Who are you talking to? The role of addressee identity in utterance comprehension.

Experimental evidence suggests that speaker and addressee quickly adapt to each other from the earliest moments of sentence processing, and that interlocutor-related information is rapidly integrated with other sources of nonpragmatic information (e.g., semantic, morphosyntactic, etc.). These findings have been taken as support for one-step models of sentence comprehension. The results from the present event-related potential study challenge this theoretical framework providing a case where discourse level information is integrated only at a late stage of processing, when morphosyntactic analysis has been already initiated. We considered the case of Basque allocutive agreement, where information about addressee gender is encoded in verbal inflection. Two different types of Basque grammatical violations were presented together with the corresponding control conditions: one could be detected based on a morphosyntactic mismatch (person agreement violation), while the other could be detected only if the addressee's gender was considered (allocutive violation). Morphosyntactic violations elicited greater N400 effects followed by P600 effects, while allocutive violations elicited only P600 effects. These results provide new constraints to one-step accounts as they represent a case where speakers do not immediately adjust to the addressee's perspective. We propose that the relevance of discourse-level information might be a crucial variable to reconcile the dichotomy between one- and two-step models.