A much-debated issue in current research on sentence parsing concerns the resolution of attachment ambiguities. Parsing theories differ on the procedures used to guide on-line attachment decisions: principle-grounded theories (e.g. garden-path/ construal) propose universal principles that minimize processing load; frequency-based accounts (such as linguistic tuning) claim that attachment decisions are shaped by readers' previous experience with their particular language; lexically based models, in turn, assert that attachment choices are determined by the properties of individual lexical items in the sentence. This paper reports six studies on late closure in the resolution of attachment ambiguities in Spanish: a questionnaire study on attachment preferences and three self-paced reading experiments where ambiguous PPs could be attached as arguments of two VP-hosts in NP-VP1-NPVP2-PP structures. The results show a clear preference towards low attachment (late closure), thus supporting principle-grounded theories. In addition, two corpus studies were carried out to obtain records of relative frequencies of the attachment choices involved in the experiments. A coarse-grained measure revealed that, in accordance with linguistic tuning, low-attachment structures are more common in Spanish NP-VP1-NP-VP2-PP sentences. However, a fine-grained count showed that low-attachment preferences cannot be explained by arguing that the specific verbs positioned lower on the tree (VP2) are more likely to take an extra argument than those located at a higher position (VP1), as lexical models would assume.