Reference and the facilitation of search in spatial domains

Earlier work has suggested that, in hierarchically-ordered domains (e.g., a document divided into sections and subsections), referring expressions that are judiciously over-specied to a higher extent than is achieved by existing generation algorithms can make it considerably easier for a hearer to find the referent of the referring expression. The present paper investigates over-specication in spatial domains, which play an important role in daily life. We report an experiment whose aim is (1) to find out whether over-specification plays a similar role in spatial domains as in hierarchically ordered domains, (2) to obtain a better understanding of the reasons why over-specification can be helpful to hearers, and (3) to propose an algorithmic model of reference production that takes these findings into account. The results suggest that judicious over-specication
can facilitate search in a precisely defined class of problematic conditions (but less so in other cases) even if the hearer has previous knowledge about the domain. The implications of these findings are discussed and an algorithm for the generation of referring expressions is proposed that reflects them as closely as possible.