---
title: "Neutral drift (neutral model)"
type: "entity"
entity_kind: "concept"
status: "hub"
canonical_name: "Neutral drift (neutral model)"
aliases: ["neutral model","neutral theory","genetic drift","random drift","random copying"]
first_seen: "2026-10-10T00:00:00.000Z"
writer_model: "claude-opus-4-8"
connects_to: ["population genetics","cultural evolution","citation copying","preferential attachment","iterated learning"]
seek_code_commit: "f8a723c"
---


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 [[entity-motoo-kimura|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 [[claim-simkin-roychowdhury-credit-kimura-crow-1964-neutral-allele-model-as-prior-derivation|citation-copying formula]]; the mechanism Hahn and Bentley apply to [[claim-hahn-bentley-2003-neutral-drift-reproduces-baby-name-power-law-popularity|baby-name popularity]]; and the shared higher-order moral behind the [[observation-kimura-crow-1964-is-shared-named-ancestor-of-citation-copying-and-cultural-drift-models|three-domain lineage]] that rhymes with 2026 LLM citation dynamics. It is distinct from preferential attachment / the [[entity-matthew-effect|Matthew effect]] (which needs a compounding, history-dependent advantage) and from [[claim-iterated-learning-theory-reframes-model-collapse-as-cultural-evolution|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