Listeners are better at predicting speakers similar to themselves

Although it takes several hundred milliseconds to prepare a spoken contribution, gaps between turns in conversation tend to be much shorter. To produce these short gaps, it appears that interlocutors predict the end of their partner's turn. The theory of prediction-by-simulation proposes that individuals use their own motor system to model a partner's upcoming actions by referring to prior production experience. In this study we investigate the role of motor experience for both predicting a turn-end and producing a spoken response by manipulating the similarity of heard speech to participants' own production style. We hypothesised that they would be better at predicting, and initiating responses to, speech produced in the style they speak themselves. Participants recorded a series of questions in two sessions, and several months later they listened to their own speech and that of a stylistically similar and a stylistically dissimilar participant (as assessed by independent raters). Participants predicted the end of 60 of these questions by pressing a button, and for the remaining 60 questions, by producing a spoken response. An analysis of response times showed that participants' button-press responses were faster for utterances spoken by themselves and by a stylistically similar partner, than for utterances spoken by a stylistically dissimilar partner. We conclude that simulation facilitates prediction of similar speakers.