It has been a long-standing puzzle that Negative Polarity Items appear to split into two subvarieties when their effect on the interpretation of questions is taken into account: while questions with any and ever can be used as unbiased requests of information, questions with so-called `minimizers', i.e. idioms like lift a finger and the faintest idea, are always biased towards a negative answer (cf. Ladusaw 1979). Focusing on yes/no questions, this paper presents a solution to this puzzle. Specifically it is (...) shown that in virtue of containing even (cf. Heim 1984), minimizers, unlike any, trigger a presupposition, which reduces the set of the possible answers to a question to the singleton containing the negative answer. (shrink)