How to provide exactly one interpretation for every sentence, or what eye movements reveal about quantifier scope

A sentence with two quantifiers is potentially scope-ambiguous: the second quantifier may take narrow or wide scope with respect to the first one. Whether both interpretations are discernible, though, depends on factors like the type of the quantifier, its syntactic function, and word order. For instance, all tends not to take wide scope. When it appears in the object position, following a subject quantifier, the only perceived reading may be the one corresponding to the linear order of the quantifiers, as in (1a)