Empathetic and Emotionally Positive Conversation Systems with an Emotion-specific Query-Response Memory

Emotional conversation systems generate responses for the input queries considering the speaker's emotions in a conversation. Existing emotional conversation systems output emotional responses according to either a given emotion or the user's emotion reflected in the input queries. Following a given emotion may lead to an emotional drift between the given emotion and the conversation state, and following only the user's emotion may aggravate the user's negative feelings if users suffer from a negative mood. In this paper, we propose to generate empathetic responses catering to the user's emotions while leading the conversation to be emotionally positive. Particularly, by abstracting the conversation corpus, we extract and store the different responding strategies for different users' emotions and conversational topics into a memory. We encourage positive emotions in conversation via a sentiment evaluator. We model the memory outputs with a Gaussian mixture distribution and sample a final responding strategy from the distribution. The strategy acts as a condition to a transformer model to generate responses. The experiments verify our model surpasses the baseline methods in appropriateness, diversity, and generating emotionally positive responses.