The quality of mediated-conversations under transmission delay

The influence of technical impairments on the perception of people using communication media has so far usually been considered from a single perspective. Most studies examine either the engineering side of communication systems or look at psychological aspects of users. The following work is incorporating these two views to gain a more complete picture of what happens if mediated communication is impaired. In particular, the focus lies on the influence of one specific degradation, pure transmission delay as experienced by the user. For this purpose, a framework is postulated representing a more complete view on the measurement of the quality in mediated conversations. The five components discussed that constitute the Quality of Mediated Conversations are: the Conversational Quality, the Mediated Interaction, the Experiencer, the Interaction Partners and the Circumstances. By means of laboratory experiments, the influence of the impairment pure transmission delay is investigated with relation to the proposed components. The focus here is on the components Conversational Quality, Mediated Interaction and the perception of the Interaction Partners. Seven experiments are conducted including twoand three-party groups. In six of these experiments, interlocutors are communicating over audio-only connections of three different speech bandwidths. The seventh experiment constitutes a first attempt to include audio-video Quality of Mediated Conversations into the framework as well. The results show that the Conversational Quality which can be considered as a measure of the perceived technical quality is related to the transmission delay present in the connection. This relationship is strongly dependent on the type of conversation and the intended interaction speed of the interlocutors. For this reason, a new parameter representing the delay sensitivity of a mediated conversation is introduced to enhance the prediction of the E-Model, an instrumental model predicting the Conversational Quality. The corresponding parameter is fitted based on the acquired data, and recommendations on values that could be used in a network-planning context are derived. Furthermore, a relationship of the delay sensitivity parameter and a measurement operationalising the component Mediated Interaction is shown. Beyond the considerations on Conversational Quality, the component Mediated Interaction is investigated further. Nonverbal interaction is examined and the newly developed metrics are found to be strongly effected by delay. The investigation of verbal interaction supports this outcome and confirms the assumption that communication under transmission delay is more difficult. More precisely, interlocutors experience severe changes during the course of conversation also when no change in the perceived Conversational Quality can be measured. Due to delay, utterances are not placed at the same point in time at each end, which leads to different communication “realities” at the different sites. As a result, the turn-taking system becomes unbalance and communication problems become far more prevalent. The third component which is considered in detail here, the Interaction Partners, plays another important role. Transmission delay is not directly perceivable as a