Proceedings of the Annual Meeting of the Cognitive Science Society

Listeners quickly adapt to novel accents. There are three mainhypotheses for how they do so. Some suggest that listenersexpand their phonetic categories, allowing more variability inhow a sound is pronounced. Others argue that listeners shifttheir categories instead, only accepting deviations consistentwith the accent. A third hypothesis is that listeners both shiftand expand their categories. Most work has supported thecategory expansion hypotheses, with the key exception of Mayeet al. (2008) who argued for a shifting strategy. Here, we applythe ideal adaptor model from Kleinschmidt & Jaeger (2015)to reexamine what conclusions can be drawn from their data.We compare adaptation models in which categories are shifted,expanded, or both shifted and expanded. We show that modelsinvolving expansion can explain the data as well as, if not betterthan, the shift model, in contrast to what has been previouslyconcluded from these data.