On the automaticity of reduction in dialogue: Cognitive load and repeated multimodal references

In conversation, speakers are likely to refer to the same objects more than once. These repeated references are reduced with respect to their initial counterparts, both in speech and gestures. In this paper we investigate the effect of cognitive load on the reduction of multimodal referring expressions. We report an experiment in which native speakers of Dutch engaged in a director-matcher task where repeated references were elicited, and a time constraint was imposed in order to increase the load. Our results show that articulatory, lexical, semantic, and gestural reduction took place irrespective of the cognitive demands. Nevertheless, we found that cognitive load moderated the extent to which these utterances were reduced, with reduction being less pronounced for speakers experiencing higher load. A subsequent perception experiment revealed that speakers with an increased load produced referring expressions that proved more informative to naïve listeners.