Left hemispheric advantage for numerical abilities in the bottlenose dolphin

Kilian, Annette; Fersen, Lorenzo von; Güntürkün, Onur

doi:10.1016/j.beproc.2004.11.003

Cited by 42 publications

(31 citation statements)

References 23 publications

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“…Visual analyses in bottlenose dolphins showed a general superiority of the right visual field (left hemisphere) for visual stimuli discrimination and for visual spatial tasks [13]–[16]. In accordance with these findings, Killian [17] reported a right-visual field advantage for discriminating relational dimensions between stimuli differing in numerosity in a two-choice discrimination paradigm. More recently, the influence of familiarity on the preferential use of one eye to look at human visual stimuli were tested in five captive dolphins and results showed that, at group level, dolphins preferentially use their left eye to look at both familiar and unfamiliar humans [18].…”

Section: Introductionsupporting

confidence: 70%

Visual Lateralization in Wild Striped Dolphins (Stenella coeruleoalba) in Response to Stimuli with Different Degrees of Familiarity

et al. 2012

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BackgroundApart from findings on both functional and motor asymmetries in captive aquatic mammals, only few studies have focused on lateralized behaviour of these species in the wild.Methodology/Principal FindingsIn this study we focused on lateralized visual behaviour by presenting wild striped dolphins with objects of different degrees of familiarity (fish, ball, toy). Surveys were conducted in the Gulf of Taranto, the northern Ionian Sea portion delimited by the Italian regions of Calabria, Basilicata and Apulia. After sighting striped dolphins from a research vessel, different stimuli were presented in a random order by a telescopic bar connected to the prow of the boat. The preferential use of the right/left monocular viewing during inspection of the stimuli was analysed.ConclusionResults clearly showed a monocular viewing preference with respect to the type of the stimulus employed. Due to the complete decussation of the optical nerves in dolphin brain our results reflected a different specialization of brain hemispheres for visual scanning processes confirming that in this species different stimuli evoked different patterns of eye use. A preferential use of the right eye (left hemisphere) during visual inspection of unfamiliar targets was observed supporting the hypothesis that, in dolphins, the organization of the functional neural structures which reflected cerebral asymmetries for visual object recognition could have been subjected to a deviation from the evolutionary line of most terrestrial vertebrates.

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Section: Introductionsupporting

confidence: 70%

Visual Lateralization in Wild Striped Dolphins (Stenella coeruleoalba) in Response to Stimuli with Different Degrees of Familiarity

et al. 2012

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“…Indeed, most of the comparative literature investigated numerical abilities of vertebrates by using relative numerosity judgments (e.g., which array has more? Kilian et al, 2005; Beran, 2006; Miletto Petrazzini et al, 2015) or, to some extent, absolute numerosity categorizations (e.g., which array has three items? Nieder et al, 2002; Ditz and Nieder, 2015).…”

Section: Discussionmentioning

confidence: 99%

How Illusory Is the Solitaire Illusion? Assessing the Degree of Misperception of Numerosity in Adult Humans

2016

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The Solitaire illusion occurs when the spatial arrangement of items influences the subjective estimation of their quantity. Unlike other illusory phenomena frequently reported in humans and often also in non-human animals, evidence of the Solitaire illusion in species other than humans remains weak. However, before concluding that this perceptual bias affects quantity judgments differently in human and non-human animals, further investigations on the strength of the Solitaire illusion is required. To date, no study has assessed the exact misperception of numerosity generated by the Solitaire arrangement, and the possibility exists that the numerical effects generated by the illusion are too subtle to be detected by non-human animals. The present study investigated the strength of this illusion in adult humans. In a relative numerosity task, participants were required to select which array contained more blue items in the presence of two arrays made of identical blue and yellow items. Participants perceived the Solitaire illusion as predicted, overestimating the Solitaire array with centrally clustered blue items as more numerous than the Solitaire array with blue items on the perimeter. Their performance in the presence of the Solitaire array was similar to that observed in control trials with numerical ratios larger than 0.67, suggesting that the illusory array produces a substantial overestimation of the number of blue items in one array relative to the other. This aspect was more directly investigated in a numerosity identification task in which participants were required to estimate the number of blue items when single arrays were presented one at a time. In the presence of the Solitaire array, participants slightly overestimated the number of items when they were centrally located while they underestimated the number of items when those items were located on the perimeter. Items located on the perimeter were perceived to be 76% as numerous as centrally located items. The magnitude of misperception of numerosity reported here may represent a useful tool to help to understand whether non-human animals have different perceptual mechanisms or, instead, do not display adequate numerical abilities to spot the illusory difference generated in the Solitaire array.

