Does Chatbot Language Formality Affect Users’ Self-Disclosure?

Chatbots are increasingly used to replace human interviewers and survey forms for soliciting information from users. This paper presents two studies that investigate how the formality of a chatbot’s conversational style can affect the likelihood of users engaging with and disclosing sensitive information to a chatbot. In our first study, we show that the domain and sensitivity of the information being requested impact users’ preferred conversational style. Specifically, when users were asked to disclose sensitive health information, they perceived a formal style as more competent and appropriate. In our second study, we investigate the health domain further by analysing the quality of user utterances as users talk to a chatbot about their dental flossing. We found that users who do not floss every day gave higher quality responses when talking to a formal chatbot. These findings can help designers choose a chatbot’s language formality for their given use case.