plain texts. Compared with text-level ECE, the
research of emotion cause extraction in conversa-
tion is at its preliminary stage. Poria et al. (2021)
propose this task for the first time, and apply neu-
ral approaches of text-level emotion cause extrac-
tion (Wei et al.,2020;Ding et al.,2020a,b).
Above traditional approaches treat conversa-
tional contexts as common plain text while us-
ing a Transformer-based encoder (Liu et al.,2019)
to learn the conversational context representation
for the ECEC task (Poria et al.,2021). These
approaches ignore the interaction information be-
tween utterances and conversational-specific fea-
tures. The problem could be serious when perform-
ing the ECEC task in long conversations.
The discourse structures in a conversation rep-
resent the interactive relationships between utter-
ances. Intuitively, these structures contain the po-
tential links between emotional utterances and their
corresponding cause expressions. As shown by the
solid arc on the left in Fig. 1, most of the emotion-
cause pairs are linked with the target utterance by
discourse relations. In addition, several findings
of previous studies on ECE support our point of
view. For instance, Hu et al. (2021b); Ding et al.
(2019) believe that the interaction features between
sentences could be useful information for the ECE
task.
In this paper, we propose a discourse-aware
model for ECEC. Concretely, we model ECEC and
discourse parsing in conversations (Afantenos et al.,
2015) jointly. It uses a shared pre-trained language
model (PLM) to represent conversational contexts.
The discourse parsing task can integrate rich ut-
terance interactions information into the shared
PLM. Besides, we use a gated graph neural net-
work (gated GNN) (Li et al.,2016) to explicitly
encode discourse structures that generated by the
discourse parser. In addition, we follow Wang et al.
(2021a), exploiting a gated GNN to further inte-
grate conversation-specific features such as the rel-
ative utterance distance and speakers to our model.
We conduct the experiments on the standard
benchmark dataset of the ECEC task to verify our
DAM model. Experiments show that the utterance
interaction features are effective for this task. When
the conversation-specific features are integrated by
gated GNN, the proposed model is able to obtain
further improvements.
To sum up, we make three main contributions as
follows:
•
We propose a discourse-aware model for
ECEC named DAM using multiple task learn-
ing and a gated GNN, which is able to inte-
grate rich utterance interaction features for
ECEC.
•
We further exploit a gated GNN to cap-
ture conversation-specific features such as the
relative utterance distance and speakers for
ECEC.
•
We advance the performance of the SOTA
models for ECEC.
We organize the rest of this paper as follows.
First, in Section 2, we introduce the related work.
Following in Section 3, we introduce the proposed
model, including the multi-task learning frame-
work, and the gated GNN module. Section 4and
Section 5describes our experiments on a bench-
mark dataset, verifying the effectiveness of our
proposed approach. Finally, we make conclusions
on Section 6.
2 Related Work
Prior research on emotion cause extraction can
be divided into two categories according to the
source text type: text-level emotion cause extrac-
tion (ECE) and emotion cause extraction in conver-
sation (ECEC) (Poria et al.,2021). For the ECE
task, early research adopts linguistic rules (Lee
et al.,2010;Chen et al.,2010;Russo et al.,2011)
and traditional machine learning (Gui et al.,2014,
2016,2018;Xu et al.,2017). In recently years,
several neural network models are introduced to
the ECE task with different granularities, such as
clause-level (Diao et al.,2020;Ding and Kejriwal,
2020;Hu et al.,2021a) and span-level (Li et al.,
2021c,a;Qian et al.,2021;Turcan et al.,2021;
Li et al.,2021b). Except for the text-level emo-
tion cause extraction, Poria et al. (2021) introduces
a new conversational dataset RECCON and the
Transformer-based baseline models.
Many researchers realize that there is a connec-
tion between ECE task and emotion recognition
task. In order to make full use of the interaction
between tasks, researchers use the multi-task frame-
work to carry out ECE task (Chen et al.,2018;Wu
et al.,2020). In addition, researchers take causal
reasoning as an auxiliary task (Fan et al.,2020;
Turcan et al.,2021) to enhance the reasoning abil-
ity of the model. However, most of these methods