Referential form and word duration in video-mediated and face-to-face dialogues

It is widely believed that speakers adapt their speech to meet the comprehension needs of their listener. Yet recent work in face-to-face communication has shown that word articulation and the design of referring expressions are insensitive to certain aspects of listener knowledge (Bard et al., 2000; Bard & Aylett, 2001). Word articulation and referential form were investigated in two studies. Study 1 examined the duration of words forming the names of landmarks on a map in video-mediated dialogues. Study 2 explored the impact of cognitive load (as illustrated by time pressure) on word duration and referential form in both face-to-face and video-mediated communicative contexts. It was found that second mentions of words were articulated more quickly than first mentions regardless of which interlocutor introduced the names of the landmarks (study one). Study two showed that speakers responded to time pressure by shortening the names of landmarks on a map but only when the task was video-mediated. Speakers did not, however, resist the pressure to shorten second mentions of words relative to first mentions under time pressure. The implications of these findings are discussed in terms of the Dual Process Model of speech processing in spoken dialogue proposed by Bard et al.,(2000).