The influence of speaker accent on the neurocognitive processing of politeness

Does speaking with a foreign accent alter how listeners respond to verbal requests? Cooperative outcomes depend on multiple social factors, such as the politeness of the speaker who makes a request (e.g., their tone of voice). However, little is known about how indexical features derived from the speaker's voice influence neurocognitive operations during politeness communication. In an event-related potential (ERP) study, 31 participants listened to requests ("Please lend me a nickel") that varied in prosodic politeness (polite/rude), imposition level (low/high cost to perform an action), and accent (native/foreign English speaker). In separate rating tasks, participants made a social inference (speaker friendliness) or pragmatic inference (likelihood of request compliance) about each request based on available speech cues. ERPs time-locked to request onset revealed an interaction of speaker accent and prosodic (im)politeness on the P200 component (180-260 ms) and the subsequent late positivity (450-700 ms). Findings pointed to rapid perceptual differentiation of the speaker's linguistic status and stance (P200), after which listeners attended more deeply to attitudinal cues expressed by native ingroup speakers. ERPs evoked by the sentence-final imposition word showed that speaker characteristics influenced how the "cost" of requests was later evaluated, hampering N400 semantic operations (300-500 ms) when speakers acted rudely or had a foreign accent-conditions less frequently associated with cooperative interactions. Selective uptake of particular social cues relevant for drawing social versus pragmatic inferences about requests was also noted. Our data identify a time course and brain mechanisms that integrate speaker and message during politeness communication.