Deep Reinforcement Learning for Dialogue Generation

Deep Reinforcement Learning for Dialogue Generation

November 1-5, 2016 | Jiwei Li¹, Will Monroe¹, Alan Ritter², Michel Galley³, Jianfeng Gao³ and Dan Jurafsky¹
This paper presents a deep reinforcement learning (RL) approach for dialogue generation, aiming to improve the long-term success of conversational agents. Traditional neural models for dialogue generation, such as sequence-to-sequence (SEQ2SEQ) models, often fail to generate engaging and diverse responses because they focus on maximizing the probability of the next utterance without considering the long-term impact of their choices. To address this, the authors propose integrating RL into dialogue generation to model future rewards and encourage more interactive and sustained conversations. The proposed model simulates dialogues between two virtual agents, using policy gradient methods to optimize for three key conversational properties: informativity, coherence, and ease of answering. The model uses an encoder-decoder architecture and defines simple heuristic approximations of rewards that characterize good conversations. These rewards are based on factors such as the ease of answering, semantic information flow, and semantic coherence. The model is trained using policy gradient methods, which allow it to optimize for long-term rewards rather than just the immediate likelihood of the next utterance. The model is evaluated on three metrics: dialogue length, diversity, and human judgment. Results show that the proposed RL model generates more interactive responses and sustains conversations longer than standard SEQ2SEQ models. The model also outperforms a mutual information-based model in terms of diversity and quality of generated responses. The RL model is able to generate more diverse and interactive responses, as well as produce higher quality multi-turn dialogues compared to the mutual information model. The paper also discusses the challenges of using RL for dialogue generation, including the difficulty of defining appropriate reward functions and the computational cost of exploring a large action space. The authors propose a curriculum learning strategy to gradually increase the complexity of the dialogue simulations, allowing the model to learn more effectively. The results demonstrate that the proposed RL model is able to generate more engaging and sustained conversations, making it a promising approach for future dialogue systems.This paper presents a deep reinforcement learning (RL) approach for dialogue generation, aiming to improve the long-term success of conversational agents. Traditional neural models for dialogue generation, such as sequence-to-sequence (SEQ2SEQ) models, often fail to generate engaging and diverse responses because they focus on maximizing the probability of the next utterance without considering the long-term impact of their choices. To address this, the authors propose integrating RL into dialogue generation to model future rewards and encourage more interactive and sustained conversations. The proposed model simulates dialogues between two virtual agents, using policy gradient methods to optimize for three key conversational properties: informativity, coherence, and ease of answering. The model uses an encoder-decoder architecture and defines simple heuristic approximations of rewards that characterize good conversations. These rewards are based on factors such as the ease of answering, semantic information flow, and semantic coherence. The model is trained using policy gradient methods, which allow it to optimize for long-term rewards rather than just the immediate likelihood of the next utterance. The model is evaluated on three metrics: dialogue length, diversity, and human judgment. Results show that the proposed RL model generates more interactive responses and sustains conversations longer than standard SEQ2SEQ models. The model also outperforms a mutual information-based model in terms of diversity and quality of generated responses. The RL model is able to generate more diverse and interactive responses, as well as produce higher quality multi-turn dialogues compared to the mutual information model. The paper also discusses the challenges of using RL for dialogue generation, including the difficulty of defining appropriate reward functions and the computational cost of exploring a large action space. The authors propose a curriculum learning strategy to gradually increase the complexity of the dialogue simulations, allowing the model to learn more effectively. The results demonstrate that the proposed RL model is able to generate more engaging and sustained conversations, making it a promising approach for future dialogue systems.
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