Vocomotor and Social Brain Networks Work Together to Express Social Traits in Voices

Abstract

Voice modulation is important when navigating social interactions—tone of voice in a business negotiation is very different from that used to comfort an upset child. While voluntary vocal behavior relies on a cortical vocomotor network, social voice modulation may require additional social cognitive processing. Using functional magnetic resonance imaging, we investigated the neural basis for social vocal control and whether it involves an interplay of vocal control and social processing networks. Twenty-four healthy adult participants modulated their voice to express social traits along the dimensions of the social trait space (affiliation and competence) or to express body size (control for vocal flexibility). Naïve listener ratings showed that vocal modulations were effective in evoking social trait ratings along the two primary dimensions of the social trait space. Whereas basic vocal modulation engaged the vocomotor network, social voice modulation specifically engaged social processing regions including the medial prefrontal cortex, superior temporal sulcus, and precuneus. Moreover, these regions showed task-relevant modulations in functional connectivity to the left inferior frontal gyrus, a core vocomotor control network area. These findings highlight the impact of the integration of vocal motor control and social information processing for socially meaningful voice modulation.

The neural control of volitional vocal production—from speech to identity, from social meaning to song

“…Another difference that may be important in these studies is that some instruct the participants to actively change their voices (e.g. the vocal changes used in [50,55]), while others give the participants tasks that will implicitly lead to vocal change, even if the participants are not directly aware of this (e.g. the auditory manipulations of speech production discussed by Meekings & Scott [53], the joint speech task used by Jasmin et al [56]).…”

“…Mcgettigan and colleagues (Guldner et al, 2020) asked participants to overtly express two different dimensions of social information -participants were asked to read non-words aloud and to express social traits of competence (e.g. intelligent) and affiliation (e.g.…”

“…By contrast, the expression of social traits (over the nonsocial trait of size) resulted in activations in memory-related circuits such as the left hippocampus and bilateral retrosplenial, visual imagery-related fields such as the left cuneus and precuneus and the bilateral lingual gyri, and semantic fields such as the medial prefrontal cortex and bilateral anterior STS. These regions have all been argued to fall within the social brain network [55].…”

Singers show enhanced performance and neural representation of vocal imitation.

“…An alternative possibility is that the larynx's intrinsic musculature may be represented neurally in a more fine-grained way linked to ongoing prosodic modulation rather than mean pitch. This argument is supported by recent work using electrocorticography in pre-surgical patients, in which the intonation contour of spoken sentences and sung phrases was tracked by high gamma activity of electrodes located in dorsal LMC [21].…”

“…For example, vocal size exaggeration is effective in changing listeners' evaluations of talker height [17], which may provide advantages in competitive situations. Furthermore, recent evidence on social trait expression has shown that talkers can volitionally modulate their speaking voice to generate exaggerated impressions of specific traits in naïve listeners [21]. Beyond the mere demonstration of vocal modulation in humans, it is of interest to investigate how this skill might vary across individuals.…”