Attraction effects in Nungon reveal independent mechanisms for agreement and switch-reference marking

Like the majority of languages, Nungon, spoken by ~1,000 people in Papua New Guinea, has subject-verb agreement. However, it additionally requires speakers to mark verbs for whether the subject of the next, as-yet-unspoken sentence will be the same or different from the current sentence's subject. Here, we elicited narratives from Nungon speakers, manipulating properties of distractor nouns, to investigate this rare property known as switch-reference marking. We observed a strikingly high degree of agreement attraction errors (17%), but an even more striking number of "switch-reference attraction" errors: Zero. These findings reveal distinct processes for agreement and switch-reference marking, and resolve long-standing questions about agreement processing, favoring retrieval and feature-based accounts of agreement.