Delayed Aspectual Computation in Japanese: Evidence from Reduplicated Ideophones.

This study investigates the time course of aspectual computation in Japanese, employing a novel design utilizing ideophones as aspectual operators. We tested two competing hypotheses: one posits that aspectual computation occurs incrementally upon encountering aspect-related expressions, while the other suggests that computation is delayed until the entire predicate or clause is processed. Taking advantage of the strictly verb-final word order of Japanese, we manipulated aspect-related elements in preverbal positions to test these possibilities. Specifically, we contrasted simplex and reduplicated ideophones, which function as iterative operators, to manipulate single versus repeated event interpretations while keeping the verb constant. This design allows iterativity to be varied independently of verb semantics, avoiding confounds associated with verb-specific default interpretations. In two self-paced reading experiments, we examined the processing of aspectual mismatches between ideophones (simplex vs. reduplicated) and temporal adverbials (durative vs. non-durative), both placed before the verb, and found a significant interaction of the two factors such that participants read more slowly when simplex ideophones, which trigger single, semelfactive interpretations, were paired with durative adverbials. Crucially, this mismatch effect did not emerge in the preverbal, ideophone region, but instead appeared at the verb-spillover region in Experiment 1 and at the verb region in Experiment 2. These results provide the first experimental evidence that iconic morphological elements may contribute to aspectual interpretations and that aspectual information contributed by adverbial eventive operators is not fully computed until integration with the verb. We argue that this delayed computation arises because ideophones quantify over event variables introduced by the verb––thus, their aspectual impact is not fully computed until they are integrated with the verb.