Grillo and Costa (2014) claim that Relative-Clause attachment ambiguity resolution is largely dependent on whether or not a Pseudo-Relative interpretation is available. Data from Italian, and other languages allowing Pseudo-Relatives, support this hypothesis. Pseudo-Relative availability, however, covaries with the semantics of the main predicate (e.g., perceptual vs. stative). Experiment 1 assesses whether this predicate distinction alone can account for prior attachment results by testing it with a language that disallows Pseudo-Relatives (i.e. English). Low Attachment was found independent of Predicate-Type. Predicate-Type did however have a minor modulatory role. Experiment 2 shows that English, traditionally classified as a Low Attachment language, can demonstrate High Attachment with sentences globally ambiguous between a Small-Clause and a reduced Relative-Clause interpretation. These results support a grammatical account of previous effects and provide novel evidence for the parser's preference of a Small-Clause over a Restrictive interpretation, crosslinguistically.

A sensible assumption in psycholinguistics is that universal principles of optimal computation guide structural decisions made during sentence processing. This idea was questioned by the apparent cross-linguistic variation in Relative Clause attachment: a wealth of experimental results from the nineties showed that speakers of Spanish, among other languages, more readily converged towards the least optimal structural resolution (i.e. non-local attachment) challenging the universality of parsing principles of locality. A more recent development in this literature demonstrated that previous results were confounded by the availability of an additional parse, the so-called Pseudo-Relative, in the ill-behaved languages (Grillo 2012; Grillo & Costa 2014). Grillo and colleagues further suggested that the parser more readily disambiguates in favour of the Pseudo-Relative reading, when possible, because of its structural and interpretive simplicity in comparison to Relative Clauses and that non-local attachment is a direct consequence of this independent preference. We present novel results in support of this account from two offline forced-choice attachment questionnaires in Spanish. The results show that Pseudo-Relative availability significantly affects attachment preferences and that cross-linguistic variation in Relative Clause attachment is likely to be epiphenomenal and largely attributable to underlying grammatical differences.