@techreport{R-89-33, TITLE = {Empirical Studies of Discourse Representations for Natural Language Interfaces}, AUTHOR = {Nils Dahlb{\"a}ck and Arne J{\"o}nsson }, YEAR = {1989}, NUMBER = {R-89-33}, INSTITUTION = ida, ADDRESS = idaaddr, ABSTRACTURL = {/publications/cgi-bin/tr-fetch.pl?r-89-33+abstr}, ABSTRACT = {We present the results from a series of experiments aimed at uncovering the discourse structure of man-machine communication in natural language (Wizard of Oz experiments). The results suggest the existence of different classes of dialogue situations, requiring computational discourse representations of various complexity. Important factors seem to be the number of different permissible tasks in the system and to what extent the system takes initiative in the dialogue. We also analyse indexical expressions and especially the use of pronouns, and suggest a psychological explanation of their restricted occurrence in these types of dialogues.}, IDANR = {LiTH-IDA-R-89-33}, NOTE = {Also in Proc. of the 4th Conf. of the European Chapter of the Association for Computational Linguistics, Manchester, April, 1989}