Where to Look and What to Use: Retrieve-Localize-Generate for Long-Term Conversational Memory Question Answering

2026-09-07

AI Summary

为解决长期对话记忆问答中证据分散及噪声问题，提出MemLoc框架，通过检索-定位-生成方法提高响应质量与准确性。

Abstract

Retrieval-augmented generation (RAG) enables large language models (LLMs) to answer questions by accessing external knowledge and has been widely adopted for long-term conversational memory question answering. However, existing methods suffer from two key challenges: (1) fragmented evidence scattered across temporally distant sessions, and (2) noisy content within retrieved sessions that triggers the lost-in-the-middle effect. To address these challenges, we propose MemLoc, a unified Retrieve-Localize-Generate framework for long-term conversational memory QA. For retrieval, MemLoc decomposes each session into multi-granularity memory units and performs query routing via an inner-memory graph with entropy-based granularity selection. It further models cross-session semantic and temporal dependencies through a cross-memory graph, enabling coarse-to-fine retrieval of top-K relevant memory candidates. For localization, we introduce a reasoning-based evidence locator trained with Self-reflective Hint Policy Optimization (SHPO), which performs progressive refinement by extracting query-relevant fragments within memory units to suppress noise and reranking across candidates to remove redundancy, producing a compact evidence set with lightweight location IDs. For generation, these IDs act as precise grounding signals that guide the LLM to the correct memory positions, mitigating the lost-in-the-middle effect while preserving original contextual integrity. Extensive experiments on four benchmarks demonstrate that MemLoc achieves state-of-the-art retrieval accuracy and response quality while maintaining efficiency. Our code is available at: https://github.com/Nikol-coder/MemLoc.

Problem

• long-term conversational memory
• retrieval-augmented generation
• fragmented evidence
• noisy content
• lost-in-the-middle effect

Innovation

• Retrieve-Localize-Generate
• entropy-based granularity selection
• cross-memory graph
• Self-reflective Hint Policy Optimization (SHPO)
• lightweight location IDs