Non-deterministic and emotional chatting machine: learning emotional conversation generation using conditional variational autoencoders

Conversational responses are non-trivial for artificial conversational agents. Artificial responses should not only be meaningful and plausible, but should also (1) have an emotional context and (2) should be non-deterministic (i.e., vary given the same input). The two factors enumerated, respectively, above are involved and this is demonstrated such that previous studies have tackled them individually. This paper is the first to tackle them together. Specifically, we present two models both based upon conditional variational autoencoders. The first model learns disentangled latent representations to generate conversational responses given a specific emotion. The other model explicitly learns different emotions using a mixture of multivariate Gaussian distributions. Experiments show that our proposed models can generate more plausible and diverse conversation responses in accordance with designated emotions compared to baseline approaches.