Cortical processing of speaker politeness: Tracking the dynamic effects of voice tone and politeness markers

ABSTRACT

Information in the tone of voice alters social impressions and underlying brain activity as listeners evaluate the interpersonal relevance of utterances. Here, we presented requests that expressed politeness distinctions through the voice (polite/rude) and explicit linguistic markers (half of the requests began with Please). Thirty participants performed a social perception task (rating friendliness) while their electroencephalogram was recorded. Behaviorally, vocal politeness strategies had a much stronger influence on the perceived friendliness than the linguistic marker. Event-related potentials revealed rapid effects of (im)polite voices on cortical activity prior to ~300 ms; P200 amplitudes increased for polite versus rude voices, suggesting that the speaker’s polite stance was registered as more salient in our task. At later stages, politeness distinctions encoded by the speaker’s voice and their use of Please interacted, modulating activity in the N400 (300–500 ms) and late positivity (600–800 ms) time windows. Patterns of results suggest that initial attention deployment to politeness cues is rapidly influenced by the motivational significance of a speaker’s voice. At later stages, processes for integrating vocal and lexical information resulted in increased cognitive effort to reevaluate utterances with ambiguous/contradictory cues. The potential influence of social anxiety on the P200 effect is also discussed.

KEYWORDS:

• ERPs
• vocal expression
• speech processing
• social impressions
• social anxiety

Acknowledgments

The authors would like to thank Dr. Nikos Vergis for the design of the stimuli, and Alexandra Topilova and Emmanuelle Beauvais-Lacasse for their help in recruiting and testing participants.

Disclosure Statement

No potential conflict of interest was reported by the author(s).

Notes

¹ The filler stimuli were short compliments and criticisms, further details and analyses are available in (Mauchand et al., 2021).

⁵ Note that in this model, the N400 effects we reported may be interpreted as reflecting the ease of retrieval of syntactic, semantic and pragmatic information associated with the word. As the word Please was repeatedly presented in the experiment, it makes sense that retrieving its associated information was less effortful, explaining the pattern of results from another perspective. We include this interpretation for the sake of completeness, but endorse the interpretation offered above.

² For N1, we performed a peak detection procedure in the range of 100 to 210 ms using ERPLab, the peak occurred at 161.5 ms (sd = 29.5 ms); note that that repeating the same procedure separately for phrases with please and without please did not significantly alter the peak time (With please: M = 161.76 ms, sd = 30.54 ms; Without please: M = 161.22 ms, sd = 28.44 ms). For P2, we performed a peak detection procedure in the range of 200 to 300 ms), the peak occurred at 256.19 ms (sd = 25.07 ms); note that that repeating the same procedure separately for phrases with please and without please did not significantly alter the peak time (With please: M = 256.03 ms, sd = 25.77 ms; Without please: M = 256.34 ms, sd = 24.36 ms).

³ To validate our results in a hypothesis-independent manner, we performed a temporospatial principal components analysis (PCA) to identify underlying components sensitive to the experimental manipulations (Dien, 2012). Results largely aligned with the main analysis described above, revealing temporospatial factors in comparable time windows sensitive to the experimental manipulations (see Supplemental Materials for details).

⁴ Significant intercorrelations were observed between all anxiety-related measures: LSAS-SR was positively correlated with the STAI (State: r = .85, p < .001; Trait: r = .87, p < .001) and (r = .68, p < .001). The BFNE-II correlated with both STAI subscales (State: r = .55, p < .01; Trait: r = .61, p < .001).

Additional information

Funding

This work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) under grant # RGPIN-2016-04373 (“Neurocognitive studies of vocal emotions in speech”) to M.D Pell.