Encephalization in Hominids: Evidence for the Model of Punctuationalism
Abstract
A progressive enlargement of the hominid brain started 3–2 million years ago, probably from a gracile australopithecine form. Since then, three major transitions in degree of encephalization have taken place, leading to modern Homo sapiens. In the present study it is shown that these transitions must have occurred in rapid bursts, interspersed with long periods of little or no evolutionary change (stasis). This stepwise mode of encephalization is in accordance with the model of punctuated evolutionary change. A further inquiry has been made into the size of the cerebral cortex of hominids and into the number of cortical neurons based on estimates which were derived from allometric equations in extant mammals.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
Given their similar brain sizes, humans and Neanderthals might both have needed a long overall maturation time.
“given their similar brain sizes160, humans and Neanderthals might both have needed a long overall maturation time161,162.”
From A catalog of single nucleotide changes distinguishing modern humans from archaic hominins (2019) · cites this paper as [160]
Cited by
Sorted by citations
Archaeology and cognitive evolution
Wynn, T. (2002) · Behavioral and Brain Sciences · doi:10.1017/s0140525x02000079 · Cited by 440 · see citing works
The brain of Homo habilis: A new level of organization in cerebral evolution
Tobias, P. V. (1987) · Journal of Human Evolution · doi:10.1016/0047-2484(87)90022-4 · Cited by 367 · see citing works
Brain Size, Cranial Morphology, Climate, and Time Machines [and Comments and Reply]
Beals, K. L., Smith, C. L., Dodd, S. M., Angel, J. L., Armstrong, E., Blumenberg, B., Girgis, F. G., Turkel, S., Gibson, K. R., Henneberg, M., et al. (1984) · Current Anthropology · doi:10.1086/203138 · Cited by 332 · see citing works
On the evolution and geometry of the brain in mammals
Hofman, M. A. (1989) · Progress in Neurobiology · doi:10.1016/0301-0082(89)90013-0 · Cited by 298 · see citing works
Self-citationEvolution of the Size and Functional Areas of the Human Brain
Schoenemann, P. T. (2006) · Annual Review of Anthropology · doi:10.1146/annurev.anthro.35.081705.123210 · Cited by 289 · see citing works
“First, as noted above, the brain is among the most metabolically expensive organs in the body [i.e., neural tissue has among the highest metabolic rates per gram (Aiello & Wheeler 1995, Hofman 1983b)].”
BackgroundBrain evolution inHomo:The “radiator” theory
Falk, D. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00078973 · Cited by 251 · see citing works
Arendt, T. (2003) · Progress in Neurobiology · doi:10.1016/j.pneurobio.2003.09.007 · Cited by 188 · see citing works
A shift toward birthing relatively large infants early in human evolution.
DeSilva, J. M. (2011) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.1003865108 · Cited by 177 · see citing works
“Hofman MA (1983) Encephalization in hominids: Evidence for the model of punctuationalism.”
BackgroundAlzheimer's disease as a disorder of mechanisms underlying structural brain self-organization
Arendt, T. (2001) · Neuroscience · doi:10.1016/s0306-4522(00)00516-9 · Cited by 168 · see citing works
Aspects of size and scaling in primate biology with special reference to the locomotor skeleton
Jungers, W. L. (1984) · American Journal of Physical Anthropology · doi:10.1002/ajpa.1330270505 · Cited by 140 · see citing works
COOK, N. (1984) · Brain and Language · doi:10.1016/0093-934x(84)90010-5 · Cited by 117 · see citing works
Tempo and mode in human evolution.
McHenry, H. M. (1994) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.91.15.6780 · Cited by 115 · see citing works
A catalog of single nucleotide changes distinguishing modern humans from archaic hominins
Kuhlwilm, M., & Boeckx, C. (2019) · Scientific Reports · doi:10.1038/s41598-019-44877-x · Cited by 108 · see citing works
“However, given their similar brain sizes (Hofman 1983), humans and Neanderthals might both have needed a long overall maturation time (Ponce de León et al. 2017; Rosas et al. 2017).”
