Human sensory development starts in the womb and much earlier than one may think.
Touch (tactile System): Babies begin moving in the womb as early as 7 weeks and nerve endings are working by 11 weeks. Babies being exploring their environment by putting their hands together, touching their faces and mouths as well as grabbing at their umbilical cord, feet, etc. and demonstrate early tactile reflexes by 26 weeks. Any viable newborn can sense pain, pressure and temperature.
Taste (Gustatory System): Babies’ tongue buds begin developing at 4 weeks and mouth and tongue development is complete by 8 weeks and taste buds are developed by around 20 weeks. Babies at that age demonstrate being able to distinguish between sweet and bitter/sour tastes and tastes run on newborns even shows even shortly after birth babies have taste preferences.
Smell (Olfactory System): The nose is formed between 11 and 15 weeks and amniotic fluid can have as much as 120 different “smells” which the baby interacts with. It is also believed that babies are conditioned in the womb to learn certain smells which they then prefer and search for after birth (smells such as breastmilk).
Hear (Auditory System): The ear is not structurally complete until 24 weeks, but recent research has shown that babies begin reacting to sounds around 16 weeks and their reaction to sounds may be through movement, an increased heart rate, change in color, respiration and even metabolic changes.
See (Visual System): Eyes begin developing around 3 weeks and while analyzing eyesight in the womb is tricky, it is known that eyelids remain closed until 26 weeks though babies at this age are sensitive and responsive to light and twins are able to touch and grab each other by 20 weeks.
Even in the womb, babies are truly amazing and magical:
(Honeybun at about 33 weeks)
For more information on prenatal sensory development see:
https://birthpsychology.com/free-article/fetal-senses-classical-view#.U6r5B_ldXjI
http://www.infantva.org/documents/conf-prenatalsensorydevelopment.pdf
