Code and data associated with "The evolution of sex for artificial intelligence - A population-genetic framework for multigenerational model populations". Gilestro, 2026
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Giorgio Gilestro 39f6c9f4df hard benchmark: the 7B "fusion wins / no headroom" results were saturation artefacts
The easy task families saturated 7B (strings & arith at 1.00), so the earlier
7B nulls — moe: fusion 0.87 > union 0.84; directed ~= soup — could not separate
"refinements don't help at scale" from "tasks too easy at 7B". Adds a hard task
variant (hard: true in tasks.py: multi-step lists, Caesar ciphers / letter
transforms, multi-step & larger arithmetic; same family labels and answer
formats, threaded through make_tasks/train_specialist/runners; hard specialists
cache separately as spec_*_hard) and re-runs both experiments at 7B on Imperial
CX3 (one L40S, 24 min, unsaturated: arith ~0.48, strings 0.67, lists 0.34).

Both nulls flip back to the 0.5B ordering:
- Union beats fusion again: routing 0.500 > fusion 0.40 (soup 0.392 / ties
  0.400), the same 10-pt margin as 0.5B. Fusion dilutes the fragile strings
  specialist so hard (0.665 -> soup 0.300) that soup even trails the best single
  specialist (0.425); routing keeps it intact (0.670).
- Directed selection beats soup again: 0.492 > 0.392 (+10 pts), recovering most
  of routing's benefit from one deployable merged model (lifts strings to 0.630).

Correction to the earlier interpretation: the llm_moe_hpc "regime flip" and the
llm_directed_hpc "no headroom" null were driven by TASK SATURATION, not base
capability. The operative variable is headroom — "merge, don't average" (union >
fusion) and "directed sex" (selection > single blend) hold whenever there is room
to lose to dilution: a weak base (0.5B) OR hard tasks at a strong base (7B-hard).
Fusion only wins in the degenerate corner where easy tasks let a strong base
compose to the 1.00 ceiling. Vindicates E8's max > mean in real 7B weights once
saturation is controlled.

Default (easy) task behaviour is unchanged (hard defaults False). +1 hard-task
test (131 green). Excludes the 0.5B smoke bundle (a pipeline gate, not a
deliverable). Results in results/llm_{moe,directed}_hard_hpc/ (parquet gitignored).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-05 19:13:26 +01:00
configs hard benchmark: the 7B "fusion wins / no headroom" results were saturation artefacts 2026-07-05 19:13:26 +01:00
figures llm_directed: directed sex (breed offspring + select on verifier) — E10 in real weights 2026-07-05 18:35:04 +01:00
hpc hard benchmark: the 7B "fusion wins / no headroom" results were saturation artefacts 2026-07-05 19:13:26 +01:00
paper paper: reframe the perspective paper around sexual reproduction (v4 -> v5) 2026-07-05 13:53:10 +01:00
results hard benchmark: the 7B "fusion wins / no headroom" results were saturation artefacts 2026-07-05 19:13:26 +01:00
src hard benchmark: the 7B "fusion wins / no headroom" results were saturation artefacts 2026-07-05 19:13:26 +01:00
tasks hard benchmark: the 7B "fusion wins / no headroom" results were saturation artefacts 2026-07-05 19:13:26 +01:00
tests hard benchmark: the 7B "fusion wins / no headroom" results were saturation artefacts 2026-07-05 19:13:26 +01:00
.gitignore neural: real-MNIST external-validity tier (collapse + grounding) 2026-07-05 09:19:36 +01:00
CLAUDE.md hard benchmark: the 7B "fusion wins / no headroom" results were saturation artefacts 2026-07-05 19:13:26 +01:00
Makefile llm_directed: directed sex (breed offspring + select on verifier) — E10 in real weights 2026-07-05 18:35:04 +01:00
pyproject.toml llm: first real-LLM prototype — recombining specialist LLMs (C2/C4) 2026-07-05 15:48:02 +01:00
README.md paper: reframe the perspective paper around sexual reproduction (v4 -> v5) 2026-07-05 13:53:10 +01:00
uv.lock Layer 1.5: architecture-general neural existence proof 2026-07-04 21:02:49 +01:00

The Lamarckian Society — Layer 1 (analytical core)

A parametric population-genetics model of knowledge transmission across generations of learning agents. Knowledge transmission is modelled literally as a WrightFisher process (not by analogy): a model's knowledge is a distribution p_t over K discrete items; a fixed true distribution p* has a rare tail; each generational step is "sample from the parent (drift) + mix in fresh real samples (grounding/immigration) + refit." Model collapse is the loss of rare alleles under drift.

See paper/blueprint.md (the normative build spec), paper/the-lamarckian-society-v5.md (the perspective paper), and paper/results-summary.md (a summary of all results).

Reproduce

Environment is a uv venv built from the committed, hash-pinned uv.lock — that lockfile is the single source of truth for "it runs" (Layer 1 is pure NumPy/SciPy and bitwise-reproducible from a seed; no container needed).

# one-time: install uv (https://astral.sh/uv)
curl -LsSf https://astral.sh/uv/install.sh | sh

uv sync                 # build .venv from uv.lock
make test               # correctness + scientific-validation tests (the spine of trust)
make layer1             # run experiments E1E6
make figures            # regenerate figures from committed results

Layout

src/knowledge/   Layer 1 package (imported as `knowledge`)
configs/layer1/  one YAML per experiment (E1..E6)
figures/         plot_EX.py — read results.parquet only
tests/           test_correctness.py + test_scientific_validation.py (analytic checks)
paper/           blueprint.md, perspective paper, figure_manifest.md
results/         written artifacts (gitignored; hashes tracked in manifest.json)