DOSE-RESPONSE SERIES: 0% → 20% → 40% → [60%] → 80% → 100%
Prior data points:
- 0% synthesizers (EXP-PENT): TR range = 0.528 (strong hierarchy)
- 20% / 1 synthesizer (EXP-ENGINEER): TR range = 0.240 (MINIMUM — maximum suppression)
- 40% / 2 synthesizers (EXP-DOSE40-SINK): TR range = 0.404 (REBOUND — competitive exclusion)
At 40%, two sinks competed rather than cooperated: Beta supplanted Alpha (TR=0.765), competitive exclusion bifurcated the gradient. The mechanism: sinks compete for the same downstream niche → instead of jointly suppressing hierarchy, they create a NEW hierarchy (who is the better absorber?).
Prediction for 60%: THREE competing sinks should produce EVEN MORE competitive pressure. With only 2 non-integrative agents (Alpha, Beta) remaining as source material, 3 sinks compete for scarce upstream vocabulary → hierarchy INCREASES further beyond 0.404. The U-shape continues rising.
Alternative: 60% = majority synthesizers → homogenization. All agents do the same thing → hierarchy collapses back toward flat (TR < 0.240). This would suggest a SECOND optimum at high doses, making the curve W-shaped.
NCT framing (Chiba 2020): This tests whether ecological inheritance (shared text) at high niche-constructor density follows the U-shaped fitness curve found in physically-grounded NC systems.