Speech and music are the dominant elements of an infant’s auditory environment. While past research has shown that speech plays a critical role in children’s language development, less is known about the music that infants hear.

A new 91Ě˝»¨ study, published May 21 in , is the first to compare the amount of music and speech that children hear in infancy. Results showed that infants hear more spoken language than music, with the gap widening as the babies get older.

“We wanted to get a snapshot of what’s happening in infants’ home environments,” said corresponding author , a 91Ě˝»¨research assistant professor of speech and hearing sciences. “Quite a few studies have looked at how many words babies hear at home, and they’ve shown that it’s the amount of infant-directed speech that’s important in language development. We realized we don’t know anything about what type of music babies are hearing and how it compares to speech.”

Researchers analyzed a dataset of daylong audio recordings collected in English-learning infants’ home environments at ages 6, 10, 14, 18 and 24 months. At every age, infants were exposed to more music from an electronic device than an in-person source. This pattern was reversed for speech. While the percentage of speech intended for infants significantly increased with time, it stayed the same for music.

“We’re shocked at how little music is in these recordings,” said Zhao, who is also the director of the Lab for Early Auditory Perception (LEAP), housed in the Institute for Learning & Brain Sciences (I-LABS). “The majority of music is not intended for babies. We can imagine these are songs streaming in the background or on the radio in the car. A lot of it is just ambient.”

This differs from the highly engaging, multi-sensory movement-oriented music intervention that Zhao and her team had . During these sessions, music played while infants were given instruments and researchers taught caregivers how to synchronize their babies’ movement with music. A control group of babies then came to the lab just to play.

“We did that twice,” Zhao said. “Both times, we saw the same result: that music intervention was enhancing infant’s neural responses to speech sounds. That got us thinking about what would happen in the real world. This study is the first step into that bigger question.”

Past studies have largely relied on qualitative and quantitative parental reports to examine musical input in infants’ environments, but parents tend to overestimate the amount they talk or sing to their children.

This study closes the gap by analyzing daylong auditory recordings made with Language Environment Analysis (LENA) recording devices. The recordings, originally created for a separate study, documented infants’ natural sound environment for up to 16 hours per day for two days at each recording age.

Researchers then crowdsourced the process of annotating the LENA data through the citizen science platform. Volunteers were asked to determine if there was speech or music in the clip. When speech or music was identified, listeners were then asked whether it came from an in-person or electronic source. Finally, they judged whether the speech or music was intended for a baby.

Since this research featured a limited sample, researchers are now interested in expanding their dataset to determine if the result can be generalized to different cultures and populations. A follow-up study will examine the same type of LENA recordings from infants in Latinx families. Since audio recordings lack context, researchers are also interested in when music moments are happening in infants’ lives.

“We’re curious to see whether music input is correlated with any developmental milestones later on for these babies,” Zhao said. “We know speech input is highly correlated with later language skills. In our data, we see that speech and music input are not correlated — so it’s not like a family who tends to talk more will also have more music. We’re trying to see if music contributes more independently to certain aspects of development.”

Other co-authors were , former 91Ě˝»¨undergraduate honors thesis student and incoming master’s student in clinical research speech-language pathology; , LEAP research assistant/lab manager; and , assistant professor of linguistics and adjunct research professor for I-LABS. This study was funded by the National Institute on Deafness and Other Communication Disorders of the National Institutes of Health.

For more information, contact Zhao at zhaotc@uw.edu.

Rock your baby in sync with music and you may wonder how the experience affects her and her developing brain.

A new by scientists at the 91Ě˝»¨’s Institute for Learning & Brain Sciences (I-LABS) shows that a series of play sessions with music improved 9-month-old babies’ brain processing of both music and new speech sounds.

“Our study is the first in young babies to suggest that experiencing a rhythmic pattern in music can also improve the ability to detect and make predictions about rhythmic patterns in speech,” said lead author , a postdoctoral researcher at I-LABS.

“This means that early, engaging musical experiences can have a more global effect on cognitive skills,” Zhao said.

The Proceedings of the National Academy of Sciences published the study this week.

“Infants experience a complex world in which sounds, lights and sensations vary constantly,” said co-author , co-director of I-LABS. “The baby’s job is to recognize the patterns of activity and predict what’s going to happen next. Pattern perception is an important cognitive skill, and improving that ability early may have long-lasting effects on learning.”

Like music, language has strong rhythmic patterns. The timing of syllables helps listeners define one speech sound from another and understand what someone is saying. And it’s the ability to identify differences in speech sounds that helps babies to learn to speak.

The I-LABS researchers designed a randomized-controlled experiment to see if teaching babies a musical rhythm would help the babies with speech rhythms.

Over the course of a month, 39 babies attended 12 15-minute play sessions in the lab with their parents. In groups of about two or three, the babies sat with their parents, who guided them through the activities.

In the 20 babies assigned to the music group, recordings of children’s music played while an experimenter led the babies and their parents through tapping out the beats in time with the music.

All the songs were in triple meter — like in a waltz — which the researchers chose for being relatively difficult for babies to learn.

The 19 babies in the control group attended play sessions that did not involve music. Instead, they played with toy cars, blocks and other objects that required coordinated movements without music.

“In both the music and control groups, we gave babies experiences that were social, required their active involvement and included body movements — these are all characteristics that we know help people learn,” Zhao said. “The key difference between the play groups was whether the babies were moving to learn a musical rhythm.”

Within a week after the play sessions ended, the families came back to the lab so the babies’ brain responses could be measured. The researchers used (MEG) to see the precise location and timing of brain activity.

While sitting in the brain scanner, the babies listened to a series of music and speech sounds, each played out in a rhythm that was occasionally disrupted. The babies’ brains would show a particular response to indicate they could detect the disruption.

The researchers focused their analyses on two brain regions, the auditory cortex and the prefrontal cortex, which is important for cognitive skills such as controlling attention and detecting patterns.

Babies in the music group had stronger brain responses to the disruption in both music and speech rhythm in both the auditory and the prefrontal cortex, compared with babies in the control group.

This suggests that participation in the play sessions with music improved the infants’ ability to detect patterns in sounds.

“Schools across our nation are decreasing music experiences for our children, saying they are too expensive,” Kuhl said. “This research reminds us that the effects of engaging in music go beyond music itself. Music experience has the potential to boost broader cognitive skills that enhance children’s abilities to detect, expect and react quickly to patterns in the world, which is highly relevant in today’s complex world.”

Funders of the research were the National Science Foundation 91Ě˝»¨LIFE Center, the Ready Mind Project at I-LABS, and the Washington State Life Sciences Discovery Fund.