When initial thematic role attribution lingers: Evidence for digging-in effects in Italian relative clauses

In Italian, relative clauses are syntactically ambiguous between a subject and an object reading when the subject and the object have the same number. In the absence of disambiguating cues, the parser analyzes the sentence as a subject relative clause, as subject relative clauses are easier to process than object relative clauses. However, the object reading can be triggered by morpho-syntactic and syntactic cues, such as agreement and word order. In two self-paced reading experiments, we investigate the effectiveness of these cues in triggering an object reanalysis by comparing cues that appear at an early processing stage (inside the relative clause) and cues that appear at a late processing stage (after the relative clause). Results show that reanalysis is attained more effortlessly for early cues, while late cues appears to trigger little or no reanalysis, suggesting that the longer the processor has been committed to the incorrect analysis, the harder is to undo the initial commitment (digging-in effect; Tabor & Hutchins 2004; see also Ferreira & Henderson 1991). From these results, we argue that one critical factor that affects ease of parsing is the processing stage at which a cue is made available in the input. We conclude with a discussion on the self-organized sentence processing model (SOSP), which provides a framework to capture these effects.