arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2602.20332cs.CLcs.AIcs.LG

并非万能一种:用于缓解幻觉的QueryBandits

No One Size Fits All: QueryBandits for Hallucination Mitigation

JPMorgan AI Research(摩根大通人工智能研究院)

Nicole Cho, William Watson, Alec Koppel, Sumitra Ganesh, Manuela Veloso

AI总结:

QueryBandits通过在线学习优化查询重写策略,有效缓解闭源模型中的幻觉问题,优于传统静态策略。

摘要:

大型语言模型(LLMs)的高级推理能力导致幻觉现象更加频繁;然而,大多数缓解工作集中在开源模型的后验检测和参数编辑上。尤其值得关注的是,针对闭源模型中幻觉现象的研究尤其匮乏,因为它们构成了机构部署中大多数模型。我们引入了QueryBandits,一种模型无关的上下文老虎机框架,能够通过利用经过验证和校准的奖励函数,自适应地在线学习以选择最佳的查询重写策略。在16个问答场景中,我们的顶级QueryBandit(汤普森采样)在无重写基准上实现了87.5%的胜率,并分别比零样本静态策略(如改写或扩展)高出42.6%和60.3%。此外,所有上下文老虎机在所有数据集上均优于普通老虎机,特征方差越高,臂选择的方差也越高。这证实了我们的发现:没有一种重写策略对所有查询都最优。我们还发现,某些静态策略的累积遗憾高于无重写策略,表明不灵活的查询重写策略可能会加剧幻觉。因此,通过QueryBandits在语义特征上学习在线策略,可以纯通过前向传递机制改变模型行为,使其适用于闭源模型,从而避免重新训练或梯度适应的需要。

英文摘要:

Advanced reasoning capabilities in Large Language Models (LLMs) have led to more frequent hallucinations; yet most mitigation work focuses on open-source models for post-hoc detection and parameter editing. The dearth of studies focusing on hallucinations in closed-source models is especially concerning, as they constitute the vast majority of models in institutional deployments. We introduce QueryBandits, a model-agnostic contextual bandit framework that adaptively learns online to select the optimal query-rewrite strategy by leveraging an empirically validated and calibrated reward function. Across 16 QA scenarios, our top QueryBandit (Thompson Sampling) achieves an 87.5% win rate over a No-Rewrite baseline and outperforms zero-shot static policies (e.g., Paraphrase or Expand) by 42.6% and 60.3%, respectively. Moreover, all contextual bandits outperform vanilla bandits across all datasets, with higher feature variance coinciding with greater variance in arm selection. This substantiates our finding that there is no single rewrite policy optimal for all queries. We also discover that certain static policies incur higher cumulative regret than No-Rewrite, indicating that an inflexible query-rewriting policy can worsen hallucinations. Thus, learning an online policy over semantic features with QueryBandits can shift model behavior purely through forward-pass mechanisms, enabling its use with closed-source models and bypassing the need for retraining or gradient-based adaptation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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