Neural responses to interpersonal requests: Effects of imposition and vocally-expressed stance

Abstract

The way that speakers communicate their stance towards the listener is often vital for understanding the interpersonal relevance of speech acts, such as basic requests. To establish how interpersonal dimensions of an utterance affect neurocognitive processing, we compared event-related potentials elicited by requests that linguistically varied in how much they imposed on listeners (e.g., Lend me a nickel vs. hundred) and in the speaker's vocally-expressed stance towards the listener (polite or rude tone of voice). From utterance onset, effects of vocal stance were robustly differentiated by an early anterior positivity (P200) which increased for rude versus polite voices. At the utterance–final noun that marked the 'cost' of the request (nickel vs. hundred), there was an increased negativity between 300 and 500 ms in response to high-imposition requests accompanied by rude stance compared to the rest of the conditions. This N400 effect was followed by interactions of stance and imposition that continued to inform several effects in the late positivity time window (500–800 ms post-onset of the critical noun), some of which correlated significantly with prosody-related changes in the P200 response from utterance onset. Results point to rapid neural differentiation of voice-related information conveying stance (around 200 ms post-onset of speech) and exemplify the interplay of different sources of interpersonal meaning (stance, imposition) as listeners evaluate social implications of a request. Data show that representations of speaker meaning are actively shaped by vocal and verbal cues that encode interpersonal features of an utterance, promoting attempts to reanalyze and infer the pragmatic significance of speech acts in the 500–800 ms time window.