Brain Size

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Human Uniqueness Compared to "Great Apes": 
Absolute Difference
MOCA Domain: 
Neuroscience
MOCA Topic Authors: 
Todd Preuss

Humans have the largest brains of any primate in absolute terms, as well as relative to body size. Brain size varies with body size - larger bodied species tend to have larger brains. The evolutionary increase in brain size in the hominin lineage, subsequent to the split between humans and chimpanzees, is well documented in the fossil record, with the greatest increase in the last 2 million years with the emergence of the genus Homo.

Timing

Timing of appearance of the difference in the Hominin Lineage as a defined date or a lineage separation event. The point in time associated with lineage separation events may change in the future as the scientific community agrees upon better time estimates. Lineage separation events are defined in 2017 as:

  • the Last Common Ancestor (LCA) of humans and old world monkeys was 25,000 - 30,000 thousand (25 - 30 million) years ago
  • the Last Common Ancestor (LCA) of humans and chimpanzees was 6,000 - 8,000 thousand (6 - 8 million) years ago
  • the emergence of the genus Homo was 2,000 thousand (2 million) years ago
  • the Last Common Ancestor (LCA) of humans and neanderthals was 500 thousand years ago
  • the common ancestor of modern humans was 100 - 300 thousand years ago

Possible Appearance: 
6,000 thousand years ago
Probable Appearance: 
2,500 thousand years ago
Definite Appearance: 
2,000 thousand years ago
Occurrence in Other Animals: 

 Encephalization—increases in brain size corrected for changes in body size—occurred independently in many vertebrate and mammalian groups (Jerison, 1973; Striedter, 2005).  Among mammals, some of the greatest increases in relative brain size occurred in the cetaceans—i.e., dolphins, porpoises, and other toothed whales (Marino et al., 2004).

Related MOCA Topics
Referenced By:
Topic Certainty
Adrenarche Speculative
Age of Fontanelles / Cranial Sutures Closure Likely
Cerebellar Volume Likely
CKB (Creatine kinase brain) Speculative
Corpus Callosum Size True
DUF1220 Domain Copy Number Likely
External Nose Projection Likely
Fatness at Birth Speculative
Foramen Magnum Placement Speculative
FZD8 (frizzled 8) Speculative
Global Pattern of Gene Expression in the Cortex Likely
HYDIN (Hydrocephalus inducing homolog) Speculative
Interneurons that Co-Express Parvalbumin and Calbindin Speculative
Long Term Memory Likely
Morphology of the Brow Ridge Speculative
NBPF15 (neuroblastoma breakpoint family, member 15) Likely
Nutritional Requirements During Different Life Stages
Occipital Bone Morphology Likely
Organized Gathering of Food Likely
Parental Investment
Rate of CNS Development
Sagittal Crest of the Skull Likely
Size of Sensory Thalamic Nuclei Likely
SLC6A8 (solute carrier family 6 (neurotransmitter transporter, creatine), member 8) Speculative
Small/Large Intestine Length Ratio Likely
SRGAP2 (SLIT-ROBO Rho GTPase activating protein 2) Speculative
Thyroid Hormone Metabolism Likely
Tool Making Likely
TTR (transthyretin)
Von Economo (Spindle) Cells Number and Size Likely
Whole Body Cooling Efficiency

