Cited by 1,778Primate Behavior and EcologyNeurogenesis and neuroplasticity mechanismsMemory and Neural Mechanisms

The DOI matches its Crossref record; 75 of the 93 references it cites were found in a registry or an index; 11 of the 76 sources its claims cite were checked for support.

The human brain in numbers: a linearly scaled-up primate brain

Open access
Herculano-Houzel, Suzana·2009·Frontiers in Human Neuroscience

Abstract

The human brain has often been viewed as outstanding among mammalian brains: the most cognitively able, the largest-than-expected from body size, endowed with an overdeveloped cerebral cortex that represents over 80% of brain mass, and purportedly containing 100 billion neurons and 10x more glial cells. Such uniqueness was seemingly necessary to justify the superior cognitive abilities of humans over larger-brained mammals such as elephants and whales. However, our recent studies using a novel method to determine the cellular composition of the brain of humans and other primates as well as of rodents and insectivores show that, since different cellular scaling rules apply to the brains within these orders, brain size can no longer be considered a proxy for the number of neurons in the brain. These studies also showed that the human brain is not exceptional in its cellular composition, as it was found to contain as many neuronal and non-neuronal cells as would be expected of a primate brain of its size. Additionally, the so-called overdeveloped human cerebral cortex holds only 19% of all brain neurons, a fraction that is similar to that found in other mammals. In what regards absolute numbers of neurons, however, the human brain does have two advantages compared to other mammalian brains: compared to rodents, and probably to whales and elephants as well, it is built according to the very economical, space-saving scaling rules that apply to other primates; and, among economically built primate brains, it is the largest, hence containing the most neurons. These findings argue in favor of a view of cognitive abilities that is centered on absolute numbers of neurons, rather than on body size or encephalization, and call for a re-examination of several concepts related to the exceptionality of the human brain.

Overview

Integrity signals

Registry

Crossref · 10.3389/neuro.09.031.2009

Cites

75 of 75 references verified0 citation errors · 0 not checkable

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Nothing to recompute.

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Claims the paper makes

39 Own interpretation · 28 No full text of the sources · 13 Own result · 12 Not checked yet · 8 No basis given · 5 Partly supported · 5 Sources not found · 4 Supported · 1 Supported so far · accuracy not yet measured

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  • Probably not a substantial claim. 20
  • It may state two separate claims as one. 48
61 of 61
  • The paper relies on this without support.

    Humans are more cognitively capable than larger-brained mammals such as elephants and whales.

    “Such uniqueness was seemingly necessary to justify the superior cognitive abilities of humans over larger-brained mammals such as elephants and whales.”
  • The paper relies on this without support.

    Cognitive abilities can be meaningfully compared across species.

    “the higher cognitive and behavioral flexibility of monkeys over ungulates is anecdotally evident to any observer who compares the ingenious and complex abilities of macaques to those of cows or horses”
  • The paper relies on this without support.

    Non-neuronal cell densities are similar across species.

    “In view of the similar non-neuronal cell densities across species”
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Metadata

Authors
Herculano-Houzel, S.
Venue
Frontiers in Human Neuroscience
Published
2009
Volume
3
Pages
31-31
ISSN
1662-5161 (ISSN-L)
OpenAlex
W2005926822
Cited by
1,778
References
93
Citations by year
2026: 89 · 2025: 159 · 2024: 192 · 2023: 145 · 2022: 133 · 2021: 172 · 2020: 176 · 2019: 144 · 2018: 140 · 2017: 91 · 2016: 77 · 2015: 71 · 2014: 61 · 2013: 50 · 2012: 45
FWCI
33.51
Type
journal article
Language
en
Open access
Licence
cc-by
Locations
  • Frontiers in Human Neuroscience (publishedVersion, cc-by)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
  • Conselho Nacional de Desenvolvimento Científico e Tecnológico
  • Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro
Topics
  • Life Sciences › Agricultural and Biological Sciences › Ecology, Evolution, Behavior and Systematics › Primate Behavior and Ecology
  • Life Sciences › Neuroscience › Developmental Neuroscience › Neurogenesis and neuroplasticity mechanisms
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Memory and Neural Mechanisms
Keywords
human brain, primate brain, brain size, neuron number, glial cells, cerebral cortex, encephalization, cognitive ability, rodents, elephants, whales

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