PRINCETON, N.J. — If you’ve ever played with a baby and felt like the two of you were communicating, in a way, without actually speaking it turns out you probably were on a neurological level. A new study conducted at Princeton University’s baby lab has found that infants and adults often share the same brain wavelengths during natural play. This means that both parties brain activity levels rise and fall together as toys are shared and eye contact is made.
“Previous research has shown that adults’ brains sync up when they watch movies and listen to stories, but little is known about how this ‘neural synchrony’ develops in the first years of life,” says first study author and associate research scholar Elise Piazza in a release.
Piazza and her fellow researchers believe this neural synchrony between babies and adults is important for infants’ social development and language skills.
Due to babies’ generally unpredictable behavior, it’s always been difficult for researchers to study interactions between infants and adults. In order to study these interactions in real-time, the research team for this study knew they had to develop a child-friendly method of simultaneously recording the brain activity of both a baby and an adult as they played together. So, they developed a groundbreaking new dual-brain neuro-imaging system. Besides just recording neural activity, this new system also keeps track of oxygenation in the blood, which serves as a proxy for neural activity.
This new invention allowed researchers, for the first time ever, to record neural coordination between baby and adult as the two played together (sang songs, played with toys, etc.)
For the research, one adult interacted with 42 different infants and toddlers. However, 21 of those babies had to be excluded from the study’s findings because they “squirmed excessively.” Additionally, another three babies refused to participate with the recording gear on their bodies. So, that left 18 babies in total, all ranging between 9 and 15 months old.
The experiment consisted of two parts. First, the adult played with each child for five minutes face-to-face while the baby sat on their parents’ lap. For the second portion, the adult turned away from the child and talked to another adult while the baby played silently with their parent. During all of this, the neural technology attached to both the adult and the babies recorded data from 57 different brain channels known to be involved in language, prediction, and understanding others.
After analyzing all of the recorded information, researchers noted that the babies’ brains were synchronized with the adult’s brain across several key areas while engaged in face-to-face play. Many of these brain areas are associated with “high-level” understanding of the world, possibly indicating that this neural connection helps infants better understand the toys, songs, stories, etc that they are seeing and hearing while playing with adults.
Conversely, when the adult and the baby were turned away from each other this neural connection disappeared completely.
Researchers also noted that they were surprised to see a great deal of these neural connections occurred in the babies’ prefrontal cortexes. This was unexpected because that brain area is thought to be largely underdeveloped during infancy.
“We were also surprised to find that the infant brain was often ‘leading’ the adult brain by a few seconds, suggesting that babies do not just passively receive input but may guide adults toward the next thing they’re going to focus on: which toy to pick up, which words to say,” comments co-author Casey Lew-Williams, an associate professor of psychology.
“While communicating, the adult and child seem to form a feedback loop,” Piazza adds. “That is, the adult’s brain seemed to predict when the infants would smile, the infants’ brains anticipated when the adult would use more ‘baby talk,’ and both brains tracked joint eye contact and joint attention to toys. So, when a baby and adult play together, their brains influence each other in dynamic ways.”
The study is published in Psychological Science.