BackgroundIntegrated phylogeny of the primate brain, with special reference to humans and their diseases
Rapoport, S. I. (1990) · Brain Research Reviews · doi:10.1016/0165-0173(90)90004-8 · Cited by 108 · see citing works
Striedter, G. F. (2004) · Elsevier eBooks · doi:10.1016/b978-012547626-3/50002-8 · Cited by 98 · see citing works
van Dongen, P. A. M. (1998) · Springer eBooks · doi:10.1007/978-3-642-18262-4_23 · Cited by 90 · see citing works
Arendt, T. (2000) · Neurobiology of Aging · doi:10.1016/s0197-4580(00)00216-5 · Cited by 89 · see citing works
Jungers, W. L. (1987) · Journal of Human Evolution · doi:10.1016/0047-2484(87)90072-8 · Cited by 87 · see citing works
The Bounded Brain: Toward Quantitative Neuroanatomy
Cherniak, C. (1990) · Journal of Cognitive Neuroscience · doi:10.1162/jocn.1990.2.1.58 · Cited by 81 · see citing works
Pattern and process in hominin brain size evolution are scale-dependent
Du, A., Zipkin, A. M., Hatala, K. G., Renner, E., Baker, J. L., Bianchi, S., Bernal, K. H., & Wood, B. A. (2018) · Proceedings of the Royal Society B Biological Sciences · doi:10.1098/rspb.2017.2738 · Cited by 70 · see citing works
Neurodegeneration and plasticity
Arendt, T. (2004) · International Journal of Developmental Neuroscience · doi:10.1016/j.ijdevneu.2004.07.007 · Cited by 69 · see citing works
“Most recently, it was shown that those neuronal systems playing a crucial role in ‘higher brain functions’ and thus becoming increasingly predominant as the evolutionary process of encephalization progresses, (Gorry, 1963; Hofman, 1983; Wachtler, 1982) such as hippocampus, neocortical association areas, and the cholin…”
BackgroundDisturbance of neuronal plasticity is a critical pathogenetic event in Alzheimer's disease
Arendt, T. (2001) · International Journal of Developmental Neuroscience · doi:10.1016/s0736-5748(01)00007-7 · Cited by 66 · see citing works
“Those neuronal systems play a crucial role in ‘higher brain functions’ and thus become increasingly predominant as the evolutionary process of encephalization progresses (Gorry, 1963; Wachtler, 1982; Hofman, 1983), such as hippocampus, neocortical association areas and the cholinergic basal forebrain neurons, also ret…”
BackgroundBody weight prediction in early fossil hominids: Towards a taxon‐“independent” approach
Hartwig‐Scherer, S. (1993) · American Journal of Physical Anthropology · doi:10.1002/ajpa.1330920103 · Cited by 66 · see citing works
Relative brain size, stratification, and social structure in anthropoids
Sawaguchi, T. (1990) · Primates · doi:10.1007/bf02380947 · Cited by 65 · see citing works
Hypothesis: Alzheimer's disease is a phylogenetic disease
Рапопорт, С. И. (1989) · Medical Hypotheses · doi:10.1016/0306-9877(89)90185-0 · Cited by 62 · see citing works
The causes of brain enlargement in human evolution
Foley, R. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079103 · Cited by 61 · see citing works
Begun, D. R., & Walker, A. (1993) · Springer eBooks · doi:10.1007/978-3-662-10382-1_14 · Cited by 54 · see citing works
Bertrand, O., & Silcox, M. T. (2016) · Journal of Vertebrate Paleontology · doi:10.1080/02724634.2016.1095762 · Cited by 51 · see citing works
“…encephalization, the cranial capacity or endocranial volume (mm3) was converted to brain mass (g) by dividing the endocranial volume by 1.05 (Hofman, 1983; Falk, 2007); the published EQs of apatemyids and plesiadapiforms had to be recalculated to be comparable to those calculated for I.…”
MethodInfluentialBertrand, O., Amador‐Mughal, F., & Silcox, M. T. (2016) · Journal of Anatomy · doi:10.1111/joa.12537 · Cited by 52 · see citing works
Virtual endocasts of fossil Sciuroidea: brain size reduction in the evolution of fossoriality
Bertrand, O., Amador‐Mughal, F., Lang, M. M., & Silcox, M. T. (2018) · Palaeontology · doi:10.1111/pala.12378 · Cited by 49 · see citing works
“Scale bar represents 10 mm. Colour online. cranial capacity or endocranial volume (mm3) was converted to brain mass (g) by dividing the endocranial volume by 1.05 (Hofman 1983; Falk 2007).”
