The Emotional Baby: How Infants Respond To Music

Have you seen the “emotional baby” video yet? At last count, 25 million people had viewed this YouTube clip of an infant smiling tearfully while her mother sings a bittersweet Rod Stewart ballad. While that’s only anecdotal evidence of music’s power, science also suggests that music taps into something deep inside the human brain even before we can talk.

To learn more about how babies respond to music, we interviewed Dr. Laurel Trainor, director of McMaster University’s Institute for Music and the Mind in Hamilton, Ontario. 

Can a baby really sense the emotions in a song?

In that video, we can’t be sure whether the infant was responding to the emotional content of the singing, the facial expressions of the mother, or to some other stimuli. It’s difficult to answer the question of whether infants truly understand the particular emotions in music. But we do know that young infants prefer certain types of musical sounds and vocalizations.

What kind of vocalizations? And how do you figure that when your study subjects can’t talk yet?

Preferences can be measured by letting an infant use the rate at which they suck on something to control which of two voices he or she gets to listen to. Such studies suggest that infants prefer happy voices over angry voices.

Infants also prefer what is called “infant-directed” singing. Around the world, caregivers sing to infants in a way that differs from most other kinds of singing—usually in a conversational style, with a lot of repetition, high in pitch, slow in tempo, and in a loving tone of voice. Infants prefer this over other styles of singing.

Do babies seem to have any innate musical preferences?

Yes, there appear to be some innate preferences or sensitivities. For example, when two musical tones are played together, infants prefer “consonant” combinations over “dissonant” ones, very similarly to adults.

What do you mean by dissonant tones?  

Musical tones typically have both a fundamental frequency—what we perceive as pitch—and harmonics, which are multiples of that base frequency. When the harmonics across two or more tones are close, but not identical, in frequency, it causes interference patterns which give rise to a sensation of beating or roughness. This is called dissonance. The ear is very mature at birth, so it’s not surprising that young infants are sensitive to this.

What other specific elements of music do babies respond to?

Infants can discriminate tempo. More impressively, they can recognize the same piece of music played at different tempos. And infants are very good pitch processors. They notice when the pitch contour (up/down pattern) of a melody is changed. They also notice when a wrong note is played.

Before 12 months of age, infants do not appear to have a sense of key. Adults who have grown up exposed to Western music find it much easier to detect a wrong note in a piece of music if it goes outside the notes of the melody’s key. This indicates that even musically untrained adults have implicit knowledge about what notes belong in a key. But young infants do not—they can detect wrong notes, but do equally well with notes that remain in the key or go outside it. In fact, in some cases infants are better than adults at detecting wrong notes that remain in the key.

Speaking of key, some people think that songs in a minor key sound sadder than those in a major key. Is that something that infants notice?

We know that infants can discriminate major from minor chords, but we don’t know exactly when they begin to associate major keys with happy, and minor keys with sad.

Also, that association depends on what you’re used to. Musical systems differ, just as languages differ, and the structure of scales, keys, and harmony in your native musical system is largely learned through passive exposure, like language. Music in major keys is much more common in Western tonality, and music in minor keys does tend to sound more sad to Western listeners. However, in some musical systems, the minor scale is the most common, and can sound happy to listeners who are accustomed to it.

Speaking of cultural differences, when do these develop? Are Western babies born preferring Western music?

No, young infants are sensitive to a diversity of music. A process of “perceptual narrowing” appears to take place during the infant’s first year. Western music tends to use very simple meters, such as in a march, in which every second beat is accented. However, many cultures use more complex meters, for example, accenting every fifth or every 7th note. Young Western infants are able to detect changes in both simple and complex meters. But by 12 months, Western infants are only able to do so for the simple meters found in Western music.

Is there any truth to the idea that listening to classical music is good for babies’ brain development? And along the same lines, does exposure to music in the womb have any effect?

There is no evidence that listening to classical music has any more benefit that listening to many other types of music. But whatever sensory experience infants have affects their brain development, and music is no exception. There are studies indicating that infants remember sounds experienced during the last couple of months before birth, although the hearing environment in the womb is very different—more like hearing under water.

Have you ever encountered a baby that doesn’t like any kind of music at all?

No, but of course that doesn’t meant that there isn’t one out there!

This interview has been edited and condensed.

Human Journey

I'm an associate editor at NGM, where I write and edit stories for both our print and digital editions.