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“…It could perhaps be argued that the putative right eye advantage for the captive bottlenose dolphins in visual processing, discussed earlier, might be involved, in this case, for surveillance of the edge of the pool. Siniscalchi et al (2012) have even argued that "the right-side down bias" in gray whales (Kasuya & Rice, 1970) humpback whales (Clapham et al, 1995) and bottlenose dolphin fish beaching (Hoese, 1971;Rigley et al, 1981;Silber & Fertl, 1995) could all be the result of the right eye/left hemisphere bias reported by Kilian et al (2005) and other studies referred to earlier, including their own. This may be possible under good viewing conditions, such as exist for swimming in a pool or for surface feeding in clear water.…”

Section: Comparison Of Marine Mammal and Human Asymmetriesmentioning

confidence: 93%

“…Tasks included various tests of visual‐pattern discrimination including numerosity perception, tasks involving visual‐auditory associations, and a task involving swimming through three different hoops in succession in a variety of orders. Kilian et al () conclude that these studies “suggest an overall superiority of dolphins for visual processing” involving the right eye/left hemisphere (p. 183) which contrasts with the well‐known human right hemisphere visuospatial specialization, and the right hemisphere specialization for global versus local stimulus processing (see MacNeilage et al, ).…”

Section: Asymmetrical Behavior In Marine Mammalsmentioning

confidence: 99%

“…Other eye use preferences have also been observed and they are germane to the overall question of marine mammal asymmetries, even though they do not directly involve action. A number of studies by Güntürkün's research group have shown a right‐eye advantage in bottlenose dolphins for various vision‐related tasks (e.g., Kilian, von Fersen, & Güntürkün, ). Tasks included various tests of visual‐pattern discrimination including numerosity perception, tasks involving visual‐auditory associations, and a task involving swimming through three different hoops in succession in a variety of orders.…”

Section: Asymmetrical Behavior In Marine Mammalsmentioning

confidence: 99%

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Vertebrate whole‐body‐action asymmetries and the evolution of right handedness: A comparison between humans and marine mammals

MacNeilage

2013

Developmental Psychobiology

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As part of a vertebrate-wide trend toward left brain/right side asymmetries in routine whole-body actions, marine mammals show signs of rightward appendage-use biases, and short- and long-term turning asymmetries most of which are unique in non-humans in being just as strong as right handedness, and even stronger than human handedness-related turning biases. Short-term marine mammal turning asymmetries and human about-turning asymmetries share a leading right side, suggesting a commonality in left hemisphere intentional control. The long-term leftward turning bias that both groups share may be an indirect result of both sensory and motor influences on the right side in dolphins, but be induced by a right-hemisphere-controlled spatial/attentional bias to the left in humans. Marine mammals may share, with humans and other higher primates, a left hemisphere specialization for action dynamics, although evidence is currently lacking for human-like right hemisphere specializations relevant to action in other vertebrates.

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Left hemispheric advantage for numerical abilities in the bottlenose dolphin

Cited by 42 publications

References 23 publications

Visual Lateralization in Wild Striped Dolphins (Stenella coeruleoalba) in Response to Stimuli with Different Degrees of Familiarity

Visual Lateralization in Wild Striped Dolphins (Stenella coeruleoalba) in Response to Stimuli with Different Degrees of Familiarity

How Illusory Is the Solitaire Illusion? Assessing the Degree of Misperception of Numerosity in Adult Humans

Vertebrate whole‐body‐action asymmetries and the evolution of right handedness: A comparison between humans and marine mammals

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