Question tags and sentential negativity

• The paper argues that sentential negativity is a graded notion.
• The argument is based on a new experimental tool to diagnose negativity.
• This experimental tool involves the formation of tag questions.
• Both semantic and syntactic factors influence the negativity of a sentence.

This paper presents an experiment that is designed to quantify the negativity of sentences with different types of negative operators (n-words like never and downward entailing operators like rarely) in different syntactic positions (adverb, subject, and direct object). In the experiment, participants were provided with a minimal context, then asked to choose one tag-question out of two; one of questions had a positive tag and the other had a negative tag. Clearly positive sentences (i.e., sentences without any negative operators) and clearly negative sentences (i.e., sentences with overt sentential negation and no other relevant operators present) were used as controls. The relative frequency of positive and negative tags was then taken as a measure of the sentential negativity of each experimental item. Our main finding is that sentential negativity is a graded notion, sensitive to both semantic and syntactic factors. With respect to semantics, we find that n-words contribute more negativity than downward entailing operators, confirming the logical distinction between anti-additivity and downward entailment identified in the previous semantic literature on NPI licensing. With respect to syntactic position, we find that negative items in subject or adverbial position contribute more negativity than negative items in direct object position.