Italian sequence of tenses: complementation or imperfectivity?

In Italian Sequence of Tense (simultaneity of main and complement clause events) is expressed by an imperfective tense (Imperfetto), as in (1): Mario ha detto che Gianni mangiava una mela / M. said that G. ate-IMP an apple / 'Mario said that he was eating an apple'. Giorgi and Pianesi (1997) claim that temporal simultaneity in (1) is due to the anaphoric nature of the Imperfetto. Hollebrandse (1998) claims that at least in English and Dutch complementation is the crucial factor. It is the acquisition process that provides a difference between the two hypotheses: the 'Imperfective anaphoricity' and the Complementation hypothesis. To make this distinction we ran three experiments with 59 Italian children (3-6), who were tested on: (i) Aspect (probing knowledge of anaphoricity), (ii) Sequence of Tense and (iii) Theory of Mind (as a test for complementation). Not all 5-year-olds mastered the Imperfetto, while they show temporal simultaneity, therefore the anaphoric nature alone is not sufficient for the child to render simultaneous readings. We still conclude that both knowledge of the imperfective and knowledge of complementation play an important role in the acquisition of Sequence of Tense in Italian