MethodInfluentialEvolution of the Primate Brain
Falk, D. (2013) · Springer eBooks · doi:10.1007/978-3-642-27800-6_37-4 · Cited by 48 · see citing works
“Mean=1314 Hofman 1983 Neandertals ~0.07 -”
BackgroundInfluentialAllometric scaling in palaeontology: A critical survey
Hofman, M. A. (1988) · Human Evolution · doi:10.1007/bf02437441 · Cited by 48 · see citing works
Self-citationBertrand, O., Amador‐Mughal, F., & Silcox, M. T. (2016) · Proceedings of the Royal Society B Biological Sciences · doi:10.1098/rspb.2015.2316 · Cited by 44 · see citing works
Alzheimer’s disease as a disorder of dynamic brain self-organization
Arendt, T. (2004) · Progress in brain research · doi:10.1016/s0079-6123(04)47025-3 · Cited by 42 · see citing works
9 Evolution of the Primate Brain
Falk, D. (2007) · Springer eBooks · doi:10.1007/978-3-540-33761-4_37 · Cited by 40 · see citing works
Rapoport, S. I. (1999) · Brain Research Bulletin · doi:10.1016/s0361-9230(99)00095-7 · Cited by 39 · see citing works
Bertrand, O., Amador‐Mughal, F., Lang, M. M., et al. (2018) · Journal of Mammalian Evolution · doi:10.1007/s10914-017-9425-6 · Cited by 38 · see citing works
Alba, D. M. (2010) · PubMed · Cited by 37 · see citing works
Epigenesis and the evolution of the human brain
Aboitiz, F. (1988) · Medical Hypotheses · doi:10.1016/0306-9877(88)90047-3 · Cited by 34 · see citing works
On the presumed coevolution of brain size
Hofman, M. A. (1984) · Journal of Human Evolution · doi:10.1016/s0047-2484(84)80052-4 · Cited by 26 · see citing works
Self-citationHominin brain size increase has emerged from within-species encephalization
Püschel, T. A., Nicholson, S. L., Baker, J., Barton, R. A., & Venditti, C. (2024) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.2409542121 · Cited by 25 · see citing works
Evolution of the modern human brain
Beaudet, A., Du, A., & Wood, B. A. (2019) · Progress in brain research · doi:10.1016/bs.pbr.2019.01.004 · Cited by 22 · see citing works
Kunz, A., & Iliadis, C. (2007) · Child s Nervous System · doi:10.1007/s00381-007-0468-5 · Cited by 21 · see citing works
“The adaptation to the African savannas was a thermal stress, since 2.5 Ma, there was a major global cooling event, initiating climate change in East and South Africa [15, 20]; thus, the enlarged O/M sinus drainage system was a more efficient delivery of blood to vertebral venous plexus and without the need to be coole…”
BackgroundInfluentialHuman brains have shrunk: the questions are when and why
DeSilva, J. M., Fannin, L. D., Cheney, I., Claxton, A. G., Ilieş, I., Kittelberger, J., Stibel, J. M., & Traniello, J. F. A. (2023) · Frontiers in Ecology and Evolution · doi:10.3389/fevo.2023.1191274 · Cited by 21 · see citing works
“Converting this value to cc using the equations in Hofman (1983) and Ruff et al. (1997) yields an average of 1,350 cc.”
Smith, B. H. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079206 · Cited by 14 · see citing works
Neuroscience and Human Brain Evolution
Reyes, L. D., & Sherwood, C. C. (2014) · Springer series in bio-/neuroinformatics · doi:10.1007/978-3-319-08500-5_2 · Cited by 12 · see citing works
“…body size, however, cranial capacity in the hominin lineage has increased even more dramatically than is typical of other primates, indicating that brain size has expanded in hominins significantly more than expected based only on body size increase (Jerison 1973; Hofman 1983; Hawks et al. 2000).”
