RING: Retrieval-Internalized Generation for Continual Large-Scale Knowledge Injection

2026-08-03Computation and Language

Computation and LanguageArtificial Intelligence
AI summary

The authors introduce RING, a new approach that puts external knowledge directly inside a language model instead of using slow, extra search steps during answering. They train the model in three parts: adding new knowledge, teaching it to search then answer, and using rewards to improve internal searching. Unlike older methods that rely on fixed searches, RING learns how to find information inside its own memory by itself. They also created a new news dataset to test if the model can handle truly new information. Their results show RING is as accurate and faster than previous methods that use external searches.

Retrieval-augmented generationMixture-of-Memory ExpertsDual Causal AttentionReinforcement LearningParametric MemoryLanguage ModelsKnowledge InjectionSearch PolicyNews-2025 Benchmark
Authors
Shicheng Xu, Liang Pang, Liyi Chen, Zihao Wei, Jingcheng Deng, Yan Gao, Yi Wu, Yao Hu, Huawei Shen, Xueqi Cheng
Abstract
Retrieval-augmented generation (RAG) improves factuality but adds latency and engineering overhead at serving time. We propose RING (Retrieval-Internalized Generation), a holistic paradigm spanning both architecture and training that injects large-scale external knowledge into a \textit{Mixture-of-Memory Experts} and learns parametric search over this internal memory via reinforcement learning, removing the external retriever entirely. Training proceeds in three stages: continued pre-training injects new corpora into a Knowledge Expert via our novel \textit{Dual Causal Attention}; supervised fine-tuning teaches a ``search-then-answer'' pattern; and reinforcement learning with hierarchical rewards optimizes the routing-and-search policy over the parametric memory. Unlike prior parametric injection methods that pair internal memory with a fixed or rule-based retriever, RING {learns} its retrieval policy directly from task signals. We further frame RING theoretically as a search-free approximation to the classical RAG objective. To evaluate large-scale injection of genuinely {new} knowledge without test-time leakage, we further construct News-2025, a benchmark built from news strictly post-dating the base LLM's pretraining cutoff. RING matches or surpasses both search-based RAG and parametric injection baselines in accuracy and efficiency.