LLMs exhibit "lost-in-the-middle" behavior due to their intrinsic attention bias, where they show a U-shaped attention pattern. This bias causes LLMs to focus more on tokens at the beginning and end of their input, regardless of relevance, resulting in weaker utilization of information in the middle of long contexts.
The "lost-in-the-middle" phenomenon affects LLM performance by causing a significant degradation in accuracy when crucial information is positioned amidst a lengthy context2. This behavior is attributed to the models' preference for information at the beginning or end of the input, leading to the neglect of vital data in the middle. As a result, LLMs struggle to robustly access and use information in long input contexts, impacting tasks that require processing and reasoning over extensive textual data.
Traditional methods to enhance LLMs in long-context settings typically involve fine-tuning on real-world datasets, which often include outdated or irrelevant information. This can lead to hallucinations and inaccuracies. Additionally, LLMs tend to exhibit a "lost-in-the-middle" behavior, where their performance is optimal at the beginning or end of the input context but deteriorates for information in the middle.