The scalar interpretation of double negation

The meaning of expressions modified by double negation (e.g., not unhappy or not not interesting) has long been discussed, with views advocating that the two negations must be logically interpreted (i.e., not unhappy means happy), and others arguing that the modified expression always yields a weaker version than the unmodified expression. The current study aimed to understand the possible interpretations of double negation experimentally. We used a novel range-marking task, allowing (Hebrew-speaking) participants to mark not only the location of a certain expression on the scale, but also the size it occupies. We collected measures of the range sizes, their location, as well as the inclusion of the edge of the scale. Doubly-negated adjectives were compared to unmodified adjectives and singly-negated adjectives, and adjectives modified by hedges, considering their mitigation effect. We were able to provide the first empirical evidence that double negation can be interpreted both logically and pragmatically. Additionally, we showed dissimilarities between double negations and hedges, suggesting that doubly-negated expressions present a stronger mitigation effect than hedges.