From Fake to Real: Mitigating Out-of-Distribution Bias in In-Context Learning via Feedback Supervision from Large Language Models

摘要

With the rapid development of Large Language Models (LLMs), In-Context Learning (ICL) has emerged as one of the universal paradigms for unleashing the capabilities of LLMs. However, LLMs are generally plagued by various biases in context example selection, which can distort the model’s predictions. Although extensive research has focused on designing heuristic sample selection methods to mitigate biases in ICL, these approaches often struggle to adapt to highly biased out-of-distribution (OOD) scenarios with significant shifts between test samples and context samples. To overcome the aforementioned issue, this paper proposes a LLM-driven iterative derivation method for OOD data pseudo-labeling (named LPL), aiming to mitigate the risk of performance degradation caused by OOD bias by avoiding direct use of source data. To mitigate the misleading effects of noise in pseudo-labels, we propose a filtering metric that integrates model confidence and perturbation perplexity to enhance the quality of pseudo-labels. Subsequently, in each iteration, LPL utilizes this metric to expand new pseudo-labeled data as contextual demonstrations and ultimately adopts a voting mechanism to ensure the stability of the predictions. A series of experiments conducted on various LLMs have confirmed that our proposed method can effectively reduce OOD biases, thereby opening up new avenues for research in ICL biases.