Questioning the interpretations of behavioral observations of cetaceans: Is there really support for a special intellectual status for this mammalian order?

Manger, Paul R.

doi:10.1016/j.neuroscience.2013.07.041

Cited by 45 publications

(41 citation statements)

References 194 publications

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“…Apes are reported to have thicker axons than other mammals, and for fibres connecting cortical and subcortical areas in the brain, velocities of 10 m s 21 are reported, while peripheral nerves (e.g. the sciatic nerve) may reach 150 m s 21 . On the other hand, the axons of cetaceans (whales and dolphins) and elephants have thin myelin sheaths and consequently relatively low conduction velocities [28,42,43].…”

Section: The Cortex As a Dominant Contributor To The 'Seat' Of Intellmentioning

confidence: 97%

Neuronal factors determining high intelligence

Dicke¹,

Roth²

2016

Phil. Trans. R. Soc. B

146

107

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One contribution of 16 to a discussion meeting issue 'Homology and convergence in nervous system evolution'. Many attempts have been made to correlate degrees of both animal and human intelligence with brain properties. With respect to mammals, a much-discussed trait concerns absolute and relative brain size, either uncorrected or corrected for body size. However, the correlation of both with degrees of intelligence yields large inconsistencies, because although they are regarded as the most intelligent mammals, monkeys and apes, including humans, have neither the absolutely nor the relatively largest brains. The best fit between brain traits and degrees of intelligence among mammals is reached by a combination of the number of cortical neurons, neuron packing density, interneuronal distance and axonal conduction velocity-factors that determine general information processing capacity (IPC), as reflected by general intelligence. The highest IPC is found in humans, followed by the great apes, Old World and New World monkeys. The IPC of cetaceans and elephants is much lower because of a thin cortex, low neuron packing density and low axonal conduction velocity. By contrast, corvid and psittacid birds have very small and densely packed pallial neurons and relatively many neurons, which, despite very small brain volumes, might explain their high intelligence. The evolution of a syntactical and grammatical language in humans most probably has served as an additional intelligence amplifier, which may have happened in songbirds and psittacids in a convergent manner.

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Section: The Cortex As a Dominant Contributor To The 'Seat' Of Intellmentioning

confidence: 97%

Neuronal factors determining high intelligence

Dicke¹,

Roth²

2016

Phil. Trans. R. Soc. B

146

107

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“…The fact that a greater proportion of cetacean's cerebral cortex when compared to great apes and other mammals of similar brain sizes is occupied by white matter rather than by gray matter (where neuronal computation occurs), and particularly an unfavourable combination of high interneuronal distance plus low axonal conduction velocity has lead to the scientific judgement that cetacean's brains have less computational power [2,98,99]. Further it has lead to the belief that there is not a single behavioral achievement that has not also been shown in several other species [18,20]. This has increased the reluctance of one part of the scientific community to believe that cetaceans' large brain is related to intelligence or any special intellectual capacities.…”

Section: Discussionmentioning

confidence: 99%

“…The large size of the cetacean brain and their reported behaviors have been popularly accepted as being indicative of high levels of intelligence. However, from the scientific community's viewpoint, the interpretation of behavioral observations in cetaceans and especially whether there is real support (or not) for a special intellectual status for this mammalian order has generated a substantial amount of controversy [2,[18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Is Cetacean Intelligence Special? New Perspectives on the Debate

Chinea

2017

Entropy

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Abstract:In recent years, the interpretation of our observations of animal behaviour, in particular that of cetaceans, has captured a substantial amount of attention in the scientific community. The traditional view that supports a special intellectual status for this mammalian order has fallen under significant scrutiny, in large part due to problems of how to define and test the cognitive performance of animals. This paper presents evidence supporting complex cognition in cetaceans obtained using the recently developed intelligence and embodiment hypothesis. This hypothesis is based on evolutionary neuroscience and postulates the existence of a common information-processing principle associated with nervous systems that evolved naturally and serves as the foundation from which intelligence can emerge. This theoretical framework explaining animal intelligence in neural computational terms is supported using a new mathematical model. Two pathways leading to higher levels of intelligence in animals are identified, each reflecting a trade-off either in energetic requirements or the number of neurons used. A description of the evolutionary pathway that led to increased cognitive capacities in cetacean brains is detailed and evidence supporting complex cognition in cetaceans is presented. This paper also provides an interpretation of the adaptive function of cetacean neuronal traits.

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“…Although dolphins are able to distinguish between objects differing in shape, they are incapable of categorization, for example of distinguishing between 'round' and 'triangular' objects and assigning an unfamiliar round or triangular object to one of these two categories-something that pigeons, crows, parrots, dogs, any kind of primates and even bees are capable of [87].…”

Section: Brains and Intelligence In Elephants And Cetaceansmentioning

confidence: 99%

Convergent evolution of complex brains and high intelligence

Roth

2015

Phil. Trans. R. Soc. B

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One contribution of 16 to a discussion meeting issue 'Origin and evolution of the nervous system'. Within the animal kingdom, complex brains and high intelligence have evolved several to many times independently, e.g. among ecdysozoans in some groups of insects (e.g. blattoid, dipteran, hymenopteran taxa), among lophotrochozoans in octopodid molluscs, among vertebrates in teleosts (e.g. cichlids), corvid and psittacid birds, and cetaceans, elephants and primates. High levels of intelligence are invariantly bound to multimodal centres such as the mushroom bodies in insects, the vertical lobe in octopodids, the pallium in birds and the cerebral cortex in primates, all of which contain highly ordered associative neuronal networks. The driving forces for high intelligence may vary among the mentioned taxa, e.g. needs for spatial learning and foraging strategies in insects and cephalopods, for social learning in cichlids, instrumental learning and spatial orientation in birds and social as well as instrumental learning in primates.

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Questioning the interpretations of behavioral observations of cetaceans: Is there really support for a special intellectual status for this mammalian order?

Cited by 45 publications

References 194 publications

Neuronal factors determining high intelligence

Neuronal factors determining high intelligence

Is Cetacean Intelligence Special? New Perspectives on the Debate

Convergent evolution of complex brains and high intelligence

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