References

  1. 3.3 million years of stone tool complexity suggests that cumulative culture began during the Middle Pleistocene, Paige, Jonathan, and Perreault Charles , Proceedings of the National Academy of Sciences, 2024/06/25, Volume 121, Issue 26, p.e2319175121, (2024)
  2. Evolutionary–developmental (evo-devo) dynamics of hominin brain size, González-Forero, Mauricio , Nature Human Behavior, 2024/05/27, (2024)
  3. Hominin brain size increase has emerged from within-species encephalization, Püschel, Thomas A., Nicholson Samuel L., Baker Joanna, Barton Robert A., and Venditti Chris , Proceedings of the National Academy of Sciences, 2024/11/26, Volume 121, Issue 49, (2024)
  4. Role of cell metabolism in the pathophysiology of brain size-associated neurodevelopmental disorders, Xing, Lei, Huttner Wieland B., and Namba Takashi , Neurobiology of Disease, 2024/09, Volume 199, p.106607, (2024)
  5. Temporal lobe evolution in Hominidae and the origin of human lobe proportions, Pearson, Alannah, and P. Polly David , American Journal of Biological Anthropology, 2024/10/03, Volume n/a, Issue n/a, p.e25027, (2024)
  6. Divergence-time estimates for hominins provide insight into encephalization and body mass trends in human evolution, Püschel, Hans P., Bertrand Ornella C., O’Reilly Joseph E., Bobe René, and Püschel Thomas A. , Nature Ecology and Evolution, 2021/04/01, (2021)
  7. The Driver of Extreme Human-Specific Olduvai Repeat Expansion Remains Highly Active in the Human Genome., Heft, Ilea E., Mostovoy Yulia, Levy-Sakin Michal, Ma Walfred, Stevens Aaron J., Pastor Steven, McCaffrey Jennifer, Boffelli Dario, Martin David I., Xiao Ming, et al. , Genetics, 2020 01, Volume 214, Issue 1, p.179-191, (2020)
  8. Human-specific ARHGAP11B induces hallmarks of neocortical expansion in developing ferret neocortex, Kalebic, Nereo, Gilardi Carlotta, Albert Mareike, Namba Takashi, Long Katherine R., Kostic Milos, Langen Barbara, and Huttner Wieland B. , eLife, 2018/11/28, Volume 7, p.e41241, (2018)
  9. Human-Specific NOTCH2NL Genes Expand Cortical Neurogenesis through Delta/Notch Regulation, Suzuki, Ikuo K., Gacquer David, Van Heurck Roxane, Kumar Devesh, Wojno Marta, Bilheu Angéline, Herpoel Adèle, Lambert Nelle, Cheron Julian, Polleux Franck, et al. , CellCell, 05/2018, Volume 173, Issue 6, p.1370 - 1384.e16, (2018)
  10. Pattern and process in hominin brain size evolution are scale-dependent, Du, Andrew, Zipkin Andrew M., Hatala Kevin G., Renner Elizabeth, Baker Jennifer L., Bianchi Serena, Bernal Kallista H., and Wood Bernard A. , Proceedings of the Royal Society B: Biological Sciences, 02/2018, Volume 285, Issue 1873, (2018)
  11. Body size, brain size, and sexual dimorphism in Homo naledi from the Dinaledi Chamber, Garvin, Heather M., Elliott Marina C., Delezene Lucas K., Hawks John, Churchill Steven E., Berger Lee R., and Holliday Trenton W. , J of Human Evol, 2017/10/01/, Volume 111, p.119 - 138, (2017)
  12. Neanderthal-Derived Genetic Variation Shapes Modern Human Cranium and Brain, Gregory, Michael D., J. Kippenhan Shane, Eisenberg Daniel P., Kohn Philip D., Dickinson Dwight, Mattay Venkata S., Chen Qiang, Weinberger Daniel R., Saad Ziad S., and Berman Karen F. , Nature Scientific Reports, 2017/07/24, Volume 7, Issue 1, p.6308, (2017)
  13. Primate brain size is predicted by diet but not sociality, DeCasien, Alex R., Williams Scott A., and Higham James P. , Nature Ecology & Evolution, 2017/03/27, Volume 1, p.0112 - , (2017)
  14. A single splice site mutation in human-specific ARHGAP11B causes basal progenitor amplification, Florio, Marta, Namba Takashi, Pääbo Svante, Hiller Michael, and Huttner Wieland B. , Science Advances, 2016/12/07, Volume 2, Issue 12, (2016)
  15. Evolution of brain and culture: the neurological and cognitive journey from Australopithecus to Albert Einstein., Falk, Dean , J Anthropol Sci, 2016 Jun 20, Volume 94, p.99-111, (2016)
  16. Evolution of Osteocrin as an activity-regulated factor in the primate brain, Ataman, Bulent, Boulting Gabriella L., Harmin David A., Yang Marty G., Baker-Salisbury Mollie, Yap Ee-Lynn, Malik Athar N., Mei Kevin, Rubin Alex A., Spiegel Ivo, et al. , Nature, 2016/11/10, Volume 539, Issue 7628, p.242 - 247, (2016)
  17. Fossil skulls reveal that blood flow rate to the brain increased faster than brain volume during human evolution, Seymour, Roger S., Bosiocic Vanya, and Snelling Edward P. , Royal Society Open Science, 2016/08/31, Volume 3, Issue 8, (2016)
  18. The Molecular Basis of Human Brain Evolution, Enard, Wolfgang , Current Biology, 2016/10/24, Volume 26, Issue 20, p.R1109 - R1117, (2016)
  19. A dual comparative approach: integrating lines of evidence from human evolutionary neuroanatomy and neurodevelopmental disorders., Hanson, Kari L., Hrvoj-Mihic Branka, and Semendeferi Katerina , Brain Behav Evol, 2014, Volume 84, Issue 2, p.135-55, (2014)
  20. Rapid evolution of the cerebellum in humans and other great apes., Barton, Robert A., and Venditti Chris , Curr Biol, 2014 Oct 20, Volume 24, Issue 20, p.2440-4, (2014)
  21. The human brain in numbers: a linearly scaled-up primate brain., Herculano-Houzel, Suzana , Front Hum Neurosci, 2009, Volume 3, p.31, (2009)
  22. Principles of Brain Evolution, Striedter, G. , Sunderland, Mass. , p.363, (2005)
  23. Origin and evolution of large brains in toothed whales, Marino, Lori, McShea Daniel W., and Uhen Mark D. , The Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology, Volume 281A, p.1247–1255, (2004)
  24. Evolution of the Brain and Intelligence, Jerison, Harry J. , New York, p.482, (1973)

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