This was earlier than previous estimates and occurs about two months before completion of the ear, suggesting that there is more to hearing than the ear alone. Babies show that they can be shocked by big, unexpected sounds, although they tend to adapt to constant sounds in the environment. A few indicate that babies prefer quiet, harmonious music. Loud music may produce strong kicks of protest. An earthquake sound in Italy left a group of unborn babies in a hyperactive state for several hours.
Lullabies are always appropriate.
Around the third week after conception, a folding maneuver creates the neural tube from which the brain and spinal cord develop. If all goes well, a rapid, richly choreographed set of movements will put all the basic parts of the brain in place by eight weeks. These will not be replaced. From this foundation, brain parts will send out branches and establish billions of connections necessary for the perfect coordination of the entire nervous system. This process will continue for years after birth.