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The Ādam Paradox Hypothesis 115
Scientific Debates
The archaeological synchrony of symbolism after ~70 ka has divided scholars
for decades. The central paradox is stark: why did anatomically modern humans, present
for hundreds of thousands of years, leave so little durable evidence of symbolic cognition until so
late?
Richard Klein, one of the most forceful voices, proposed a Human Revolution.
In his view, the leap to symbolic thought was triggered by a single genetic
mutation around 50,000 years ago.
“Anatomically modern humans existed long
before,
”Klein argued,
“but behaviorally modern humans emerged only ~50,000
years ago, perhaps triggered by a neural mutation that allowed the
unprecedented development of symbolic thought and language.
” (Klein, 2009, p.
270).
The elegance of the model lies in its simplicity, but critics faulted its lack of
mechanism. Which gene? How did it spread so rapidly? No evidence was
provided.
Ian Tattersall sympathized with the emphasis on rupture but dismissed the
“magic mutation” as unsatisfactory: “The appeal to a single genetic switch is too
simplistic. The evidence suggests a threshold event, yes, but not reducible to one gene.
”
(Tattersall, 2012, p. 211).
Paul Mellars offered another explanation: demography as driver. For Mellars,
symbols are fragile in small groups but stabilize in large, interconnected
populations. Around 70–60 ka in Africa, and 45 ka in Europe, densities rose
above a critical threshold, allowing traditions to persist.
“Symbolic behaviors are
fragile in small populations. Only when numbers rise, and groups interact across wide
networks, do symbols become stabilized and transmitted.
” (Mellars, 2006, p. 939).
The strength of this model is its grounding in cultural transmission theory,
which shows that languages and myths require redundancy to survive.
Yet Tattersall countered: “Demography may stabilize symbolism, but it cannot explain its
origin. Symbols do not emerge because of numbers; numbers grow because symbols expand
cooperation and identity.
”(Tattersall, 2012, p. 214).