Syntactic alignment and participant role in dialogue.

We report three experiments that investigated whether the linguistic behavior of participants in a dialogue is affected by their role within that interaction. All experiments were concerned with the way in which speakers choose between syntactic forms with very similar meanings. Theories of dialogue assume that speakers address their contributions directly to their addressees, but also indirectly to side participants. In Experiments 1 and 2, speakers produced picture descriptions that had the same syntactic structure as a previous speaker's descriptions which had been addressed to a third person. This indicated that syntactic alignment is not limited to speaker-addressee dyads. However, the prior participant role of the current speaker affected alignment: prior addressees aligned more than prior side-participants. In contrast, Experiments 2 and 3 demonstrated that alignment was unaffected by the prior participant role of the current addressee. We interpret these findings in terms of depth of processing during encoding.