The MMN by another name? Exploring the autonomy of the Phonological Mapping (Mismatch) Negativity

The Phonological Mapping Negativity (PMN) is an event-related potential component thought to index pre-lexical phonological processing. The response has long been considered distinct from the temporally-proximate Mismatch Negativity (MMN) – a distinction that primarily rests on the assumption that the PMN, unlike the MMN, cannot be elicited in inattentive contexts, thus implying differing underlying auditory-cortex mechanisms. Despite this, no study to date has established whether elicitation of an inattentive PMN response is possible. Here, we tested this assumption in two experiments during which participants heard phonological mismatches whilst engaging in a distractor task (experiment 1) or watching a film (experiment 2). Our results showed no consistent evidence for an inattentive PMN. Though attention may indeed serve to distinguish the two components, our results highlight consistent discrepancies in the temporal, topographical, and functional characteristics of the PMN that undermine efforts to establish its significance in the electrophysiological timeline of speech processing.