Pupil dilation reflects the authenticity of received nonverbal vocalizations

Abstract

The ability to infer the authenticity of other’s emotional expressions is a social cognitive process taking place in all human interactions. Although the neurocognitive correlates of authenticity recognition have been probed, its potential recruitment of the peripheral autonomic nervous system is not known. In this work, we asked participants to rate the authenticity of authentic and acted laughs and cries, while simultaneously recording their pupil size, taken as proxy of cognitive effort and arousal. We report, for the first time, that acted laughs elicited higher pupil dilation than authentic ones and, reversely, authentic cries elicited higher pupil dilation than acted ones. We tentatively suggest the lack of authenticity in others’ laughs elicits increased pupil dilation through demanding higher cognitive effort; and that, reversely, authenticity in cries increases pupil dilation, through eliciting higher emotional arousal. We also show authentic vocalizations and laughs (i.e. main effects of authenticity and emotion) to be perceived as more authentic, arousing and contagious than acted vocalizations and cries, respectively. In conclusion, we show new evidence that the recognition of emotional authenticity can be manifested at the level of the autonomic nervous system in humans. Notwithstanding, given its novelty, further independent research is warranted to ascertain its psychological meaning.

The neural basis of authenticity recognition in laughter and crying

“…Importantly, when we explored the simple effects of authenticity on ERP amplitudes for laughter and crying separately, we observed that the main effect on N100 was driven by the simple effect in crying, and the one on P200 by the simple effect in laughter (both effects being statistically significant). This evidence converges with the pupillometry evidence we have recently published from roughly the same sample of participants 64 , collected during the same experimental session. Therein, we observed a similar pattern of difference between laughter and crying.…”

“…Still, what drives salience attribution to non-authentic emotional vocalisations in the first place needs to be further narrowed down. We also suggest that what drives the early stages of authenticity recognition in crying and laughter might not be the same—with the former achieved through arousal, and the latter through a higher-order cognitive processing, en par with our pupillometry findings 64 . In sum, the current study—being the first to investigate authenticity recognition using EEG—hopefully serves as a driver of new hypotheses and independent studies—which will be helpful to substantiate the novel findings presented here.…”

“…Detailed results are presented in Supplementary Information (Supplementary Text A , Fig. S1 ) and published in the context of our pupillometry study conducted in the same experimental session and with an 85% sample overlap 64 .…”

“…Given the long duration of the task (36 min), three pauses of 30 s were distributed equally throughout the experiment for the participant to rest, to minimise fatigue. Pupillometry data were recorded alongside the EEG and are reported elsewhere 64 .…”

Is Pupil Activity Associated With the Strength of Memory Signal for Words in a Continuous Recognition Memory Paradigm?

“…Pupil amplitude artifacts (<1 or >9 mm), as well as drifts and blinks, were coded as missing values ( Rosa et al, 2015 ). Pupil diameters of zero lasting between 100 and 600 ms were considered blinks ( Cosme et al, 2021 ), and replaced using linear interpolation ( Carvalho and Rosa, 2020 ). Finally, a seven-point weighted average filter was applied to smooth data.…”