In English, double center-embedded sentences yield a so-called “missing VP illusion”: When they are ungrammatical due to a missing verb, they are judged as equally or even more acceptable than their grammatical counterparts. The illusion is often attributed to working memory limitations. Additionally, it has been suggested that statistical differences across languages—e.g., the lower frequency of consecutive verb clusters in verb-initial languages—play a role, since languages with verb-final embedded clauses are less susceptible to the illusion than English. In two speeded acceptability experiments, we demonstrate that the illusion arises in Spanish, a verb-initial language. We also find that the strength of the illusion is modulated by the number of consecutive verbs, consistent with the involvement of language statistics. By contrast, we do not find that participants’ working memory modulates the illusion, failing to support a role of memory limitations. Our results support the generalization that cross-linguistic variation in the missing VP illusion is associated with language statistics and verb position and they demonstrate that this is the case even in languages in which word order is not a reliable processing cue.

The comprehension of subject-verb agreement shows “attraction effects,” which reveal that number computations can be derailed by nouns that are grammatically unlicensed to control agreement with a verb. However, previous results are mixed regarding whether attraction affects the processing of grammatical and ungrammatical sentences alike. In a large-sample eye-tracking replication of Lago et al. ( 2015 ), we support this “grammaticality asymmetry” by showing that the reading profiles associated with attraction depend on sentence grammaticality. In ungrammatical sentences, attraction affected both fixation durations and regressive eye-movements at the critical disagreeing verb. Meanwhile, both grammatical and ungrammatical sentences showed effects of the attractor noun number prior to the verb, in the first- and second-pass reading of the subject phrase. This contrast suggests that attraction effects in comprehension have at least two different sources: the first reflects verb-triggered processes that operate mainly in ungrammatical sentences. The second source reflects difficulties in the encoding of the subject phrase, which disturb comprehension in both grammatical and ungrammatical sentences.