Pairwise tagging framework for end-to-end emotion-cause pair extraction

摘要

Emotion-cause pair extraction (ECPE) aims to extract all the pairs of emotions and corresponding causes in a document. It generally contains three subtasks, emotions extraction, causes extraction, and causal relations detection between emotions and causes. Existing works adopt pipelined approaches or multi-task learning to address the ECPE task. However, the pipelined approaches easily suffer from error propagation in real-world scenarios. Typical multi-task learning cannot optimize all tasks globally and may lead to suboptimal extraction results. To address these issues, we propose a novel framework, Pairwise Tagging Framework (PTF), tackling the complete emotion-cause pair extraction in one unified tagging task. Unlike prior works, PTF innovatively transforms all subtasks of ECPE, i.e., emotions extraction, causes extraction, and causal relations detection between emotions and causes, into one unified clause-pair tagging task. Through this unified tagging task, we can optimize the ECPE task globally and extract more accurate emotion-cause pairs. To validate the feasibility and effectiveness of PTF, we design an end-to-end PTF-based neural network and conduct experiments on the ECPE benchmark dataset. The experimental results show that our method outperforms pipelined approaches significantly and typical multi-task learning approaches.