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The Ādam Paradox Hypothesis 135
Social Nets: Scaling the Human Web
The survival of early humans depended not only on calories or tools but on
relationships. No foraging band could endure droughts, defend territories, or
raise children without trust. Yet trust, unlike stone or bone, leaves no fossil. It
must be inferred from the traces of social nets — the webs of relationships
binding individuals into groups.
The paradox is this: primates, including our closest relatives, are constrained in
group size by biology. How, then, did Homo sapiens shatter this ceiling and
construct societies of hundreds, thousands, and eventually millions?
The answer lies in symbols.
Grooming and the Limits of Biology
In the 1990s, anthropologist Robin Dunbar asked a deceptively simple
question: Why do primates groom? His answer transformed anthropology.
Grooming, he argued, is not just about hygiene but about social bonding.
When one chimpanzee picks lice from another’s fur, it is cementing an alliance,
building trust, and defusing conflict.
Dunbar then noticed a correlation: the size of primate groups scales with the
size of the neocortex. In chimpanzees, with relatively smaller brains, groups
average around 50 individuals. In baboons, with larger brains, groups stretch to
80 or more. Extrapolating to humans, Dunbar calculated that our neocortex
should support stable groups of about 150 individuals — a figure now called
Dunbar’s Number (Dunbar, 1996).
This number recurs strikingly in ethnography. Many traditional villages, military
units, and company divisions cluster around ~150 members. Beyond this
threshold, groups splinter or require formal structures. The implication is clear:
biologically, humans should have been capped at ~150 relationships.
But history tells another story. Humans did not stop at 150. We built tribes of
thousands, cities of tens of thousands, nations of millions. How?