DEEPCOPY: Grounded Response Generation with Hierarchical Pointer Networks

Semih Yavuz, Abhinav Rastogi, Guan-Lin Chao, Dilek Hakkani-Tür
In SIGDIAL 2019 and NeurIPS 2018 Conversational AI Workshop (Best Paper)
[bib] [pdf]

title={{DEEPCOPY}: Grounded Response Generation with Hierarchical Pointer Networks},
author={Yavuz, Semih and Rastogi, Abhinav and Chao, Guan-Lin and Hakkani-T{\"u}r, Dilek},

Recent advances in neural sequence-to-sequence models have led to promising results for several language generation-based tasks, including dialogue response generation, summarization, and machine translation. However, these models are known to have several problems, especially in the context of chit-chat based dialogue systems: they tend to generate short and dull responses that are often too generic. Furthermore, these models do not ground conversational responses on knowledge and facts, resulting in turns that are not accurate, informative and engaging for the users. These indeed are the essential features that dialogue response generation models should be equipped with to serve in more realistic and useful conversational applications. Recently, several dialogue datasets accompanied with relevant external knowledge have been released to facilitate research into remedying such issues encountered by traditional models by resorting to this additional information. In this paper, we propose and experiment with a series of response generation models that aim to serve in the general scenario where in addition to the dialogue context, relevant unstructured external knowledge in the form of text is also assumed to be available for models to harness. Our approach extends pointer-generator networks by allowing the decoder to hierarchically attend and copy from external knowledge in addition to the dialogue context. We empirically show the effectiveness of the proposed model compared to several baselines including on CONVAI2 challenge.