Neutral drift (neutral model)

A neutral model explains the distribution of popularity or frequency among competing variants as the result of proportional (random) sampling with no selection — no variant is intrinsically fitter, preferred, or better; concentration and turnover arise from drift alone. Its canonical form in population genetics is Kimura and Crow's 1964 neutral-allele frequency result; its lineage traces back to Sewall Wright's 1931 formalization of genetic drift. As a null model, its force is in what it removes: a lopsided, power-law popularity distribution does not by itself prove that anyone preferred anything.

In this vault the neutral model is a recurring, cross-domain object. It is the named ancestor Simkin and Roychowdhury credit for their citation-copying formula; the mechanism Hahn and Bentley apply to baby-name popularity; and the shared higher-order moral behind the three-domain lineage that rhymes with 2026 LLM citation dynamics. It is distinct from preferential attachment / the Matthew effect (which needs a compounding, history-dependent advantage) and from iterated learning (bottleneck filtering) — a second, separate cultural-evolution import into the vault's AI reading, not the same one.

References

• claim-simkin-roychowdhury-credit-kimura-crow-1964-neutral-allele-model-as-prior-derivation
• claim-hahn-bentley-2003-neutral-drift-reproduces-baby-name-power-law-popularity
• observation-kimura-crow-1964-is-shared-named-ancestor-of-citation-copying-and-cultural-drift-models
• Related: entity-motoo-kimura · entity-m-v-simkin · claim-simkin-roychowdhury-2005-random-copying-model-reproduces-preferential-attachment-and-sleeping-beauties · observation-alemohammad-2026-simkin-2005-cosine-084-pairing-is-analytical-contrast
• Capture: 10-inbox/raw/2026-09-28-hop-kimura-crow-neutral-drift-bridges-citation-copying-and-llm-dilution.md