Individual differences in sense of agency and perspective adoption in comprehending Japanese null-subject sentences

When comprehending (Japanese) null-subject sentences, people mentally simulate the linguistically depicted events without adopting a particular point-of-view (i.e., perspective) (Sato &Bergen, 2013). The present study examined whether a sense of agency (SoA), measured by the Sense of Agency Scale (Asai et al., 2009), predicts individual preferences in perspective adoption associated with the null-subject sentence comprehension. In the experiment with the sentence-picture verification task, participants read null-subject sentences and decided whether the depicted action had been mentioned in the preceding sentence. The results showed that participants with relatively stable SoA verified the action pictures (e.g., cutting an apple) significantly faster when the event was depicted from an observer's perspective than when depicted from an agent's perspective. On the other hand, participants with relatively unstable SoA showed no preference for the pictured perspectives. We concluded that the unstableness of SoA may result in ambiguous attribution of an action, reflected as the absence of a preferred perspective when comprehenders simulate the described event. The reason why individuals with stable SoA prefer an observer's perspective was also discussed.