Multi-dimensional contributions to garden path strength: Dissociating phrase structure from case marking

Psycholinguistic investigations of reanalysis phenomena have typically focused on revisions of phrase structure. Here, we identify a further subcomponent of syntactic reanalysis, namely the revision of case marking. This aspect of reanalysis was isolated by examining German subject-object ambiguities that require a revision towards a dative-initial order. Since dative-initial orders are potentially unmarked, no phrase structure corrections are required, but the original, preference-based nominative assignment must be revised. Experiment 1, an ERP study, revealed an N400 component for reanalysis of case marking, which contrasted with a P600 component for phrase structure revisions. The 'reanalysis N400' was replicated in Experiment 2, which also showed that direct lexical support for a dative-initial order leads to a reduction of the effect. Finally, in Experiment 3, direct time course measures provided by the speed-accuracy trade-off (SAT) procedure supported the case reanalysis account by showing that conditions hypothesized to involve case reanalysis (dative-initial structures) require longer computation times than their nominative-initial counterparts. Lexeme-specific support for the dative-initial reading, however, does not lead to a faster computation of the target structure, but rather increases the likelihood that the correct interpretation will be computed. We interpret these findings as evidence for the general availability of an unmarked dative-nominative word order in German, the accessibility of which may be increased by lexical information. Moreover, the data show that syntactic reanalysis is not a homogeneous process, but may rather be subdivided along several dimensions that interact in determining overall garden path strength.