Continual learning in task-oriented dialogue systems can allow us to add new domains and functionalities through time without incurring the high cost of a whole system retraining. In this paper, we propose a continual learning benchmark for task-oriented dialogue systems with 37 domains to be learned continuously in four settings, such as intent recognition, state tracking, natural language generation, and end-to-end. Moreover, we implement and compare multiple existing continual learning baselines, and we propose a simple yet effective architectural method based on residual adapters. Our experiments demonstrate that the proposed architectural method and a simple replay-based strategy perform comparably well but they both achieve inferior performance to the multi-task learning baseline, in where all the data are shown at once, showing that continual learning in task-oriented dialogue systems is a challenging task. Furthermore, we reveal several trade-offs between different continual learning methods in term of parameter usage and memory size, which are important in the design of a task-oriented dialogue system. The proposed benchmark is released together with several baselines to promote more research in this direction.
@article{arxiv.2012.15504,
title = {Continual Learning in Task-Oriented Dialogue Systems},
author = {Andrea Madotto and Zhaojiang Lin and Zhenpeng Zhou and Seungwhan Moon and Paul Crook and Bing Liu and Zhou Yu and Eunjoon Cho and Zhiguang Wang},
journal= {arXiv preprint arXiv:2012.15504},
year = {2021}
}