Merged perception of PIN and PEN: Interspeaker variation or partial merger in perception?

Merged production of /ɪ/ and /ɛ/ before nasal consonants is well documented in Southern US English. In a previous study of merged perception of the /ɪ/-/ɛ/ contrast, we found that Southern listeners were partially merged in perception, in the sense that they were less sensitive to the contrast pre-nasally than pre-orally, but still not fully merged. However, the existence of individual partially merged Southern listeners was left unexplored. In the present study, we ask how many of the Southern individuals are partially merged in perception, as opposed to being fully merged or not merged. A 2AFC perception task asked US listeners from inside or outside the South to categorize stimuli on continua from bid to bed and bin to Ben. We fit a logistic regression model on probability of /ɛ/ responses as a function of continuum step, coda nasality, and individual. We found that most Southern listeners were partially merged, and the remainder were split between fully merged and not merged. In contrast, most non-Southern listeners were not merged. This finding supports the generalization that partial merger in perception is possible at the individual level, and indeed it is the most common outcome for the Southern individuals in this study.