BackgroundArmstrong, E. (1990) · Elsevier eBooks · doi:10.1016/b978-0-12-547625-6.50006-4 · Cited by 21 · see citing works
Gutiérrez‐Ospina, G., Uribe‐Querol, E., Sánchez, N., Acuña, H. G., Padilla, P., & Hernández, E. (2004) · Brain Behavior and Evolution · doi:10.1159/000079116 · Cited by 12 · see citing works
“…Geovannini/Padilla/Hernández-Echeagaray Introduction In addition to the increase in thickness and surface area [Jerison, 1970, 1973; Martin, 1981; Hofman, 1983; Harvey and Bennett, 1983; Bugbee and Goldman-Rakic, 1983; Ebbesson, 1984; Bennett and Harvey, 1985; Haug, 1987; Radinsky, 1987;…”
BackgroundAbadías, N. M. (2007) · Cited by 11 · see citing works
Climate Change Predictive of Body Size and Proportionality in Humans
Stibel, J. M. (2023) · Evolutionary Biology · doi:10.1007/s11692-023-09616-1 · Cited by 13 · see citing works
Evolution of the Primate Brain
Falk, D. (2014) · Springer eBooks · doi:10.1007/978-3-642-39979-4_37 · Cited by 10 · see citing works
The role of a behavior in evolution
Bingham, G. P. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079000 · Cited by 10 · see citing works
Patre, P. L. D. (1991) · Medical Hypotheses · doi:10.1016/0306-9877(91)90187-4 · Cited by 10 · see citing works
Brain cooling via emissary veins: Fact or fancy?
Brengelmann, G. L. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079036 · Cited by 10 · see citing works
Evolution of a venous “radiator” for cooling cortex: “Prime releaser” of brain evolution inHomo
Falk, D. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079243 · Cited by 9 · see citing works
Rajki, K., Brehmer, W., Hammer, H.-J., Fischer, W. H., Daus, H., & Mauch, H. (1982) · Zentralblatt für Bakteriologie Mikrobiologie und Hygiene 1 Abt Originale A Medizinische Mikrobiologie Infektionskrankheiten und Parasitologie · doi:10.1016/s0174-3031(82)80108-x · Cited by 8 · see citing works
Aristotle redivivus? Multiple causes and effects in hominid brain evolution
Grüsser, O. ‐. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079115 · Cited by 7 · see citing works
The transmission of information in natural systems
Cook, N. D. (1984) · Journal of Theoretical Biology · doi:10.1016/s0022-5193(84)80039-9 · Cited by 6 · see citing works
Causes and consequences in the evolution of hominid brain size
Whiten, A. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x0007922x · Cited by 6 · see citing works
A Phylogenetic Hypothesis for Alzheimer’s Disease
Рапопорт, С. И. (1988) · Springer eBooks · doi:10.1007/978-3-642-73647-6_7 · Cited by 7 · see citing works
Hominin brain evolution, 1925–2011: an emerging overview
Falk, D. (2012) · Cambridge University Press eBooks · doi:10.1017/cbo9781139096164.011 · Cited by 5 · see citing works
Jerison, H. J. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079140 · Cited by 5 · see citing works
The radiator hypothesis: A theory in “vein”
Kimbel, W. H. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079152 · Cited by 4 · see citing works
Symmetry in knapped stones is real, not romanced
Humphrey, D. E. (2002) · Behavioral and Brain Sciences · doi:10.1017/s0140525x0229007x · Cited by 3 · see citing works
A proposal in relation to a genetic control of lifespan in mammals
Neill, D. (2010) · Ageing Research Reviews · doi:10.1016/j.arr.2010.05.004 · Cited by 3 · see citing works
The influence of thermoregulatory selection presures on hominid evolution
Wheeler, P. E. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079218 · Cited by 3 · see citing works
Holloway, R. L. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079139 · Cited by 3 · see citing works
Heat stress as a factor in the preadaptative approach to the origin of the human brain
Fiałkowski, K. R. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079085 · Cited by 3 · see citing works
Neural plasticity, heterochrony, and the onto-phylogeny of consciousness
Iurato, G. (2025) · Biosystems · doi:10.1016/j.biosystems.2025.105661 · Cited by 2 · see citing works
Upright posture and cranial hemodynamics in humans and other “tall” animals
Hargens, A. R., & Meyer, J. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079127 · Cited by 2 · see citing works
Master Mechanic, may I? Evolutionary permission versus evolutionary pressure
Finlay, B. L. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079097 · Cited by 2 · see citing works
Relating brains, blood, and bipedalism
Krantz, G. S. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079164 · Cited by 2 · see citing works
Brain evolution inHomo: the “hood” theory
Barton, R. A. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00078997 · Cited by 2 · see citing works
The multiple obstacles to encephalization
Abitbol, M. M. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00078985 · Cited by 2 · see citing works
On the possible evolution of brain cooling system inHomo:Sweating versus panting
Caputa, M. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079061 · Cited by 1 · see citing works
Dean, C. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079073 · Cited by 1 · see citing works
Zihlman, A. L. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079231 · Cited by 1 · see citing works
How did longevity promote brain expansion during primate evolution?
