When two people talk to each other, their brain activities synchronise. However, a new study by Perez et al at the Basque Centre on Cognition, Brain and Language, in Donostia, Spain, has found that two brains synchronise differently, depending on the language being used, and regardless of non-verbal communication.
Synchrony between two people engaged in communicating operates at several levels. The verbal and non-verbal signals interact with emotional cues to facilitate bonding between the communicators, whether they are well-known to each other, such as parent and child – or in this case – complete strangers.
Perez focussed on purely verbal communication with no visual input and measured the pattern and amplitude of the speaker’s brain waves. Generally, as speakers converse, their brains’ activity becomes synchronised.
This both allows and reflects increasing mutual comprehension, and so Perez tested whether conversing in a second language (which might decrease understanding) might affect the way the two interacting brains synchronise with each other.
Perez put 60 native Spanish speakers with basic fluency in English into pairs, separated by a screen. They were given topics and question prompts: 3 in English only and 3 in Spanish only. Throughout their conversations, their brain activity was measured (as the distribution and amplitude of alpha, beta and theta waves).
As expected, the speakers’ brains’ activity synchronized as they conversed – but the synchronisation was not only less, but also showed a different pattern, when talking in English rather than Spanish. The decreased level of synchronization was not unexpected and is likely due to the increased attention required to track speech in a second language.
The different pattern of brain activity depending on the language spoken is a novel finding that adds to the debate on whether neural correlates of language use are more general or more specific.
Follow-up questions revealed no apparent differences in general intelligibility, and Perez suggests that it may be more specific differences in, for example, phonetic, phonological, lexical, syntactic or semantic tracking that leads to different patterns of brain activity.
It may be that neural activation patterns depend on the specific language system in use. For example, the phonological and physical processes that produce or comprehend the English word ‘snake’ will be different to the Spanish word ‘serpiente’, despite the two being semantically equivalent.
Consequently, different parts of the brain will be activated depending on which language is being spoken or heard.
Brain synchronisation relates not only to mutual comprehension but also to empathy, and Perez’s study prompts the question, ‘Can two people ever reach their full potential for mutual understanding and empathy when one or both are conversing or negotiating using a second language?’
Perez’s findings also have potential practical implications for developing methods to assess the quality of communication in many situations, including language practice, for example by using feedback from speech and brain activity sensors in headphones.
REFRENCE
■ Perez, A., Dumas, G., Karadag, M. and Duñabeita, J. A. (2019) ‘Differential brain-to-brain entrainment while speaking and listening in native and foreign languages.’ Cortex, 111: 303-315.
