German, in contrast to English, has a relatively free word order. For instance, the first determiner phrase (DP, pronoun or article+ noun ) after the complementizer can be either the subject or the object of the complement clause as a result of case ambiguity (nominative vs. accusative). Sentences can be constructed which are ambiguous until the number information of the finite verb appears:
Results of reading experiments, which investigated the processing of subject-object ambiguities in German, showed that participants have severe problems to process sentences like (1b) . This well established garden-path effect is clearly smaller in sentences with a pronominal object like (2b). One reason for the processing difference in scrambled sentences with pronouns in contrast to referential DPs could be, apart from the necessary syntactic reanalysis in both sentence types, the additional revision of the prosodic/focus structure.
To investigate this hypothesis, we carried out two reading experiments using event-related brain potentials (ERP) to differentiate between processes of syntactic reanalysis on the one hand and the revision of the prosodic/focus structure on the other hand. The data analysis showed two different components in the first experiment (ERPs were measured time-locked to the presentation of the auxiliary): An early positivity (300-400 ms) which could be interpreted as reanalysis of the syntactic structure, and a right anterior negativity (400-600 ms) which might be seen as the correlate of focus structure revision.
To further test this hypothesis, we tried to eliminate the difference in the focus structure between the two sentence types through the insertion of a focus particle in front of the second DP, and furthermore, to prevent the parser from a focus structure revision . If the right anterior negativity in the first experiment is correctly correlated with the additional revision of the focus structure in the sentences with referential DPs, it should disappear in the second experiment. As predicted, there was no right anterior negativity, whereas the early positivity (300-400 ms) was still elicited. These results support the assumption that the process of reanalyzing a sentence is harder if the comprehension system has to re-structure the input on different representational levels, including prosodic/focus structure.
References
Bader, M. & Meng, M. (1999): Subject-Object Ambiguities in German Embedded Clauses: An Across-the-Board Comparison. Journal of Psycholinguistic Research, 28 (2), 121-143.
Friederici, A. D., Mecklinger, A., Spencer, K. M., Steinhauer, K. & Donchin, E. (2001): Syntactic Parsing Preferences and Their On-Line Revisions: A Spatio-Temporal Analysis of Event-Realted Brain Potentials. Cognitive Brain Research 11, 305-323.
Mecklinger, A., Schriefers, H., Steinhauer, K. & Friederici, A. D. (1995): Processing Relative Clauses Varying On Syntactic and Semantic Dimensions: An Analysis with Event-Related Potentials. Memory & Cognition 23 (4), 477-494.