Рапопорт, С. И. (2003) · Springer eBooks · doi:10.1007/978-3-642-59356-7_5
Boiling over in the great rift valley
Scheibel, A. B. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079188
Selective brain cooling: A multidisciplinary concept
Brinnel, H. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079048
Beardedness, baldness, and northern climate
Cabanac, M. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x0007905x
Exercise as prime mover and a cool brain
Bortz, W. M. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079012
Overheated brains: Radiation of radiators?
Sénut, B. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x0007919x
Limber, J. E. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079176
The brain drain as a means of cooling hot heads
Brace, C. L. (1990) · Behavioral and Brain Sciences · doi:10.1017/s0140525x00079024
Meta-Neuroanatomy: The Myth of the Unbounded Mind/Brain
Cherniak, C. (1991) · Springer eBooks · doi:10.1007/978-94-011-3598-6_6
Langdon, J. H. (2022) · Springer texts in social sciences · doi:10.1007/978-3-031-14157-7_12
Thireau, M. (2015) · Hermann eBooks · doi:10.3917/herm.dupon.2015.01.0029
Diet and social factors selecting for increased encephalization in primates
DeCasien, A. R. (2025) · Evolution of Nervous Systems · doi:10.1016/b978-0-443-27380-3.00055-5
Neurotropic bornaviral pressure as a potential driver of mammalian encephalizationPreprint
Gauvain, E. (2025) · bioRxiv (Cold Spring Harbor Laboratory) · doi:10.64898/2025.12.02.691862
“When needed, endocranial volumes of rodents were converted to mass by dividing the volume by 1.05 54 .”
Influential
- Authors
- Hofman, M. A.
- Corresponding author
- Hofman, Michel A.
- ORCID
- Hofman, Michel A.
- Venue
- Brain, Behavior and Evolution
- Publisher
- S. Karger AG
- Published
- 2008-03-18
- Volume
- 22
- Issue
- 2-3
- Pages
- 102-117
- ISSN
- 0006-8977 (ISSN-L)
- 1421-9743
- OpenAlex
- W2091223598
- Cited by
- 90
- References
- 0
- Citations by year
- 2025: 3 · 2024: 1 · 2023: 2 · 2022: 1 · 2019: 2 · 2018: 3 · 2016: 3 · 2015: 1 · 2014: 2 · 2013: 1 · 2012: 1
- FWCI
- 6.48
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Brain Behavior and Evolution (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Social Sciences › Anthropology › Pleistocene-Era Hominins and Archaeology
- Social Sciences › Psychology › Social Psychology › Primate Behavior and Ecology
- Physical Sciences › Earth and Planetary Sciences › Paleontology › Evolution and Paleontology Studies
- Keywords
- encephalization, hominid brain evolution, punctuated evolution, brain size, australopithecines, human, allometric scaling, evolutionary stasis
- MeSH terms
- Haplorhini, Anthropometry, Body Weight, Brain, Cell Count, Cephalometry, Cerebral Cortex, Biological Evolution, Humans, Models, Genetic, Neurons, Organ Size, Paleontology
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
