Scalar diversity and negative strengthening

In recent years, experimental research has demontrated great variability in the ratesof scalar inferences across different triggering expressions (Doran et al. 2009, 2012, van Tielet al. 2016). These studies have been taken as evidence against the so-called uniformity assumption,which posits that scalar implicature is triggered by a single mechanism and that thebehaviour of one scale should generalize to the whole family of scales. In the following, wepresent an experimental study that tests negative strengthening for a variety of strong scalarterms, following up on van Tiel et al. (2016). For example, we tested whether the statementJohn is not brilliant is strengthened to mean that John is not intelligent (see especially Horn1989). We show that endorsement rates of the scalar implicature (e.g., John is intelligent butnot brilliant) are anti-correlated with endorsements of negative strengthening. Further, wedemonstrate that a modified version of the uniformity hypothesis taking into account negativestrengthening is consistent with van Tiel et al.’s data. Therefore, variation across scales may bemore systematic than suggested by the van Tiel et al. study.Keywords: Scalar diversity, scalar implicature, manner implicature, negative strengthening,inferencing task.