Neural evidence for perceiving a vowel merger after a social interaction within a native language

Although previous research has shown that speakers adapt on the words they use, it remains unclear whether speakers adapt their phonological representations, leading them to perceive new phonemic contrasts following a social interaction. This event-related potential (ERP) study investigates whether the neuronal responses to the perception of the /e/-/ε/ vowel merger in Northern French speakers show evidence for discriminating /e/ and /ε/ phonemes after interacting with a speaker who produced this contrast. Northern French participants engaged in an interactive map task and we measured their ERP responses elicited after the presentation of a last syllable which was either phonemically identical to or different from preceding syllables. There was no evidence for discrimination between /e/ and /ε/ phonemes before the social interaction, while mismatch negativity (MMN) and late responses revealed /e/-/ε/ discrimination after the social interaction. The findings suggest rapid neuronal adaptations of phonemic representations thanks to the social interaction.