Reviewhybrid2001

Variation in hominid brain size: How much is due to method?

89 citations0/0 files storedHOMO

No readable copy stored yet — this record is metadata only.

Pleistocene-Era Hominins and Archaeology Forensic Anthropology and Bioarchaeology Studies Morphological variations and asymmetry

Abstract

Brain size represented by cranial capacity (CC) is one of the most frequently analysed characters of hominids. Accuracy of individual CC estimates depends on completeness of specimens and methods used for reconstruction and measurement. A file of published estimates of CC of hominids dated from 3.2 Ma (million years) to 10 Ka (thousand years) including 606 estimates for 243 specimens was compiled. In the file, 75 specimens are available with multiple values (3 to 15) obtained by various methods and/or by various authors. Using individuals as classes in ANOVA, intraclass variation, which represents "error" of estimates, was calculated. For the total sample of multiple estimates (N = 382) the error variance is 5315 ml2. The error standard deviation is 73 ml (coefficient of variation (CV = 7.3%), quite large in comparison to the actual variation in CC in modern humans, SD = 157 ml (CV = 11.6%). This large error makes us wonder whether any fossil can be reliably placed with respect to a particular "cerebral Rubicon" between palaeospecies. Recent discussions concerning cranial capacity of Stw505 are a case in point regarding errors in CC estimation. In actual repeated 30 time measurements on a research quality cast we obtained with various methods (water, seeds, plasticine) CC estimates ranging from 484 to 586 ml. The range of estimates in the literature is from 515 to 625 ml. When hominid CC by taxon with date as a covariate is subjected to ANOVA, taxon is responsible for 5% of the variance while date is responsible for the main portion, (89%). The relationship between CC and date is best characterised as a gradual time trend. It is proven by the ANOVA test for linearity, by gamma test for trend and by ASReml fitting of a linear function. The line of best fit to this time trend is a double exponential curve which explains 90% of the total variance in CC: CC = 306.63 (4.83(0.9995)DATE) Essentially the same curve fits subsamples of CC dated at less than 1 Ma and at 3.2-1.0 Ma. This has several implications for the nature of the Darwinian process to be reconstructed.

Citations in this library

Stored only when both papers are in the corpus — 89 citations exist upstream.

References

1995The Expensive-Tissue Hypothesis: The Brain and the Digestive System in Human and Primate Evolution 1975EVOLUTION OF THE BRAIN AND INTELLIGENCE 2017Evolutionary History of the Robust Australopithecines 1997Body mass and encephalization in Pleistocene Homo 2002An Introduction to Human Evolutionary Anatomy 2000Earliest Pleistocene Hominid Cranial Remains from Dmanisi, Republic of Georgia: Taxonomy, Geological Setting, and Age 1863Evidence as to Man's Place in Nature 1992Body size and proportions in early hominids

Cited by

2009Fundamental Dimensions of Environmental Risk 2006Evolution of the Size and Functional Areas of the Human Brain 2012Bridging the bonding gap: the transition from primates to humans 2013New insights into differences in brain organization between Neanderthals and anatomically modern humans 2016Early Evidence for Brilliant Ritualized Display: Specularite Use in the Northern Cape (South Africa) between ∼500 and ∼300 Ka 2005STONE TOOLS AND THE UNIQUENESS OF HUMAN CULTURE

Imported from OpenAlex (CC0) — nothing here is generated.