Decay

Decay is the passive counterpart to active forgetting through suppression and pruning. Every memory has a decay rate that is applied multiplicatively on each consolidation cycle: a memory with retrieval priority 0.8 and a decay rate of 0.95 will have priority 0.76 after one cycle, then 0.72, then 0.68. Without retrieval and positive reinforcement to counteract it, priority trends toward zero. This is intentional: memories that are never retrieved are memories that have proven irrelevant, and irrelevant memories should fade. The multiplicative structure has an important interaction with Hebbian compounding - because compounding gains are added as a logarithmic bonus to retrieval priority, and because decay applies to the total priority including that bonus, compounding gains erode at the same rate as the base priority unless the memory is regularly retrieved and re-reinforced. High-reinforcement memories slow their own decay: the reinforcement scoring function adjusts the decay rate downward (high reinforcement leads to slow decay via the decayAdjustment field), creating a feedback loop where genuinely useful memories become more durable over time.