Infants use eye contact with speakers to work out what to pay attention to and synchronize their brainwaves, helping them learn language, scientists in Cambridge and Singapore have shown.

Infants are surrounded by a vast range of stimuli that compete for their attention – sights, sounds, voices – and must somehow work out which things are worth paying attention to and learning from. To do this, they often rely on social cues – eye contact, 'baby speak' or someone calling their name, for example – but how this helps with learning is not clear.

Professor Victoria Leong and colleagues at the University of Cambridge, UK, and Nanyang Technological University (NTU), Singapore, have previously shown that when an infant and adult make eye contact, their brainwaves synchronize with each other.

Now, in a study published in Nature Communications, they have shown that eye contact helps the baby decide what is important, acting as a 'switch' to synchronize their brainwaves with those of the speaker and help them learn.

To do this, the team got infants in both countries to listen to three nonsense languages formed from triplets of syllables repeated over and over again. Each of these languages was paired with a speaker who appeared on a screen wearing glasses – in one setup, her glasses were clear; in a second, her glasses were partially shaded, making it more difficult to see her eyes; in the third, her glasses were dark, making it impossible to see her eyes. The same speaker was used for all three languages.

During the first part of experiment, when the infants were being familiarized with the languages, the team examined the infants' brainwaves using electroencephalography (EEG), which measures patterns of brain electrical activity via electrodes in a skull cap worn by the participants. 42 infants aged eight to 10 months from the UK and Singapore took part in this test. The researchers had also recorded the brainwave patterns of the speaker at the time of recording the videos while they spoke the languages. 

To test whether the infants had learned the language, the speaker then presented them with individual phrases from the different languages as well as new made-up words. Infants would be expected to spend more time looking at speakers who are using an unfamiliar language than one they were familiar with.

We let the infants listen to all three languages and it turned out they were selective in what they learned. They're not just passive sponges. They heard all three languages, but only learned the one, which was when they could see the speaker's eyes."

Professor Victoria Leong, School of Social Sciences at NTU and Department of Pediatrics, University of Cambridge

The researchers found that when a baby was learning the language, their brainwaves were more likely to be in sync with those of the speaker. In fact, the level of synchrony was more important for predicting learning even than the brain activity of the infants themselves. But crucially, brain activity was only synchronized when the baby could fully see the speaker's eyes.

The infants tended to look at the screen for the same amount of time, regardless of whether they could see the speaker's eyes, but eye contact was crucial for helping the baby determine which language was important.

Dr Kaili Clackson from the Department of Psychology at the University of Cambridge said: "Even when the infants seemed to be staring at a screen attentively, unless there was eye contact, nothing was going in – the information washed over them. The brain synchrony shows that it's a selection process."

The researchers found this phenomenon to be true in both Cambridge and Singapore, suggesting it is universal, not culture specific. However, in Singapore, infants spent more time in general looking at the speaker – possibly because the speaker's ethnicity was less familiar to them and hence more novel – though this did not affect learning.

Eye contact is one of the social signals that communicate intention to the listener. However, there are other social cues that do this, too, such as smiling, pointing and using the infant's name. These may be particularly important in cultures where eye contact between a child and adult is less important – or even frowned upon, as it is in some Arabic countries.

Dr Clackson added: "These cues are really powerful because when you preface new information with them, they tell the baby: this is important, you need to listen."

The researchers say they hope the findings will make parents more aware of the need to engage actively with their children.

"As parents, we need to be conscious of the need to use social cues like eye contact and calling your child's name, as these cues don't just focus your child's attention, they activate the learning process," said Professor Leong.

"If you're on your phone and distracted when you're trying to give them instructions or teach them something, there's less of a likelihood that they'll take it seriously or learn compared to if you put your phone down and look them in the eye. This is an important way of signaling your intentionality, your seriousness, that you want them to pay attention and learn something."

The research was supported by A*STAR and the Ministry of Education, Singapore.

Source:

Journal reference:

Zhang, W., et al. (2026). Adult-to-infant unidirectional neural coupling mediates selective social learning in infants from the United Kingdom and Singapore. Nature Communications. DOI: 10.1038/s41467-026-75831-x. https://www.nature.com/articles/s41467-026-75831-x