Brainwaves of mothers and children synchronize when playing together – even in an acquired language

(Press-News.org) Interbrain synchrony is the simultaneous activity of neural networks across the brains of people who are socially interacting –- for example talking, learning, singing, or working together. Having brains that are thus synchronized or ‘in tune’ can help people boost their emotional connection, improve communication, and align their attention.

Neural synchrony is thought to be important for healthy bonding between parents and children. And now, a team of scientists in the UK has found that neural synchrony doesn’t appear to get ‘lost in translation’. The results are published in Frontiers in Cognition.

“Here we show that the brains of bilingual moms and their kids stay just as ‘in sync’ through neural synchrony irrespective of whether they play in the mom’s native language or in an acquired second language,” said first author Dr Efstratia Papoutselou, a research fellow at the School of Medicine of the University of Nottingham.

“This is an important finding because it suggests that using a second language doesn’t disrupt the brain-to-brain connection that supports bonding and communication.”

Many children around the world are raised in families where more than one language is spoken. For example, in the EU the percentage of such ‘mixed households’ increased from 8% to 15.6% between 2014 and 2023. The social, cognitive, and academic benefits of growing up with more than one language are obvious. But Papoutselou and colleagues wanted to know if multilingualism might pose a handicap when it comes to parent-child communication and bonding. The reason: even highly proficient speakers tend to speak an acquired language slower with more pauses and corrections, especially in emotionally charged or cognitively demanding contexts.

“Second-language speakers often report a sense of emotional distancing when using their non-native language, which may influence how they express affection, discipline, or empathy in parent-child interactions,” wrote the authors.

Brain power

The researchers focused on 15 families in the UK where children between three and four years old had been raised bilingually. English was not the mothers’ first language but learned at C1 or C2 level according to the Common European Framework of Reference for Languages.

Each mother-child pair visited the research clinic and sat at a table with toys. Both wore a fNIRS (functional near-infrared spectroscopy) cap to measure change in the oxygen concentration across the brain’s blood vessels – a proxy for neural activity. They were instructed to play naturalistically according to one of three scenarios in randomized order: together in the mother’s native language as at home, together exclusively in English, or silently and independently from each other with a screen in between.

The fNIRS measurements showed statistically significant neural synchrony between each mother-child pair, which was stronger during interactive than during independent play. Synchrony was especially strong in the brain’s prefrontal cortex, a hub for decision-making, planning, reasoning, and emotions. It was weaker in the temporo-parietal junction regions which regulate social cognition and attention.

Two minds moving as one

The results showed that brain synchrony was equally strong when participants played in English as when they played in the mother’s native language.

The researchers concluded that talking in an acquired language didn’t impinge on a mom’s ability to synchronize her brain activity with that of her child during interactive play. These results suggest that this key condition for effective learning and bonding can be met irrespective of language.

“Bilingualism is sometimes seen as a challenge but can give real advantages in life. Our research shows that growing up with more than one language can also support healthy communication and learning,” concluded Dr Douglas Hartley, a professor at the NIHR Nottingham Biomedical Research Centre and the study’s senior author.

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