Infants' innate ability to tune into musical rhythms is intertwined with early social engagement

Infants' innate ability to tune into musical rhythms is intertwined with early social engagement

According to a study published by the Proceedings of the National Academy of Sciences, engaging infants with a song provides a ready-made means of supporting social development and interaction.

Researchers from Vanderbilt University Medical Center (VUMC), Marcus Autism Center, Children's Healthcare of Atlanta and Emory University School of Medicine enrolled 112 infants who were either 2 months or 6 months old.

The study tracked infants' eye gaze from moment to moment to show that the rhythm of caregivers' singing causes the infant's eye gaze to become synchronized, or entrained, to caregivers' social cues on time scales of less than a second.

As early as 2 months of age, when infants first interact interactively with others, infants were twice as likely to look into the singers' eyes timed to the musical beat than would be expected by chance.

At 6 months of age, when infants are highly adept at face-to-face musical play and developing increasingly sophisticated rhythmic and communicative behaviors such as babbling, they were more than four times as likely to look into the eyes of singers in sync with musical beats.

Singing seems like such a simple act to toddlers, but it is full of rich and meaningful social information. Here we show that when caregivers sing to their infants, they intuitively structure their behavior to support caregiver-infant social bonding and infant social learning.”

Miriam Lense, PhD,Lead author of the study,Assistant Professor of Otolaryngology and Co-Director of the Music Cognition Lab at VUMC

During the tests, researchers used eye-tracking technology to measure every movement of each infant's eyes while they watched videos of people engaging them with songs.

"For this study, we used singing videos instead of live singing to ensure that any change in the infant's appearance was due to the child and not the singer's adaptation to the child," Lense said. “Toddlers could look anywhere while watching the videos, but we found that their looking behavior was not random.”

"The predictable rhythm of singing is critical to this entrained social interaction. If we experimentally manipulate singing so that it no longer has a predictable rhythm, entrainment is disrupted and infants no longer successfully synchronize their gaze with caregivers' social cues," she added.

The researchers confirmed their findings in another group of 6-month-old infants who watched both the original videos of singing and videos that had been manipulated to make them jitter so that their rhythms were no longer predictable.

While the infants again showed enthralled looks at the original videos when singing was rhythmically predictable, this time-locked eye gaze effect was no longer present when the predictable rhythm was disrupted.

"This is important because it reveals a remarkable physical coupling between the caregiver's behavior and the infant's experience," said Dr. Warren Jones, senior author of the study and Nien Distinguished Chair in Autism at Emory University School of Medicine. “Without conscious awareness, something as simple and intuitive as the caregiver singing sets in motion a cascade of behaviors that alter infants’ experiences.”

“Although what a caregiver expresses is important, when and how they express social cues is particularly important to infant-caregiver communication,” Lense added. “Rhythmic predictability – a universal feature of song – is an integral mechanism for structuring social interactions and supporting infant social development.”

Reyna Gordon, PhD, associate professor of otolaryngology and co-director of the Music Cognition Lab at VUMC, said the study underscores that making music is not just about entertainment: Making music is a central aspect of early socio-emotional development.

"It's remarkable that these infants are essentially tracking the beat of the music with their eyes, modulating their eye contact with the singer's eyes around the beat (or pulse) of the singing," said Gordon, who was not involved in the study.

"These results represent a major advance in our understanding of the extent to which very young children are sensitive to musical rhythms, suggesting that innateness for music is intertwined with early social engagement," she added.

The study was funded by the National Institutes of Health (National Institute of Mental Health, National Center for Complementary and Integrative Health, National Institute for Deafness and Communication Disorders) and the GRAMMY Foundation.

Lense said her team has now expanded the research to examine synchronization in autism as part of the Sound Health Initiative, a partnership between the National Institutes of Health (NIH) and the John F. Kennedy Center for the Performing Arts in collaboration with the National Endowment for the Arts.

Source:

Vanderbilt University Medical Center

Reference:

Hannon, E.E., et al. (2022) Tuning into musical rhythms: Toddlers learn more easily than adults. PNAS. doi.org/10.1073/pnas.0504254102.

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