Bursts of high-frequency activity in the babies' brains occur when the infants attempt to pay attention while playing with objects. But, when an adult engages in a joint-play with the infant, their brains show similar bursts of high-frequency, reveals new research — these bursts linked to attention pattern of the baby and not their own.

The authors simultaneously recorded electroencephalography (EEG) data from 12-month-old infants and their mothers when they were playing separately or together with toys. "Most infants spend the majority of their waking hours in the company of others. But almost everything we know about early learning in the brain comes from studies looking at individual baby brains in isolation," said Dr Wass, lead author on the study. "By recording activity in a baby's brain and their mother's brain at the same time, we were able to see how changes in their brain activity reflected their own or each other's behavior while they were playing together."

"We know that, when an adult plays jointly together with a child, this helps the child to sustain attention to things," he continued. "But until now we haven't really understood why this is. Our findings suggested that, when a baby pays attention to things, the adult's brain tracks and responds to her infant's looking behavior - as if her infants' actions are echoed in the parent's brain activity. And we also found that, where the parent's brain is more responsive to the child, the child sustains their attention for longer."