Proceedings of the Annual Meeting of the Cognitive Science Society

Psycholinguistic studies have repeatedly demonstrated thatdownward entailing (DE) quantifiers are more difficult to pro-cess than upward entailing (UE) ones. We contribute to thecurrent debate on cognitive processes causing the monotonic-ity effect by testing predictions about the underlying processesderived from two competing theoretical proposals: two-stepand pragmatic processing models. We model reaction timesand accuracy from two verification experiments (a sentence-picture and a purely linguistic verification task), using the dif-fusion decision model (DDM). In both experiments, verifica-tion of UE quantifier more than half was compared to verifica-tion of DE quantifier fewer than half. Our analyses revealedthe same pattern of results across tasks: Both non-decisiontimes and drift rates, two of the free model parameters of theDDM, were affected by the monotonicity manipulation. Thus,our modeling results support both two-step (prediction: non-decision time is affected) and pragmatic processing models(prediction: drift rate is affected).