Incremental processing of Tense Harmony and the disambiguation of clefted Relatives

We examine the processing of Tense Harmony, a semantic constraint requiring temporal compatibility between matrix and embedded clauses in English it-clefts (It was the gardener that was calling/*will call). Critically, Tense Harmony applies to Connected Clauses but not to string-identical clefted Relative Clauses. An acceptability judgment task shows that Tense Harmony violations receive significantly lower ratings and slower judgments compared to simple tense mismatches, despite being fully grammatical as a Relative Clause. A Grammatical Maze experiment reveals increased reading latencies immediately at the disambiguating region for these violations. Results demonstrate that Tense Harmony is computed incrementally, that clefted Relatives elicit garden-path effects, and that semantic constraints guide structural expectations. These findings support hybrid models of sentence processing incorporating not only retrieval but also predictive mechanisms in dependency formation, extending our understanding of how semantic and structural information interact in real-time sentence processing.