Faces synchronize when communication through spoken language is prevented.

Abstract

Cooperating with another person requires communicating intentions and coordinating behavior. People often accomplish these tasks using spoken language, but verbal communication is not always available. Here, we test the hypothesis that, to establish successful cooperative interaction, people compensate for the temporary loss of one means, verbal communication, by amplifying another, namely nonverbal expressive synchrony. Fifty-seven female dyads, half of whom were prevented from using spoken language, completed four cooperative tasks, two of which induced expressions of emotion, while their faces were filmed. The no-language dyads displayed more facial-expressive synchrony, quantified using a novel application of multidimensional dynamic time warping. We find that solutions to coordinating interaction solved by spoken language can be compensated for by synchronizing facial expressions. The findings also point to one social force-the lack of shared language-that might, in the long-term, select for cultures of increased nonverbal expressiveness and synchrony.

How and Why People Synchronize: An Integrated Perspective

“…To create a time series of smiles during conversation, for instance, researchers might code the presence or absence of a smile as a discrete binary variable (Kellerman et al, 2020). Or, they might use electromyography (EMG), manual coding, or computer vision software to continuously quantify the degree of smiling (Golland et al, 2019;Hess & Bourgeois, 2010;Zhao et al, 2022). Likewise, signals from the heart can take the form of a continuous electrical signal measured with electrocardiogram (ECG), a continuous measure of heart rate (i.e., inter-beat interval), or, because the signal is biphasic, a discrete measure of whether the heart is in its diastolic or systolic phase .…”

“…In support of the idea that synchrony enables mutual understanding, research suggests that interaction partners increase lexical alignment following a misunderstanding (Fusaroli et al, 2017). Similarly, partners increase facial synchrony to compensate when they are prevented from using verbal communication to achieve mutual understanding (Zhao et al, 2022).…”

“…However, when perceivers are confronted with lags between vision and audition (in the case of badly edited videos), synchronization occurs to the modality that offers a better signal-to-noise ratio and greater temporal regularity (Bishop & Goebl, 2015). Furthermore, when language is prevented, dyads will engage in greater synchrony of facial expressions to compensate for the loss of the auditory modality (Zhao et al, 2022).…”

“…Compared to the previous decade (2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012), this decade (2013-2023) saw a three-fold increase in the number of psychology articles with "synchrony" in the title. 1 We now know that partners synchronize across a wide variety of behaviors (facial movements, gestures, speech, walking tempo; e.g., Jackson et al, 2018;Zhao et al, 2022), physiological markers (pupil dilation, heart rate, heart rate variability, skin conductance; e.g., Kang & Wheatley, 2017;Wilson et al, 2018), and even neural states (Wheatley et al, 2012). The tendency to synchronize, at least physiologically, may be somewhat stable within individuals and across contexts (Wohltjen et al, 2022).…”

Ancestral Diversity: A Socioecological Account of Emotion Culture

“…According to assigned condition, participants—who were not selected on the basis of cultural background—were permitted to or prevented from using spoken language to communicate during the study. The no-speaking condition modeled one feature of life in regions of extensive historical migration, namely the initial lack of common language (Zhao et al, 2023). Participants working in pairs took turns completing four tasks.…”