Brain to Brain Synchronization and the role of the shared semantics

Project Information

B2B-sync

Grant agreement ID: 840885

DOI

10.3030/840885

Project closed

EC signature date 11 April 2019

Start date 1 September 2019

End date 29 October 2021

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 224 933,76

EU contribution

€ 224 933,76

Coordinated by

THE CHANCELLOR MASTERS AND SCHOLARS OF THE UNIVERSITY OF CAMBRIDGE
United Kingdom

Periodic Reporting for period 1 - B2B-sync (Brain to Brain Synchronization and the role of the shared semantics)

Reporting period: 2019-09-01 to 2021-08-31

Summary of the context and overall objectives of the project

We spend our lives conversing with one other. The effectiveness of verbal communication has important social, economic, and educational consequences. It is essential to many important activities, including student–teacher and patient–clinician interactions. The two main constitutive parts of verbal communication are speech production and speech perception. Typically, they have been studied separately and with isolated individuals. Nevertheless, a speaker producing perfectly intelligible speech and a listener being able to decode it, are necessary but not sufficient elements for successful communication. We have all experienced failed conversations in which no clear understanding could be drawn from the information conveyed. Recently, some scholars have applied a ‘two-person neuroscience’ (2PN) framework to investigate the specific neural mechanisms underpinning speaker–listener interactions. This framework involves collecting simultaneous neural recordings from more than one person, a technique referred as hyperscanning. The results have revealed that effective verbal communication is associated with a pattern of inter-brain coupling. In other words, the brains of people having an effective conversation are literally ‘on the same wavelength.’ However, the role played by the inter-brain coupling of oscillatory activity, for the two persons to understand each other is still unknown. We propose a research agenda that aims at discovering the interplay between different aspects of verbal interaction and brain-to-brain coupling.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

First, we implemented electroencephalographic (EEG) hyperscanning configurations allowing a precise time-locking between the different brain recordings and sensory stimulation. Specifically, we implemented hardware configurations wherein the real-time delivered auditory stimulus is recorded jointly with ongoing EEG recordings.
With this customized implementation ready, we investigated inter-brain coupling lagged dynamics during speaking and listening. We also addressed the role of the interlocutors' joint brain entrainment to the speech envelope. We concluded that inter-brain coupling during speaking and listening cannot be explained only by joint entrainment to the speech envelope. Our results challenge the idea of a speech chain during verbal communications and instead indicate that inter-brain coupling occurs instantaneously.
In addition, we investigated for the electrophysiological markers of the cooperative interactions (opposite to competitive interactions). We concluded that prosocial intentions such as shared intentionality are expressed in an increased inter-brain coupling in the gamma frequency band.
Finally, we investigated the role of the linguistic alignment between interlocutors on inter-brain coupling and mutual understanding. Preliminary results suggest that inter-brain coupling reflects that a good listener is predicting the words and meanings that their communicative partner is trying to express.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Although the processes associated with successful communication are often considered intangible, inter-brain coupling has the potential to open the door to the biological assessment of effective communication. This project explored new forms of quantification of linguistic interactions within the context of relatively natural conversation. Overall, the project yielded a much richer theoretical understanding of the neural basis of verbal communication and the inter-brain coupling phenomenon. Moreover, it improved the data recording standards for EEG hyperscanning. Results obtained will have an impact beyond theories of verbal communication and into practical applications for clinical and educational environments.

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