Negating compound sentences
Sangeet Khemlani, Isabel Orenes, Philip Nicholas Johnson-Laird · eScholarship (California Digital Library) · 2012
How do reasoners negate compound sentences, such as conjunctions of the form A and B and disjunctions of the form A or B or both?A theory based on mental models posits that reasoners negate each clause independently, and enumerate the various possibilities consistent with the negation.It makes a novel prediction: negations of conjunctions should be more difficult to comprehend than negations of disjunctions.Two experiments corroborate the prediction.Experiment 1 tested participants' ability to comprehend sentential negations by giving them assertions of the form: Bob denied that he wore a yellow shirt and he wore blue pants on Tuesday.Participants selected the clothing options that Bob possibly wore on Tuesday.Experiment 2 gave participants descriptions such as Bob loves Mary or Mary loves John or both, and they were required to formulate a denial by completing a sentence that started with "No, …".In both studies, participants' responses were more accurate for denials of disjunctions than denials of conjunctions.