SEMANTIC INFLUENCES ON PARSING - USE OF THEMATIC ROLE INFORMATION IN SYNTACTIC AMBIGUITY RESOLUTION

Ferreira and Clifton (1986, Experiment 1) found that readers experienc ed equal difficulty with temporarily ambiguous reduced relatives claus es when the first noun was animate (e.g., ''The defendant examined by the lawyer was . . .'') and when it was inanimate and thus an unlikely Agent (e.g., ''The evidence examined . . .''). This data pattern sugg ested that a verb's semantic constraints do not affect initial syntact ic ambiguity resolution. We repeated the experiment using: (1) inanima te noun/verb combinations that did not easily permit a main clause con tinuation, (2) a baseline condition with morphologically unambiguous v erbs (e.g., ''stolen''), (3) a homogeneous set of disambiguating prepo sitional phrases, and (4) a display in which all of the critical regio ns were presented on the same line of text. In two eye-movement experi ments, animacy had immediate effects on ambiguity resolution: only ani mate nouns showed clear signs of difficulty. Post-hoc regression analy ses revealed that what little processing difficulty readers had with t he inanimate nouns varied with the semantic fit of individual noun/ver b combinations: items with strong semantic fit showed no processing di fficulty compared to unambiguous controls, whereas items with weak sem antic fit showed a pattern of processing difficulty which was similar to Ferreira and Clifton (1986). The results are interpreted within the framework of an evidential (constraint-based) approach to ambiguity r esolution. Analyses of reading times also suggested that the milliseco nd per character correction for region length is problematic, especial ly for small scoring regions. An alternative transformation is suggest ed. (C) 1994 Academic Press, Inc.