Watch your tune! On the role of intonation for scalar diversity

Recent research has highlighted that lexical scales vary in their likelihood of giving rise to a scalar inference—a finding labeled scalar diversity. The current paper examines the role of intonation for this phenomenon, which has thus far primarily been studied using written materials. A specific focus in this regard was on the so-called rise-fall-rise contour, which has been argued to (i) convey uncertainty, which could have an influence on scalar inference calculation, and (ii) be sensitive to properties of lexical scales, which could interact with factors driving scalar diversity. Experiment 1 combined production with an inference task to assess the likelihood of different intonational contours, as well as how a given contour affects scalar inference rates. Production of the rise-fall-rise varied across lexical scales, as expected, and led to an increase in scalar inference derivation relative to a fall. The latter finding was further confirmed in Experiment 2, which explicitly manipulated intonational contours in the inference task. The results, thus, show the importance of taking intonation into account when studying scalar diversity and scalar inference more generally, and they also have implications for theories of the rise-fall-rise contour. Additionally, the experiments revealed a contour that is prosodically similar to the so-called Contradiction Contour, but appears to serve a different pragmatic function.