The effects of communication modes on performance and discourse organization with an adaptive interface

This paper reports a study of different communication patterns on performance with a simulated adaptive interface that created the impression of a talking and listening computer which would help participants solve problems with a computer. There were four levels of communication modes which differed in the restrictions placed on human-computer communication. Dependent measures included tasks completed per minute as well as participants' utterances, which were assessed for verbosity, disfluencies, and indices of common ground. The largest performance differences were found between the groups that could communicate freely and those where communication was restricted or denied. As restriction increased, performance decreased. Further, as restriction increased, the computer assumed greater control and verbosity decreased. Performance on the simple tasks declined as communication restriction increased, but no differences were observed for complex tasks. The results are discussed with respect to differences between human-human and human-computer communication as well as research on adaptive environments.