Large Language Models (LLMs), despite their impressive capabilities, often fail to accurately repeat a single word when prompted to, and instead output unrelated text. This unexplained failure mode represents a vulnerability, allowing even end-users to diverge models away from their intended behavior. We aim to explain the causes for this phenomenon and link it to the concept of ``attention sinks'', an emergent LLM behavior crucial for fluency, in which the initial token receives disproportionately high attention scores. Our investigation identifies the neural circuit responsible for attention sinks and shows how long repetitions disrupt this circuit. We extend this finding to other non-repeating sequences that exhibit similar circuit disruptions. To address this, we propose a targeted patch that effectively resolves the issue without negatively impacting the model's overall performance. This study provides a mechanistic explanation for an LLM vulnerability, demonstrating how interpretability can diagnose and address issues, and offering insights that pave the way for more secure and reliable models.

本研究解决了大型语言模型（LLMs）在重复单词时常常输出无关文本的问题，揭示了这一现象的原因与“注意力沉没”概念之间的联系。研究发现了负责注意力沉没的神经电路，并提出了一种有效的解决方案，显著提高模型在长重复序列中的准确性，从而为大型语言模型的安全性和可靠性提供了新见解。

大型语言模型中重复标记现象的解释