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Knowledge Unlearning for LLMs: Tasks, Methods, and Challenges

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arxiv 2311.15766 v2 pith:ICNQ5TQD submitted 2023-11-27 cs.CL

Knowledge Unlearning for LLMs: Tasks, Methods, and Challenges

classification cs.CL
keywords knowledgeunlearningllmsmethodschallengesexistingharmfullanguage
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved
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In recent years, large language models (LLMs) have spurred a new research paradigm in natural language processing. Despite their excellent capability in knowledge-based question answering and reasoning, their potential to retain faulty or even harmful knowledge poses risks of malicious application. The challenge of mitigating this issue and transforming these models into purer assistants is crucial for their widespread applicability. Unfortunately, Retraining LLMs repeatedly to eliminate undesirable knowledge is impractical due to their immense parameters. Knowledge unlearning, derived from analogous studies on machine unlearning, presents a promising avenue to address this concern and is notably advantageous in the context of LLMs. It allows for the removal of harmful knowledge in an efficient manner, without affecting unrelated knowledge in the model. To this end, we provide a survey of knowledge unlearning in the era of LLMs. Firstly, we formally define the knowledge unlearning problem and distinguish it from related works. Subsequently, we categorize existing knowledge unlearning methods into three classes: those based on parameter optimization, parameter merging, and in-context learning, and introduce details of these unlearning methods. We further present evaluation datasets used in existing methods, and finally conclude this survey by presenting the ongoing challenges and future directions.

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Cited by 10 Pith papers

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