Lullabies are frequently not comforting

Lullabies are among the most universal musical forms. They are documented in essentially every society examined, and they share features across traditions that are otherwise musically unrelated.

The shared musical features

Studies comparing lullabies across many cultures have found consistent characteristics: slow tempo, narrow melodic range, repetition, descending phrases, simple rhythm, and a particular vocal quality — softer, breathier and with a distinctive timbre.

Listeners can identify lullabies from unfamiliar traditions at above-chance rates, which suggests the features are recognisable independent of cultural knowledge.

Infants respond to them, and there is reasonable evidence that infant-directed singing reduces arousal, which is presumably the point.

The rocking rhythm is close to universal, and the correspondence between the tempo of many lullabies and the pace of walking or rocking is not likely to be coincidental.

The words are another matter

Collect lullaby texts and the content is startling.

They contain threats, warnings about creatures that take children, references to the death of the child or the singer, accounts of poverty and hunger, complaints about husbands and in-laws, expressions of exhaustion and, not infrequently, of resentment toward the child.

This has been documented across a very wide range of traditions and it is not an anomaly in a handful of them.

Why

Several explanations, and they are not exclusive.

The infant does not understand the words. The soothing is done entirely by the melody, the rhythm and the voice, which frees the text to be about anything.

It is one of the few permitted outlets. In societies where a young woman has little standing and few opportunities to voice complaint, singing alone to a baby is unobserved and unaccountable. Lullaby texts in several traditions constitute one of the more direct records of what women thought about their circumstances.

Collectors have noted this repeatedly — that the lullaby repertoire of a region contains material found nowhere else in its oral tradition, because nowhere else could it be said.

Exhaustion is real. A great deal of lullaby text is straightforwardly about wanting the child to go to sleep so the singer can too, expressed with a frankness that is usually funny and occasionally not.

Protection. Some traditions include warnings and protective formulas, addressing the beings believed to threaten infants. In that context a frightening text is a defensive measure rather than a lapse.

Preparing for loss. In conditions of high infant mortality, songs that acknowledge the possibility of the child dying are a way of holding something that could not otherwise be spoken about.

The transmission

Lullabies are learned from being sung to and passed on largely unchanged, which makes them unusually conservative.

They frequently preserve archaic vocabulary, older grammatical forms and melodic patterns that have disappeared from the rest of a tradition's music. Singers often do not know what particular words mean and sing them anyway because that is how the song goes.

That conservatism makes them valuable to researchers, and it is fragile in the usual way — a single generation not singing to their children breaks it.

What is replacing them

Recorded music, white noise machines and lullaby playlists.

These provide the acoustic properties and not the interaction. Whatever the effect of live singing is — and there is reasonable evidence that infant-directed live singing does something recordings do not, involving mutual responsiveness between singer and child — a recording does not do it.

There is also a smaller and specific loss: the singer's own repertoire, learned from their parent, which is a piece of continuity that a playlist does not carry.

The one thing worth saying to anyone with a baby

Singing quality is irrelevant. Infants do not have an opinion about pitch accuracy, and there is no evidence that a poor singer produces a worse effect.

What matters is the voice being familiar, the tempo being slow, and the interaction being live. Everything else is decoration.

And if the words that come out are about how tired you are and how you would like this to stop — that is squarely within the tradition, and there are several thousand years of precedent.