Michelsson K, Christensson K, Rothgänger H, Winberg J
Children's Hospital, University of Helsinki, Finland.
Acta Paediatr. 1996 Apr;85(4):471-5. doi: 10.1111/j.1651-2227.1996.tb14064.x.
During the first 1-2 h after birth crying occurs during separation from the mother and stops on reunion. In rats, such "separation distress calls" have distinct phonetic properties. We examined this early crying by sound spectrography in 29 healthy, full-term, vaginally delivered babies, randomly assigned either to be kept in a cot or to be placed in body contact with the mother during the 90 min following birth. The former babies cried almost 10 times more than the latter ones. The duration of the cry signal (the smallest element of a cry analysed by spectrography) in both groups was 0.8-09s; the melody contour was flat or slightly rising--falling with a fundamental frequency of around 500 hertz. The cry is provisionally characterized as a discomfort cry, elicited mainly by separation from the mother.
