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The Ādam Paradox Hypothesis 32
Strand One: The Hardware — Brains as Structure
Big Brains, Early in the Record
Cranial capacity is one of the most obvious features in human evolution. Our
closest relatives, the chimpanzees, average ~400 cc. Neanderthals averaged
~1,500–1,600 cc — sometimes larger than us. Early Homo sapiens, from Omo
(~195 ka) and Herto (~160 ka), fall comfortably within the modern range
(~1,350–1,500 cc) (Rightmire, 2004).
Jean-Jacques Hublin emphasized:
“The Irhoud fossils demonstrate that modern facial morphology was already present 300,000
years ago. Brain size was within the modern range, but brain shape was still archaic.
”
(Hublin et al., 2017, p. 289)
This fact is startling. It means the hardware capacity of the brain was present
long before the symbolic record.
Brain Shape: The Globularity Puzzle
If size was not the key, perhaps shape was. Sarah Neubauer and colleagues
(2018) analyzed endocasts from fossils dated 300–35 ka. They discovered that
early Homo sapiens had elongated, archaic vaults. Only later did the fully
globular skull— with expanded parietal lobes and cerebellum — emerge.
Neubauer et al. concluded:
“Brain shape evolved within Homo sapiens after its origin. Globularization may reflect
changes in neural connectivity important for language and social cognition.
” (Neubauer,
Hublin & Gunz, 2018, p. 2)
Thus, even though the hardware volume was ready, the architectural design
— the internal wiring and distribution — matured later.