Preferred modalities in dialogue systems

This research describes which modalities are preferred in particular contexts when interacting with a multi-modal dialogue system. The trade-off between three factors is investigated: (i) speech recognition performance, (ii) efficiency of input modality and (iii) the system 's output modality. Four versions were developed of a multimodal examinator to be used in elementary school. The versions differed in recognition performance (`perfect' vs. realistic) and output modality (speech or text). In all systems, subjects could provide input via speaking or typing. Answer length in characters was used as a measure of efficiency. Results show that both speech recognition performance and efficiency have a strong impact on preferred modalities. No effect was found of the system's output modality. 1. INTRODUCTION "Speech is the bicycle of user-interface design," according to Shneiderman (1998:328), "it is great fun to use (. . . ), but it can carry only a light load. Sober advocates know that ...