Hearing is one of the later senses to develop. It seems to start at 23 weeks gestation. The first responses to sound at the brainstem
level are around 24 weeks gestation. The
structures for hearing continue to develop between the ages of 24 and 34 weeks
gestation.
It has been noted that babies do hear while still in utero.
When babies are born, they seem to recognize their mother’s voice. Dr. Barry
Brazelton used to do an exercise with babies that were hours old. He would hold
the baby between its mother and another person and ask both to speak at the
same time. The baby would invariable turn towards its mother’s voice. He did
the experiment with the father as well and the babies overwhelmingly turned
towards their father over a stranger. The uterus is a noisy environment however
and sound must travel through liquid as well as distractions so the baby
probably hears a more distorted sound from outside while hearing the mother’s
voice from inside. Babies in utero respond to different types of music
according to research indicating that it may be worthwhile to play music to the
developing baby. At birth, the hearing system is in place though babies are
better able to hear higher frequencies at first, which may also account for
their higher receptiveness to a female voice. The ability to recognize the
meanings of sounds comes with experience so the system continues to develop
after birth as well. There is research that shows that babies are tuned to the
sounds of language and music over random noise sounds. They listen more acutely and for longer to
organized sounds than to random sounds according to studies. There is no
question that babies learn to speak by what they are hearing. This accounts for
the fact that children use the same accents of those around them.
Again, as with other senses, the structures in the ear may
be damaged or may just wear out as one becomes older and we find many elderly
people needing assistance to hear.
