The researchers would score the babies’ apparent pain on the Neonatal Infant Pain Scale (NIPS) using facial expressions, crying, breathing patterns, movement and alertness as indicators. The person doing the scoring would also wear noise-cancelling headphones, so they wouldn’t know whether the music was playing or not.

On the seven-point scale, the Mozart listeners scored an average of just under five, which dropped below three in the first minute. Babies who got the heel prick in silence scored almost seven, and took several minutes to get back below three.

“Music intervention,” the authors of the study concluded, “is an easy, reproducible, and inexpensive tool for pain relief from minor procedures in healthy, term newborns.” An earlier study had found similar results in premature babies, but this was the first to assess full-term infants. The researchers also studied predominantly non-white babies, unlike some earlier studies.

Numerous other researchers have looked at the painkilling effects of music in adults, with theories that listening to music stimulates an emotional response, engages our attention and activates sensory pathways that compete with those for pain. Still, the exact mechanism is not well understood.

As for the babies, the researchers noted that they did not compare Mozart with other types of music, which could be a topic for future studies. Will Mendelssohn or Motörhead provide the same salutary relief? Or is this merely a case of Amadeus ex machina?