Researchers from the University of Dundee in Scotland have found that newborns can respond to different emotions in music, falling asleep faster to cheerful songs.

Researchers measured the infants' heart rate and other behavioral indicators, which arose in response to cheerful and sad music, as well as its absence. It turned out that arousal levels decreased and sleep occurred most quickly when children were put on cheerful songs.

The emotional content of the music was confirmed with a preliminary experiment in which independent participants rated their mood from listening to well-known children's songs. 

The results of the experiment indicate that music therapy can be used as a calming or stimulating influence from the earliest days of life.