Babies try harder to communicate if parents make direct eye contact

When a parent gazes into their baby’s eyes, both the parent's and the baby's brains will respond and synchronise with one another, preparing them for communication and making learning more effective, according to a new study.

Researchers from Cambridge University looked at the brainwave patterns of 36 babies using electroencephalography (EEG), which measures patterns of brain electrical activity via electrodes.

As well as finding that brainwaves synchronised when there was eye contact, they also found that babies made a greater effort to communicate, making more ‘vocalisations’, when the adult made direct eye contact. Babies that made longer vocalisations also had higher brainwave synchrony with the adult.

Dr Victoria Leong, lead author on the study said: “When the adult and infant are looking at each other, they are signalling their availability and intention to communicate with each other. We found that both adult and infant brains respond to a gaze signal by becoming more in sync with their partner. This mechanism could prepare parents and babies to communicate, by synchronising when to speak and when to listen, which would also make learning more effective.”

Studies in the past have shown that when a parent and a baby interact, various aspects of their behaviour can synchronise, including their gaze, emotions and heartrate, but little has been known up till now about whether their brain activity also synchronises.

Researchers compared the baby’s brain activity to that of the adult who was singing nursery rhymes to the baby. In the first of two experiments, the baby watched a video of an adult as she sang nursery rhymes. First, the adult, whose brainwave patterns had already been recorded, was looking directly at the infant. Then, she turned her head to avert her gaze, while still singing nursery rhymes. Finally, she turned her head away, but her eyes looked directly back at the baby.

The researchers found the baby’s brainwaves were more synchronised to the adults when the adult’s gaze met the baby’s, as compared to when her gaze was averted. Interestingly, the greatest synchronising effect occurred when the adult’s head was turned away but her eyes still looked directly at the infant.

In the second experiment, a real adult replaced the video. She only looked either directly at the infant or averted her gaze while singing nursery rhymes. This time, where there was mutual eye contact, both infants and adults became more synchronised to each other’s brain activity. This occurred even though the adult could see the infant at all times, and infants were equally interested in looking at the adult even when she looked away. The researchers suggest this shows that brainwave synchronisation isn’t just due to seeing a face or finding something interesting, but about sharing an intention to communicate.

Dr Sam Wass, who was also involved in the study, said: “We don’t know what it is, yet, that causes this synchronous brain activity. We’re certainly not claiming to have discovered telepathy! In this study, we were looking at whether infants can synchronise their brains to someone else, just as adults can. And we were also trying to figure out what gives rise to the synchrony.

“Our findings suggested eye gaze and vocalisations may both, somehow, play a role. But the brain synchrony we were observing was at such high time-scales – of three to nine oscillations per second – that we still need to figure out how exactly eye gaze and vocalisations create it.”

The study ‘Speaker gaze increases infant-adult connectivity’ was published in the Proceedings of National Academy of Sciences (PNAS).