Why only some adults reject under-informative utterances

Several studies have investigated how listeners generate scalar implicatures using the under-informative statement paradigm, where participants evaluate statements such as “Some of the cards have a star” as descriptions of situations in which all of the cards have a star. Rejection of the under-informative utterances is taken as evidence that participants have interpreted these sentences with a scalar implicature, to the effect that “Some but not all of the cards have a star”. However, acceptance rates of under-informative utterances exceed 35% in many studies (Bott and Noveck, 2004, Guasti et al., 2005, Pouscoulous et al., 2007; i.a.). The aim of our experimental investigation is to examine the cognitive or personality profile of participants who reject under-informative utterances. We provide empirical evidence that age and working memory capacity significantly predict the rate at which under-informative utterances are rejected, but find little support for influence from a broad range of personality factors.