arXiv:2510.15731cs.CLcs.AI2025-10ACL被引 16

发现扩散语言模型的注意力会动态迁移且抗干扰能力强

Attention Sinks in Diffusion Language Models

  • 分析扩散模型注意力分布,发现其存在动态转移的注意力汇聚点
  • 移除注意力汇聚点仅导致性能轻微下降,表明模型鲁棒性强
  • 揭示扩散模型与自回归模型在注意力机制上的本质差异

掩码扩散语言模型(DLMs)作为传统自回归模型(ARMs)的有力替代方案,采用具备双向注意力的Transformer编码器,在实现并行生成的同时保持了竞争力。尽管其效率与效果已广泛研究,但其内部工作机制仍不明确。本文对DLM注意力模式进行实证分析,聚焦于注意力下沉现象——该现象此前已在多种Transformer架构中被观察到。结果表明,DLMs同样存在注意力下沉,但具有独特特征:首先,与自回归模型不同,其下沉位置在生成过程中呈现动态变化;其次,尽管自回归模型对注意力下沉极为敏感,但DLMs表现出强鲁棒性——遮蔽下沉位置仅导致性能轻微下降。这些发现为扩散语言模型的内在运作提供了新视角,揭示了其与自回归模型在注意力分配与利用方式上的根本差异。

原文摘要 · Abstract (English)

Masked Diffusion Language Models (DLMs) have recently emerged as a promising alternative to traditional Autoregressive Models (ARMs). DLMs employ transformer encoders with bidirectional attention, enabling parallel token generation while maintaining competitive performance. Although their efficiency and effectiveness have been extensively studied, the internal mechanisms that govern DLMs remain largely unexplored. In this work, we conduct an empirical analysis of DLM attention patterns, focusing on the attention sinking phenomenon, an effect previously observed in various transformer-based architectures. Our findings reveal that DLMs also exhibit attention sinks, but with distinct characteristics. First, unlike in ARMs, the sink positions in DLMs tend to shift throughout the generation process, displaying a dynamic behaviour. Second, while ARMs are highly sensitive to the removal of attention sinks, DLMs remain robust: masking sinks leads to only a minor degradation in performance. These results provide new insights into the inner workings of diffusion-based language models and highlight fundamental differences in how they allocate and utilize attention compared to autoregressive models.

扩散模型注意力机制语言建模

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