Music is a powerful tool that can transport you into another world, even dreamland. Throughout history, people have used songs to soothe their kids, with the oldest lullaby recorded on a Babylonian tablet between 4,000 and 5,000 years ago. Human nature instinctively tells us to sing to children, but why does it help put them to sleep, and are there musical attributes that make a good lullaby?

The relaxing nature of music is well documented. Listening to a calming song can reduce cortisol levels, slow breathing, lower blood pressure, and decelerate heart rate.* Of course, children experience these effects, but lullabies seem to outshine the average listening experience, and the data backs this up. In a study of NICU babies who listened to Mozart’s instrumental lullabies versus those sung by their caregivers, the infants who heard their caregiver’s voice showed significantly more positive results.** There are a few suspected reasons for this phenomenon. Children look to the adults in their lives for emotional cues. When a caregiver is relaxed and singing, it signals to the child that they’re in a safe environment and can also relax — increasing the bond between parent and child. Trust and care are likely where most of the magic comes from, but classical conditioning may also play a part. A bedtime routine involving a lullaby can further reinforce sleep behavior, much like Pavlov’s dogs had watering mouths after the bell rang to signal mealtime.

Lullabies are special; however, is it because of the comfort of a caregiver, or is there more to it? Elements such as cadence work best in a soothing song, whereas language isn’t necessarily as important. In a study of American infants, US babies were played eight foreign lullabies and exhibited similar responses in relaxation even though the music was unfamiliar.*** In a similar study, French infants were put in a dull environment without toys or their parent(s). The babies listened to recordings of a Turkish lullaby, one version spoken and the other sung, and the children who listened to the song remained calm longer than the ones with the spoken recording.**** The repetitive nature of the music, coupled with the tone and tempo, gives lullabies the power to put children to sleep. Soft, slow songs in a major key that use gentle “rocking” rhythms do the trick best, but don’t worry; skill isn’t a factor. You can rest easy knowing babies don’t mind how well you can sing. A smiling face and affectionate tone are the “performance” aspects that make an infant happy. With that in mind, next time you continue the tradition of singing a lullaby, enjoy the magic of the moment and know that your child is content with your love and attention.

Sources

* https://petersonfamilyfoundation.org/music-therapy/science-music-therapy/

** https://pubmed.ncbi.nlm.nih.gov/35707055/

*** https://www.nature.com/articles/s41562-020-00963-z

**** https://www.edweek.org/teaching-learning/ask-a-scientist-do-lullabies-for-infants-really-work/2016/01