Speech from caregivers is important in molding an infant’s brain development. This is commonly known as “infant-directed speech” or “motherese.” A new study sheds light on how parents who chat to their infants help their children’s brain development. Scientists used imaging and audio recordings to link early language skills to caregiver speech, sending a message that parents can have a significant impact on their child’s linguistic development in ways that can be seen in brain scans.
A team lead by a neurodevelopment researcher at the University of Texas at Dallas has discovered some of the most solid evidence yet that parents who chat to their infants boost their babies’ brain development.
The researchers used MRI and audio recordings to show that caregiver speech influences newborn brain development in ways that benefit long-term language success. The study’s corresponding author is Dr. Meghan Swanson, assistant professor of psychology in the School of Behavioral and Brain Sciences.
“This paper is a step toward understanding why children who hear more words go on to have better language skills, and what process facilitates that mechanism,” Swanson said. “Ours is one of two new papers that are the first to show links between caregiver speech and how the brain’s white matter develops.”
This paper is a step toward understanding why children who hear more words go on to have better language skills, and what process facilitates that mechanism. Ours is one of two new papers that are the first to show links between caregiver speech and how the brain’s white matter develops.
Dr. Meghan Swanson
White matter in the brain allows communication between distinct gray matter regions of the brain, where information processing occurs.
The Infant Brain Imaging Study (IBIS), a National Institutes of Health-funded Autism Center of Excellence project involving eight universities in the United States and Canada, as well as clinical sites in Seattle, Philadelphia, St. Louis, Minneapolis, and Chapel Hill, North Carolina, was used in the study. Home language recordings were obtained at 9 months and again six months later, and MRIs were performed at 3 months, 6 months, and ages 1 and 2.
“This timing of home recordings was chosen because it straddles the emergence of words,” Swanson said. “We wanted to capture both this prelinguistic, babbling time frame, as well as a point after or near the emergence of talking.”
It’s long been known that an infant’s home environment – especially the quality of caregiver speech – directly influences language acquisition, but the mechanisms behind this are unclear. Swanson’s team imaged several areas of the brain’s white matter, focusing on developing neurological pathways.
“The arcuate fasciculus is the fiber tract that everyone learns in neurobiology courses is essential to producing and understanding language, but that finding is based on adult brains,” Swanson explained. “In these children, we looked at other potentially meaningful fiber tracts as well, including the uncinate fasciculus, which has been linked to learning and memory.”
The photos were utilized by the researchers to calculate fractional anisotropy (FA). This parameter for the freedom or limitation of water transport in the brain serves as a proxy for white matter development progress.
“As a fiber track matures, water movement becomes more restricted, and the brain’s structure becomes more coherent,” Swanson said. “Because babies aren’t born with highly specialized brains, one might expect that networks that support a given cognitive skill start out more diffuse and then become more specialized.”
Swanson’s team found that infants who heard more words had lower FA values, indicating that the structure of their white matter was slower to develop. The children went on to have better linguistic performance when they began to talk. The study’s results align with other recent research showing that slower maturation of white matter confers a cognitive advantage.
“As a brain matures, it becomes less plastic – networks get set in place. But from a neurobiological standpoint, infancy is unlike any other time. An infant’s brain seems to rely on a prolonged period of plasticity to learn certain skills,” Swanson said. “The results show a clear, striking negative association between FA and child vocalization.”
Sharnya Govindaraj, a cognition and neuroscience PhD student and member of Swanson’s Baby Brain Lab, said she was shocked by the findings at first.
“At first, we didn’t know how to interpret these seemingly contradictory negative associations.” “The entire concept of neuroplasticity and learning new things had to fall into place,” she explained. “It also matters a lot which ability we’re looking at, because something like vision matures much earlier than language.”
Swanson was curious on how this link works for newborns exposed to more than one language as the parent of a toddler in a multilingual family.
“Raising a bilingual child, it’s remarkable how she’s not confused by languages, and she knows who she can use which language with,” Swanson said. Swanson also expressed a greater appreciation and thanks for what she, as a researcher, expects parents to perform in her studies.
“When participants sign up, I’m asking them to commit to a year and a half,” she explained. “Because of all the parents’ commitment to prior studies, I and others now have the knowledge that allows us to communicate with our children in a way that supports their development.”
The take-home lesson, according to Swanson, is that parents have the ability to assist their children develop.
