Conversations over video conferences: an evaluation of the spoken aspects of video-mediated communication

Recent trends toward telecommuting, mobile work, and wider distribution of the work force, combined with reduced technology costs, have made video communications more attractive as a means of supporting informal remote interaction. In the past, however, video communications have never gained widespread acceptance. Here we identify possible reasons for this by examining how the spoken characteristics of video-mediated communication differ from face-to-face interaction, for a series of real meetings. We evaluate two wide-area systems. One uses readily available Integrated Services Digital Network (ISDN) lines but suffers the limitations of transmission lags, a half-duplex line, and poor quality video. The other uses optical transmission and video-switching technology with negligible delays, full duplex audio, and broadcast quality video.

To analyze the effects of video systems on conversation, we begin with a series of conversational characteristics that have been shown to be important in face-to-face interaction. We identify properties of the communication channel in face-to-face interaction that are necessary to support these characteristics, namely, that it has low transmission lags, it is two way, and it uses multiple modalities. We compare these channel properties with those of the two video-conferencing systems and predict how their different channel properties will affect spoken conversation. As expected, when compared with face-to-face interaction, communication using the ISDN system was found to have longer conversational turns; fewer interruptions, overlaps, and backchannels; and increased formality when switching speakers. Communication over the system with broadcast quality audio and video was more similar to face-to-face meetings, although it did not replicate face-to-face interaction. Contrary to our expectations, formal techniques were still used to achieve speaker switching. We suggest that these may be necessary because of the absence of certain speaker-switching cues. The results imply that the advent of high-speed multimedia networking will improve but not remove all the problems of video conferencing as an interpersonal communications tool, and we describe possible solutions to the outstanding problems.