In this paper, we investigate the interpretation of negated antonyms. A sentence such as Peter is not tall can be understood as meaning either that Peter is not tall tout court or that Peter is rather short (inference towards the antonym; ITA). We present the results of two experiments, in which we test two theoretical predictions. First, according to Krifka (2007), it is reasonable to expect a stronger ITA effect for positive versus negative adjectives. Second, elaborating on Krifka (2007), we expect ITA strength asymmetry to be greater for morphological antonymic pairs than for non-morphological pairs. In the first experiment, ITA strength was assessed implicitly by having participants judge the pragmatic acceptability of sentences involving a negated adjective and its antonym. In the second experiment, we collected explicit inferential judgments. The results of both experiments support the two predictions. We also discuss theoretical and methodological issues concerning the different notions of polarity.