Predictability affects production: Thematic roles can affect reference form selection

- Tests conflicting claims about whether thematic roles affect reference form choices.
- Shows in multiple tasks that pronouns/zeros are used for goals more than sources.
- Demonstrates that goal reference is more predictable than source reference.
- Supports the conclusion that predictability affects reference form production.

Speakers use pronouns when referring to information that is topical, recently mentioned, or salient in the discourse. Although such information is often predictable, there is conflicting evidence about whether predictability affects reference form production. This debate centers on the question of whether reference form is influenced by the predictability of certain thematic roles. While some (Arnold, 2001) argue that referents in certain thematic roles are more likely to be pronominalized, others (Fukumura & van Gompel, 2010; Rohde & Kehler, 2014) argue that predictability does not play a role in determining referential form. We tested this puzzle in three experiments, using both a richly contextualized production paradigm, and two versions of the standard story-completion paradigm. In all experiments we manipulated the predictability of pairs of characters using transfer verbs. In all three experiments, we found that speakers used more pronouns when talking about the goal referent as opposed to the source. A rating experiment revealed that participants also expect goals to be mentioned more than sources. These results show that thematic role does affect both perceived predictability and the speaker's choice of reference form.