Fetal and infant development of the sense of hearing
In a foetus of just four months, the auditory system is already fully developed and has reached its final size. From that point onwards the first auditory impressions are made. Sounds and resonants of the mother’s voice become associated with her disposition. Moods of the mother such as stress or senses of delight are directly transmitted to the embryo in a hormonal way so that the child learns in a very early stage, the correlation of sound and sentiment.
Over the first years of life, the child creates new and quite different patterns of hearing, which open up more and more levels of auditory awareness for spatial orientation.