What makes a baby smile? In 2016, British musician Imogen Heap teamed up with psychologists to turn that question into a song. Ten years later, The Happy Song has surpassed 470 million Spotify streams.
Released on Oct. 17, 2016, the track emerged from a collaboration with developmental psychologist Caspar Addyman and music psychologist Lauren Stewart at Goldsmiths, University of London. The team combined research into babies’ responses to music with suggestions from thousands of parents to create a melody filled with playful sounds and affectionate lyrics.
The result became an unexpected hit with families with young children, offering a glimpse of what happens when scientific research informs a creative project.
How a scientific experiment became a song
The project began when C&G Baby Club — a parent network backed by British baby food brand Cow & Gate — commissioned Addyman and Stewart to create a scientifically informed song designed to make babies happy.
The researchers first asked nearly 2,300 parents across the United Kingdom to identify sounds that made their babies cheerful. The most frequently reported included sneezing, animal noises and baby laughter. Those responses gave the team a collection of ideas to incorporate into the composition.
Heap, a Grammy-winning British musician, took on the musical challenge. She also had a young audience member at home: her daughter, Scout, who was 18 months old during the project.
The researchers provided Heap with recommendations based on previous studies of infant musical preferences. They suggested a major key, a simple, repetitive melody, an energetic female voice, and musical changes that could create anticipation and surprise.
Heap composed four short melodies with different tempos, chord patterns, pitches and rhythms. She also prepared versions with and without simple lyrics so researchers could compare babies’ responses.
The aim was to create something that appealed to infants while remaining enjoyable for adults. Heap built the final lyrics around an affectionate message, taking listeners on an imaginative journey through the sky, the ocean and trips by bicycle, submarine and rocket.
What testing babies revealed
Addyman described the experiment in a 2017 article originally published by The Conversation and later republished by Live Science. The initial laboratory test included 26 infants aged 6 to 12 months.
The infants listened to eight short pieces based on the four melodies. Researchers filmed their reactions and examined the recordings for smiles, laughter and dancing. They also asked parents which versions they believed their babies preferred.
Twenty of the 26 babies appeared to favor the same melody. That result gave the team a starting point for developing the full song.
The researchers then tested variations of the composition. One finding challenged their initial expectations about tempo.
Because babies have faster heart rates than adults, the team expected a faster song to appeal to them. However, a tempo of 163 beats per minute resonated more strongly than 168 beats per minute. The researchers also identified the chorus as the most effective section and adjusted the lyrics and sound effects.
Goldsmiths reported that the wider development process involved monitoring more than 50 babies, including their facial expressions, movements, heart rates and vocalizations. The university described the project as an eight-month process from the first ideas to the finished recording.
Not every measurement worked as planned. Addyman noted that measuring heart-rate changes and tracking whether the babies moved in sync with the music presented technical challenges. He described the research as useful pilot work and identified further studies as a possible next step.
The experiments helped the team select a melody and refine the song, although they did not establish that it could reliably stop crying or soothe every child.
Why parents keep listening
The finished track combines a bouncing melody, playful sound effects and lyrics designed to encourage interaction between babies and their caregivers. Its appeal rests partly on how it invites parents to sing, move and play with their children.
Heap also hoped the song would help parents through everyday situations. Speaking to CNN, she said that giving families a few minutes of relief during difficult moments — such as being stuck in traffic — was a primary goal. By its 10th anniversary, the track had logged more than 470 million Spotify streams, alongside a 10-hour YouTube loop with roughly 14 million views, illustrating how widely families have incorporated the song into their daily routines.
Independent tracking estimated the Spotify total at 478.7 million streams. Ultimately, these numbers reflect the song’s vast audience rather than its specific psychological effect on individual babies.
Developed as a musical experience rather than a medical intervention, The Happy Song is not an approved treatment, nor did its initial studies establish clinical efficacy.
For parents, the song remains one option for sharing music and play with a young child. Babies respond differently to sounds, and persistent crying may have causes that a song cannot address.
A decade after its release, The Happy Song has become a striking example of collaboration between music and science. The research explains how its creators developed the track; its streaming success shows how widely audiences have embraced it. Whether it brings a smile to a particular baby is still something each family has to discover.