Language is widely assumed to be a well designed tool for re-liably communicating propositional information between peo-ple. This suggests that its users should be sensitive to failuresof communication, such as utterances that are blatantly inco-herent with respect to an ongoing conversation. We presentexperimental work suggesting that, in fact, people are surpris-ingly tolerant of conversational incoherence. In two previousstudies, participants engaged in instant-messaging conversa-tions that were either repeatedly crossed with other conversa-tions or had lines inserted into them that deliberately contra-dicted available information. In both cases, a substantial pro-portion of participants failed to notice. In a new study, confed-erates inserted unexpected, nonsensical lines into face-to-faceconversations. The majority of participants failed to notice.We argue these findings suggest that we should be wary ofmodeling spontaneous communication in terms of faithful in-formation transmission, or language as a well designed tool forthat purpose.

The ability to flexibly interpret signals in context is at the core of human communication, as even the most conventionalized linguistic signals are necessarily ambiguous and subject to inter-individual variability. We introduce a novel communication game (the Pizzini game) requiring pairs of participants to exchange linguistic signals that are successfully interpreted by using contextual information freshly generated by each pair. By allowing this common ground between once-strangers to be developed interactively in the lab, we are able to characterize the pair-specific contextual information available to participants when inferring intended meanings. We present preliminary data testing the predictions that (1) interactants align on an abstracted conceptual representation of a set of stimuli during the context-building portion of the task and (2) that the characteristics of this pair-specific conceptual representation predict the dynamics of how participants later resolve context-specific references to the same stimuli.

During communicative interactions, language production and comprehension are bounded by the accumulation of a shared communicative context. Besides lexical pacts and simplification of referential expressions, the creation of a shared context allows for the intelligible use of linguistic signals with novel, interaction-specific meanings. Here, we explore whether context-specific language use leads to mutual adjustment of interlocutors' conceptual representations. We tasked dyads with solving a referential communication game, quantifying dialogue-related adjustments in interlocutors' conceptual structures, and coordination dynamics during the interaction. After engaging in the dialogue, interlocutors judged the same set of referents more similarly than other participants engaged in the same task, but not with each other (pseudo-pairs). Exploratory analyses of the structural complexity of unfolding semantic spaces indicate a stronger alignment between interacting dyads than pseudo-pairs. These findings suggest that human communication is supported by structural coordination of conceptual representations of the communicative referents, over and above signal-level alignment.