# Conflict-arrival curricula — does the decline (and the collapse) follow conflict, or generation?

**Claim tested (manuscript revision 2026-09-12).** In the Latin-square population the fraction of
merges a lineage declines rose with generation, and the obligate-merge arm collapsed from generation
4. Three things rise together there: adapter age, skill count, and the arrival of the two families
whose answer conventions conflict (`boolq` yes/no, `winogrande` 1/2). The decorrelated curriculum
separated complementarity from generation but not conflict arrival. These two curricula move ONLY
conflict arrival: **conflict-early** puts `boolq`/`winogrande` in generations 1–2 of every lineage;
**conflict-late** puts them in generations 5–6; the four compatible families fill the rest in
rotated orders. Age and skill count rise one family per generation in both (tested in
`tests/test_llm_curriculum.py`). Pre-registered readings: declines and collapse at generations 2–3
in early and 5–6 in late → conflict arrival drives them; the same rise/collapse schedule in both →
age or skill count.

**Setup.** As `curriculum_v5` (Qwen2.5-1.5B base, 3 lineages, 6 generations, 300 new + 150 replay
examples, rank-16 LoRA, 60 test items per family). Configs: `curriculum_v5_{early,late}.yaml`
(arms `isolated` + declinable `society`) and `curriculum_v5_{early,late}_obl.yaml` (obligate
`society`). Seeds 1–3 via `hpc/llm_curriculum_timing.pbs` (L40S, 20–40 min per element). Bundles:
`results/llm_curriculum_v5_{early,late,early_obl,late_obl}/s{seed}/`. Figure
`curriculum_timing.png` (this directory); numbers below from `figures/stats_llm_curriculum.py`.

### Result — generation, not conflict arrival
- **Declines rise with generation in both curricula on the same schedule** (mean fraction declined,
  generations 1→6; conflict present from generation 2 in early, 6 in late):
  early 0.56, 0.33, 0.67, 0.67, 0.89, 0.78 · late 0.44, 0.67, 0.44, 0.56, 0.78, 0.89
  (Latin 0.44 → 1.00; decorrelated 0.44 → 0.89).
- **Conflict-timing test** (partial Spearman of declined on a conflict-present indicator,
  controlling for generation; seed-clustered bootstrap): early + late pooled, n = 36:
  ρ(conflict | generation) = **−0.09**, 95% CI (−0.45, 0.15); ρ(generation | conflict) = **+0.45**.
  All four curricula pooled, n = 72: ρ(conflict | generation) = −0.04, CI (−0.30, 0.15);
  ρ(generation | conflict) = +0.39. Complementarity, pooled over four curricula with generation
  controlled: +0.05, CI (−0.08, 0.20).
- **Obligate collapse also follows generation.** Best-lineage all-families accuracy of the obligate
  arm, generations 1→6, mean of 3 seeds: early 0.63, 0.61, 0.72, 0.68, 0.50, 0.28 · late 0.75,
  0.76, 0.71, 0.61, 0.57, 0.44 (Latin 0.68 … 0.27). Conflict-early dips when the pair arrives
  (generation 2), recovers to the others' level by generation 3, and collapses from generation 5;
  conflict-late collapses from generation 4 with its conflicting pair still to come, and ends
  less deep. Final obligate − isolated: early −0.517 ± 0.050, late −0.395 ± 0.053 (3/3 seeds each).
- **Declinable arms finish level with never merging in both curricula:** early 0.777 vs 0.796
  (per seed −0.022, −0.039, +0.003), late 0.791 vs 0.781 (+0.019, +0.003, +0.006).

**Reading.** With conflict arrival moved by four generations, neither the decline curve nor the
collapse moved with it. What remains confounded is adapter age with skill count (both rise one per
generation by construction). The recombination-modifier reading (declines track complementarity)
stays unsupported; the "conflict arrival explains the collapse" reading is now also unsupported at
the level of timing, though conflicting conventions still set the per-pair error floor
(Proposition S2) and the early-arrival dip is visible. Falsifier for the generation reading (not
triggered): declines or collapse shifting by ≥ 3 generations between the two curricula.