Document Type

Technical Report


Computer Science and Engineering

Publication Date






Technical Report Number



We report an experiment designed to compare human-human spoken dialogues with human-computer spoken dialogue. Our primary purpose was to collect data on the kinds of protocols that were used to control the interaction. Three groups of 12 subjects each were asked to complete tasks over the phone. These tasks involved the use of custom-calling features such as call-forwarding and speed-dialing. The experimental procedure was a new variation on the Wizard of Oz (WOZ) technique that allowed much clearer comparisons to be made between human-human and human-computer interactions. Subjects in the Operator Group were told they were talking to a human operator. Subjects in the second two groups were told they were talking to a machine when in fact their queries were dealt with by two humans. Of these two groups, one listened to a sample dialogue before attempting the tasks (Computer Group (T)), while the other did not (Computer Group (NT)). Previous studies have shown that there are significant differences between human-human and human-computer interactions. The aim of this study is to examine such differences more closely. While some effects can be attributed to the beliefs about computers the subjects bring to the task, others appear to be connected with the on-going interaction styles of the speakers. Our study focuses on effects created by differences in interaction style. An important feature of the study is the use of two wizard, a technique which results in a realistically degraded communication channel. This created an interaction style that was very distinct from that of the human operator.


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