EXPRESS: Typing speed and fluency as cues to uncertainty in the real-time production of written messages.

In spoken communicative contexts, speakers often convey uncertainty via intonation and through paralinguistic behaviors like speech rate and gesture-and addressees can use these behaviors to generate inferences about the speaker's epistemic state. In text-based contexts, however, cues of this sort are more restricted. In the present study, we examine the expression and reception of epistemic information in the context of real-time written message production. We hypothesized that real-time typing dynamics (like those available in text-based collaborative contexts such as Google Docs) can function as a rich paralinguistic cue about a partner's epistemic state. In Experiment 1, we collected production data showing that manipulations of typist certainty, instantiated through both the ease of message formulation and repeated experience with the task, are reflected in measures of typing fluency and speed. Then, in Experiment 2 we presented select screen recordings of the typing behaviors from Experiment 1 to a group of independent observers who made epistemic judgments about the typist. Our results show that observable differences in typing speed and fluency contribute to perceptions of typist knowledge and confidence, which has implications for interfaces that enable real-time text-based collaboration.