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Comparative context of Plio-Pleistocene hominin brain evolution
1Department of Anthropology, Eliot College, University of Kent at Canterbury, Canterbury CT2 7NS, U.K. S.E.Elton@ukc.ac.uk
Journal of Human Evolution
|June 21, 2001
Summary
Brain size increased in Homo and Paranthropus boisei during the Plio-Pleistocene, but not in Theropithecus. This suggests hominin brain enlargement was specific to this group, despite shared environmental factors.
Area of Science:
- Paleoanthropology
- Primate Evolution
- Neuroscience
Background:
- Large brain size is a hallmark of Homo sapiens and some fossil hominins.
- Brain enlargement is a key evolutionary trend, but its drivers and exclusivity are debated.
Purpose of the Study:
- To investigate brain size changes in Plio-Pleistocene primates.
- To determine if brain enlargement was exclusive to hominins or a broader primate phenomenon.
Main Methods:
- Collected endocranial capacity data for Homo and Paranthropus from literature.
- Developed regression equations to estimate Theropithecus endocranial volume from external cranial dimensions.
- Analyzed temporal trends in brain size using nonparametric statistical tests.
Main Results:
- Endocranial volume showed an increasing temporal trend in Homo and Paranthropus boisei.
- No significant temporal trend in endocranial volume was observed for Theropithecus.
- Brain enlargement during the Plio-Pleistocene appears restricted to hominin lineages.
Conclusions:
- Hominin brain evolution, particularly in Homo and Paranthropus, involved significant size increases.
- Environmental, social, or dietary factors proposed to drive primate brain growth must account for its apparent restriction to hominins.
- Further research is needed to understand the specific selective pressures behind hominin brain enlargement.
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