Emotion-Cause Pair Extraction (ECPE) aims to identify the document's emotion clauses and corresponding cause clauses.Like other relation extraction tasks, ECPE is closely associated with the relationship between sentences.Recent methods based on Graph Convolutional Networks focus on how to model the multiplex relations between clauses by constructing different edges.However, the data of emotions, causes, and pairs are extremely unbalanced, but current methods get their representation using the same graph structure.In this paper, we propose a Joint Constrained Learning framework with Boundary-adjusting for Emotion-Cause Pair Extraction (JCB).Specifically, through constrained learning, we summarize the prior rules existing in the data and force the model to take them into consideration in optimization, which helps the model learn a better representation from unbalanced data.Furthermore, we adjust the decision boundary of classifiers according to the relations between subtasks, which have always been ignored.No longer working independently as in the previous framework, the classifiers corresponding to three subtasks cooperate under the relation constraints.Experimental results show that JCB obtains competitive results compared with state-of-theart methods and prove its robustness on unbalanced data.

Junhao Zheng, Qianli Ma, Shengjie Qiu, Yue Wu, Peitian Ma, Junlong Liu, Huawen Feng, Xichen Shang, Haibin Chen. Proceedings of the 61st Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers). 2023.

Emotion-cause pair extraction (ECPE) is an emerging task born out of Emotion cause extraction (ECE), which aims to extract the emotion clause and the corresponding cause clause simultaneously. Previous methods decompose ECPE into multiple sub-tasks, namely emotion clause extraction, cause clause extraction, and emotion-cause pair extraction, and employ different modules to address them separately. However, these methods fail to effectively capture the mutuality within the three sub-tasks, which may hinder the information interaction between emotion and cause. In this paper, we revisit and analyze the mutuality between emotion and cause clauses from a linguistic perspective and further propose a novel Modularized Mutuality Network (MMN) to capture the mutuality explicitly. Specifically, the mutuality can be divided into the following categories, including position bias, sentiment consistency, and natural duality. To this end, we design three modules wrapped with various simple but effective mechanisms to address the mutuality, respectively. Extensive experiments demonstrate that MMN achieves state-of-the-art performances on the ECPE task and detailed analyzed the effect of the three modules for capturing the mutuality within sub-tasks.

Emotion-cause pair extraction (ECPE) aims to extract emotion clauses and corresponding cause clauses, which have recently received growing attention.Previous methods sequentially encode features with a specified order.They first encode the emotion and cause features for clause extraction and then combine them for pair extraction.This lead to an imbalance in inter-task feature interaction where features extracted later have no direct contact with the former.To address this issue, we propose a novel Pair-Based Joint Encoding (PBJE) network, which generates pairs and clauses features simultaneously in a joint feature encoding manner to model the causal relationship in clauses.PBJE can balance the information flow among emotion clauses, cause clauses and pairs.From a multi-relational perspective, we construct a heterogeneous undirected graph and apply the Relational Graph Convolutional Network (RGCN) to capture the various relationship between clauses and the relationship between pairs and clauses.Experimental results show that PBJE achieves state-of-the-art performance on the Chinese benchmark corpus.