Time-Driven Effects on Processing Relative Clauses

The present response time study investigated how a hypothesized time-based working memory constraint of 2-3 s affects the resolution of grammatical and semantic dependencies. Congruent and incongruent object relative (OR) and subject relative sentences were read at different presentation rates so that the distance between dependent words was either shorter or longer than 2-3 s. Incongruent OR sentences showed an effect of presentation rate. Experiment 1 focused on grammatical dependencies. Processing of adjectives with agreement features mismatching those of the preceding dependent word showed rapid agreement resolution at a time-interval below 2 s. Dependency intervals over 3 s reflected a different, more time-consuming process possibly due to extended search in sentence semantic representations as the grammatical form of the first word in the dependency fades away. In experiment 2, focusing on semantic dependencies, incongruent OR sentences displayed a different pattern: a gradual increase in processing time as a function of distance between dependent words. Thus, the 2-3 s long time-window seems to constrain the maintenance of grammatical forms in working memory.