The fetal brain can discriminate environmental events and can learn and retain information about environmental stimuli. The heart rate of the fetus changes when sounds occur in the environment. (LeDoux, Joseph. Synaptic Self. p 92. NY:Penguin Books, 2002.)

Auditory centers in the brain stem emerge. (Schwartz, Jeffrey M., MD, and Sharon Begley. The Mind & the Brain. p 124-125. NY: Regan Books, 2002.)