The Fascinating History and Science of Why Lullabies Work

As a parent, you’ve likely played soft, relaxing songs as you get your kids ready for bed, or perhaps you’ve sung your favorite childhood lullaby as you rock your baby to sleep. There’s a scientific basis for why these soothing songs are so effective.

Throughout history, parents have used lullabies to promote bonding with and soothe their children, and they’re just as relevant today. Experts say lullabies are also a great tool for creating a sleep-inducing bedtime routine for your little one. Below, learn more about the importance of lullabies across time and cultures, and how you can use singing and music to promote better sleep for your little one.

The science of lullabies 

Softly singing a song to promote a calming response before bed works for several reasons. For one thing, any night-time routine — a warm bath, rocking, dim light — can be useful in creating associations between those activities and sleep. Over time, these cues can reinforce sleep as a behavior.

A Tip From Hatch: Lullabies are the perfect way to soothe babies while introducing them to a wide variety of styles and musical patterns including rhythm, rhyme, and melody. Hatch’s all-new Tiny Bed Concerts give parents special songs they can share with their babies. 

Lullabies in particular involve several cues that can be comforting to a baby, says Jade Wu, Ph.D., a behavioral sleep psychologist, researcher at Duke University School of Medicine, and Hatch medical advisor. Lullabies mimic the lilting rhythms of speech and sounds the baby might have heard in the womb, which can be comforting, explains Dr. Wu. A soothing song also sends a signal to your baby that the environment is safe. “To have good sleep, your body needs to feel safe and relaxed,” she says. “Lullabies signal your caregiver is close and relaxed, and if your caregiver is relaxed, there must not be danger.” 

Snuggling your baby while singing a lullaby can also promote the release of the hormone oxytocin, the so-called “love” hormone that Dr. Wu says promotes a sense of well-being, safety, and relaxation. Any calming music in the background can add a calming element to the bonding, but singing, specifically, can be helpful. “Your body vibrates as you sing, which is soothing for the baby, just like a vibrating swing,” says Dr. Wu. 

Recent research from Harvard has also found there’s something inherently soothing about lullabies, even if a baby has never heard a particular song before. In a recent study, Harvard researchers played lullaby songs from several cultures around the world in different languages, including Scandinavian, Mayan, Inuit, and Gaelic, along with non-lullaby songs from various cultures, then measured the infants’ responses to each song.

They found that infants calm down in response to lullabies from other cultures they’ve never heard, which suggests the music humans across cultures have written to soothe their babies has particular qualities conducive to calm. 

Put another way, people across time and culture evolved to sing lullabies with distinctly soothing traits. “These regularities reflect that there is something predisposed in the human mind and psychology that guides why music sounds the way it does,” says researcher Mila Bertolo, a Ph.D. student studying the origins of music at McGill University in Montreal.

There’s a whole area of research dedicated to the sonic components of effective lullabies. Some of the most common components include slow, soothing melodies that mimic the motion or feeling of being rocked, along with references to sleep and being held. For example, “Rockabye Baby” has a slow tempo of just over 100 beats a minute and cozy lyrics about being gently rocked.

Other research has found children can recognize when a song is a lullaby because of how it sounds, even if the lyrics are in a foreign language. So there’s reason to believe lyrics matter less than the music aspects — and add in the comfort of being held by a secure attachment figure, and you’ve got a pretty reliable recipe for peaceful slumber. 

A Tip From Hatch: Check out Tiny Bed Concerts from Hatch, a music collection that features artists playing covers of popular children’s songs and lullabies with a special spin.

How to incorporate lullabies into your routine 

If you’re looking to start a sleep routine with your little one, lullabies are an accessible, easy-to-implement intervention. While much of the research focuses on mothers and babies, Dr. Wu says any parent or caregiver can use lullabies to soothe a child. Playing music helps, and singing the lullaby can add a layer of comfort to a dozing child. Don’t worry if you’re not a pro singer; your baby’s familiar with and has been relaxed by your voice since before they were born. 

Lullabies can be used when your baby is upset or crying, but they may be more effective in helping promote positive sleep behaviors when your baby is already calm. 

In a 2023 study, researchers found when mothers sang their babies lullabies as a “reward” for calm and quiet, crying decreased and maternal-child bonding increased. “They learned that every time they were in that state, they could get music,” says Amy Robertson, Ph.D., director of music therapy and associate professor of music education and therapy at the University of Missouri-Kansas City.

While Robertson’s study used familiar lullaby melodies with personalized lyrics, what you sing isn’t as important as how you engage with your baby. But if naptime or bedtime are particularly dicey, you could consider using different songs as part of each routine — for example, you could sing or play “Rockabye Baby” before naptime and “You Are My Sunshine” in the evening, before bed. “Otherwise, the baby might begin to associate one song with a more difficult bedtime,” says Dr. Wu. 

And no matter how you incorporate music, remember babies thrive on routines. Any cue that leads to a predictable outcome, such as dimming the lights, turning on a sound machine, or putting on pajamas, can help prepare your child for bedtime — and hopefully, make the experience less stressful for you as a parent.