Plausibility leads to better comprehension but not syntactic adaptation: Evidence from structural disambiguation in...

In syntactic disambiguation, repeated exposure to less-preferred syntactic analyses may induce changes in parsing preferences, such that processing the less-preferred parses becomes easier while processing the preferred parses becomes difficult, known as "syntactic adaptation". However, previous studies have reported mixed findings, prompting the present study to reexamine this effect, using the ambiguous fragment V + N1 + DE + N2 in Mandarin Chinese, which is compatible with a relative clause (RC) structure (dominant parse) and a complement clause (CC) structure (secondary parse). To investigate whether the relative likelihood of syntactic parses affects syntactic adaptation, we conducted two self-paced reading experiments. Participants read sentences that started with ambiguous fragments with a stronger RC bias (Experiment 1) and a weaker RC bias (Experiment 2) and were later disambiguated as the CC analysis, with the bias manipulated through semantic plausibility. In both experiments, our results did not find adaptation on reading time for the dispreferred parse. We also did not find greater difficulty in parsing the preferred RC structure after exposure to the dispreferred CC structure. The offline comprehension accuracy, however, did show improvement. The comparison between the two experiments shows that increasing the likelihood of the dispreferred parse through semantic plausibility enhances the offline comprehension, but not the online reading time of this parse, highlighting a dissociation between what is syntactically preferred and what ultimately makes sense during sentence processing.