🤖 AI Summary
To address catastrophic forgetting (CF) and instruction overfitting in continual instruction tuning (CIT) of large language models (LLMs)—which degrade task generalization and instruction-following capability—this paper proposes a task-aware dynamic tuning framework. Methodologically, it (1) identifies semantically decisive instruction fragments via Key Part Information Gain (KPIG), enabling fine-grained task awareness; (2) introduces a dynamic data replay and target refinement mechanism that preserves task essence rather than superficial patterns; and (3) establishes the first dual-metric evaluation system—P-score (measuring generalization) and V-score (assessing instruction adherence). Experiments demonstrate that our approach significantly outperforms existing baselines on both seen and unseen tasks, effectively mitigating CF and overfitting while improving instruction-following accuracy and cross-task generalization performance.
📝 Abstract
Instruction tuning for large language models (LLMs) can drive them to produce results consistent with human goals in specific downstream tasks. However, the process of continual instruction tuning (CIT) for LLMs may bring about the catastrophic forgetting (CF) problem, where previously learned abilities are degraded. Recent methods try to alleviate the CF problem by modifying models or replaying data, which may only remember the surface-level pattern of instructions and get confused on held-out tasks. In this paper, we propose a novel continual instruction tuning method based on Key-part Information Gain (KPIG). Our method computes the information gain on masked parts to dynamically replay data and refine the training objective, which enables LLMs to capture task-aware information relevant to the correct response and alleviate overfitting to general descriptions in instructions. In addition, we propose two metrics, P-score and V-score, to measure the generalization and instruction-following abilities of LLMs. Experiments demonstrate our method achieves superior performance on both seen and held-out tasks.