Learning high-quality dialogue representations is essential for solving a
variety of dialogue-oriented tasks, especially considering that dialogue
systems often suffer from data scarcity. In this paper, we introduce Dialogue
Sentence Embedding (DSE), a self-supervised contrastive learning method that
learns effective dialogue representations suitable for a wide range of dialogue
tasks. DSE learns from dialogues by taking consecutive utterances of the same
dialogue as positive pairs for contrastive learning. Despite its simplicity,
DSE achieves significantly better representation capability than other dialogue
representation and universal sentence representation models. We evaluate DSE on
five downstream dialogue tasks that examine dialogue representation at
different semantic granularities. Experiments in few-shot and zero-shot
settings show that DSE outperforms baselines by a large margin. For example, it
achieves 13% average performance improvement over the strongest unsupervised
baseline in 1-shot intent classification on 6 datasets. We also provide
analyses on the benefits and limitations of our model.Comment: NAACL 2022 main conferenc