The effect of prolonged use on multimodal interaction

In this paper the effect of prolonged use on interaction with a multimodal sys­ tem is studied. The system accepts spoken input as well as pointing input and provides output both in speech and in graphics. We measured the usability of the system in a pre-test / post-test design and made a detailed analysis of the changes in interaction styles. The results of the study show that with practise users learn to develop interaction styles that ensure reliable and efficient input. This results in decreased dialogue duration and more user satisfaction.