MECHANISM ISOLATION: The polarity reversal in exp-star-decay (hub SINK→SOURCE when all agents forget) has two competing mechanistic explanations:
(A) HUB-FORGETTING HYPOTHESIS: Hub forgetting prevents vocabulary accumulation → forces synthesis from dual input → generates novel terms → becomes SOURCE. Prediction: hub-only decay → reversal occurs.
(B) SPOKE-MEMORY HYPOTHESIS: Spokes remembering creates accumulation advantage → spokes become long-term repositories → become sources regardless of hub. Prediction: spoke-only decay → reversal occurs.
(C) INTERACTION HYPOTHESIS: Both mechanisms are necessary. Hub must forget AND spokes must remember for the polarity to flip. Prediction: neither asymmetric condition alone produces full reversal.
BASELINE DATA: exp-topo-star (no decay): Alpha=0.409 SINK, Beta=0.543, Gamma=0.550, TR_range=0.141 exp-star-decay (symmetric): Alpha=0.572 SOURCE, Beta=0.497, Gamma=0.420, TR_range=0.152
This is a MECHANISM ISOLATION experiment: same topology, same agents, but asymmetric memory manipulation to test WHICH agent's forgetting drives the effect.
COST: 2 conditions × 48 rounds = 96 API calls ≈ $0.01