secondary to echolocation. Interestingly, some of the same aspects of object recognition that present challenges in the visual domain are similar in the echoic domain, in that when objects are rotated in space, they result in strikingly different proximal sensory inputs.…”

Section: Discussionmentioning

confidence: 99%

“…Dolphins echolocate by emitting a series of broadband clicks and listening to the returning echoes (Au, 1993). Dolphins extract information about objects from acoustic features of echoes (Harley & DeLong, 2008). Most of the objects dolphins encounter are aspect-dependent, meaning that the size and shape of the surfaces of the object will change as they are ensonified from different orientations.…”

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confidence: 99%

Visual perception in a bottlenose dolphin (Tursiops truncatus): Successful recognition of 2-D objects rotated in the picture and depth planes.

DeLong

Fellner

Wilcox

et al. 2020

Journal of Comparative Psychology

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Aquatic species such as bottlenose dolphins can move in 3 dimensions and frequently view objects from different orientations. This study examined their ability to identify 2-D objects visually despite changes in orientation across 2 rotation planes. A dolphin performed a matching-to-sample task in which a sample was presented at a different orientation from its match in a 3-alternative choice array. Samples were presented at 6 aspect angles in the picture plane (0°, ±45°, ±135°, 180°) and 6 aspect angles in the depth plane (0°, −45°, ±90°, +135°, 180°). Alternatives were always presented at 0°. Performance was significantly better than chance for all aspect angles in both rotation plane tests. There was a significant linear decline in accuracy as the sample object was rotated from 0° toward 180° in the picture plane. Performance with familiar objects (M = 97.1%) exceeded performance with novel objects (M = 76.9%). In the depth plane rotation test, there was a significant quadratic trend in accuracy as the sample object was rotated from 0° toward 180°, in which performance was significantly lower at ±90° than at all other orientations. Performance in the picture plane where all object features were available irrespective of orientation was significantly better than performance in the depth plane where the availability of visible features were dependent upon orientation (M = 81.2% vs. M = 63.0%). The dolphin’s performance in this study shows evidence of both viewpoint-independent and viewpoint-dependent processes.

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“…Flexibility is also required to identify objects using echolocation alone in that the echoes from different aspects of a single object can vary more than those between different objects (review in Harley and DeLong, 2008). For objects that vary only in size, like different-sized disks, dolphins can use differences in amplitude to discriminate among the disks.…”

Section: Cetaceansmentioning

confidence: 99%

The Relevance of Ecological Transitions to Intelligence in Marine Mammals

2020

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Macphail's comparative approach to intelligence focused on associative processes, an orientation inconsistent with more multifaceted lay and scientific understandings of the term. His ultimate emphasis on associative processes indicated few differences in intelligence among vertebrates. We explore options more attuned to common definitions by considering intelligence in terms of richness of representations of the world, the interconnectivity of those representations, the ability to flexibly change those connections, and knowledge. We focus on marine mammals, represented by the amphibious pinnipeds and the aquatic cetaceans and sirenians, as animals that transitioned from a terrestrial existence to an aquatic one, experiencing major changes in ecological pressures. They adapted with morphological transformations related to streamlining the body, physiological changes in respiration and thermoregulation, and sensory/perceptual changes, including echolocation capabilities and diminished olfaction in many cetaceans, both in-air and underwater visual focus, and enhanced senses of touch in pinnipeds and sirenians. Having a terrestrial foundation on which aquatic capacities were overlaid likely affected their cognitive abilities, especially as a new reliance on sound and touch, and the need to surface to breath changed their interactions with the world. Vocal and behavioral observational learning capabilities in the wild and in laboratory experiments suggest versatility in group coordination. Empirical reports on aspects of intelligent behavior like problem-solving, spatial learning, and concept learning by various species of cetaceans and pinnipeds suggest rich cognitive abilities. The high energy demands of the brain suggest that brain-intelligence relationships might be fruitful areas for study when specific hypotheses are considered, e.g., brain mapping indicates hypertrophy of specific sensory areas in marine mammals. Modern neuroimaging techniques provide ways to study neural connectivity, and the patterns of connections between sensory, motor, and other cortical regions provide a biological framework for exploring how animals represent and flexibly use information in navigating and learning about their environment. At this stage of marine mammal research, it would still be prudent to follow Macphail's caution that it is premature to make strong comparative statements without more empirical evidence, but an approach that includes learning more about how animals flexibly link information across multiple representations could be a productive way of comparing species by allowing them to use their specific strengths within comparative tasks.

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Echoic Object Recognition by the Bottlenose Dolphin

Cited by 20 publications

References 50 publications

‘Antlers inside’: are the skull structures of beaked whales (Cetacea: Ziphiidae) used for echoic imaging and visual display?

‘Antlers inside’: are the skull structures of beaked whales (Cetacea: Ziphiidae) used for echoic imaging and visual display?

Visual perception in a bottlenose dolphin (Tursiops truncatus): Successful recognition of 2-D objects rotated in the picture and depth planes.

The Relevance of Ecological Transitions to Intelligence in Marine Mammals

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