Hey little sister, who's the only one? Modulating informativeness in the resolution of privative ambiguity

We present two eye-tracking experiments on the interpretation of sentences like "The tall girl is (not) the only one that ...," which are ambiguous between the anaphoric (the only girl that ...) and the exophoric interpretation (the only individual that ...). These interpretations differ in informativeness: in a positive context, the exophoric (strong) reading entails the anaphoric (weak), while in a negative context the entailment pattern is reversed and the anaphoric reading is the strongest one. We tested whether adults rely on considerations about informativeness in solving the ambiguity. The results show that participants interpreted one exophorically in both positive and negative contexts. Given these findings, we cast doubts on the idea that Informativeness plays a role in ambiguity resolution and proposes a Principle of Maximal Exploitation: When a context is provided, adults extend their domain of evaluation to include the whole scenario, independently from truth-conditional considerations about informativity and strength.