  While recently developed NLP explainability methods let us open the black box
in various ways (Madsen et al., 2022), a missing ingredient in this endeavor is
an interactive tool offering a conversational interface. Such a dialogue system
can help users explore datasets and models with explanations in a
contextualized manner, e.g. via clarification or follow-up questions, and
through a natural language interface. We adapt the conversational explanation
framework TalkToModel (Slack et al., 2022) to the NLP domain, add new
NLP-specific operations such as free-text rationalization, and illustrate its
generalizability on three NLP tasks (dialogue act classification, question
answering, hate speech detection). To recognize user queries for explanations,
we evaluate fine-tuned and few-shot prompting models and implement a novel
Adapter-based approach. We then conduct two user studies on (1) the perceived
correctness and helpfulness of the dialogues, and (2) the simulatability, i.e.
how objectively helpful dialogical explanations are for humans in figuring out
the model's predicted label when it's not shown. We found rationalization and
feature attribution were helpful in explaining the model behavior. Moreover,
users could more reliably predict the model outcome based on an explanation
dialogue rather than one-off explanations.
