Brain-to-Brain Synchrony during Naturalistic Social Interactions

Sivan Kinreich,Amir Djalovski,Ruth Feldman,Yoram Louzoun,Lior Kraus

doi:10.1038/s41598-017-17339-5

Sivan Kinreich, Amir Djalovski + Show 3 more

Open Access

https://doi.org/10.1038/s41598-017-17339-5

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Abstract

The evolution of humans as a highly social species tuned the brain to the social world; yet the mechanisms by which humans coordinate their brain response online during social interactions remain unclear. Using hyperscanning EEG recordings, we measured brain-to-brain synchrony in 104 adults during a male-female naturalistic social interaction, comparing romantic couples and strangers. Neural synchrony was found for couples, but not for strangers, localized to temporal-parietal structures and expressed in gamma rhythms. Brain coordination was not found during a three-minute rest, pinpointing neural synchrony to social interactions among affiliative partners. Brain-to-brain synchrony was linked with behavioral synchrony. Among couples, neural synchrony was anchored in moments of social gaze and positive affect, whereas among strangers, longer durations of social gaze and positive affect correlated with greater neural synchrony. Brain-to-brain synchrony was unrelated to episodes of speech/no-speech or general content of conversation. Our findings link brain-to-brain synchrony to the degree of social connectedness among interacting partners, ground neural synchrony in key nonverbal social behaviors, and highlight the role of human attachment in providing a template for two-brain coordination.

Highlights

Humans are fundamentally socind the capacity to function competently within the social world shapes our physical health and emotional well-being throughout life[1,2,3]
Such neural synchrony was higher in romantic couples compared to strangers, indicating that human attachments may play a role in brain coordination and the degree of social connectedness among partners impacts brain coordination
Brain-to-brain gamma coupling was anchored in nonverbal social behavior; it was higher during moments of social gaze and marginally higher when individuals expressed positive affect

Summary

Introduction

Humans are fundamentally socind the capacity to function competently within the social world shapes our physical health and emotional well-being throughout life[1,2,3]. The search for mechanisms that enable two adults to coordinate their brain response in real life may profit from investigating natural social moments, focusing on romantic partners as a prototypical relationship that propagate synchrony, and anchoring neural synchrony in key nonverbal social behaviors that are learned within the first social dialogue between parents and infants, such as gaze and affect. Brain areas that support brain-to-brain neural synchrony may involve temporal-parietal structures, including the posterior superior temporal sulcus (pSTS) and temporo-parietal junction (TPJ), and studies using a variety of methods have pinpointed neural synchrony to these regions These studies have found that the degree of social connectedness among partners, as indexed by multiple factors such as familiarity, predictability, or collaboration, is associated with the level of neural synchrony. An animal study involving temporal and parietal cortices implicated gamma activity in the binding of sensory representations[37] and, in humans, audiovisual looming signals elicited increased gamma-band coherence between auditory cortex and the STS38, suggesting that gamma oscillations may provide a fast-paced template for the coordination of two brains

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