SoundSpace Online

Auditory Development from Birth

The physical structures of the ear are already completely formed by the time a baby is born. The inner ear (cochlea) is completed and begins to hear at around 25 weeks’ gestation, and fetuses will respond to loud noises with an increased heart rate then. In fact, hearing sounds (especially human voices) in utero is important to stimulate the auditory pathways between the cochlea and the brain, and the auditory parts of the brain itself.

Although all structures in the auditory system develop very early in fetuses, they do not all develop at exactly the same time. Parents of children with conditions such as atresia often wonder how it is possible for their child to have a completely absent outer ear and ear canal, and yet the innermost part of the ear, the cochlea, can be formed and function completely normally. This is because different parts of the ear are formed from different kinds of fetal tissue, all of which develop at different times. It is entirely possible for something to disrupt the formation of one kind of tissue at a particular time (for example, the tissue that is supposed to grow into an ear canal), but the development of other kinds of tissue (for example, the cells that will grow into a cochlea) proceeds without a hitch.

It turns out that infants can perform an astonishing number of listening tasks successfully, such as being able to discriminate speech sounds from any of the world’s languages. Gradually, however, their auditory systems and brains learn to “tune in” to the spoken language(s) they hear every day. Please visit this Worth Publishers YouTube video on infant speech perception.