Baby's Brain in Week 3
Even as early as his 17th week in utero, your baby's senses have been at work. And in the three weeks he's been hanging around outside your body, he's been developing one sense particularly well: Touch. Amazingly, your newborn is so sensitive to touch right now that he can distinguish the feel of one object from another.
If you put your finger inside your newborn's palm, he'll grasp it. This is the palmar reflex at work: This automatic response—which has been around since your child's first moments outside the womb—enables babies to learn about their world through touch way before their minds and fingers can work together to deliberately pick up an object all on their own for further inspection and understanding.
The palmar reflex serves young babies well as they grasp and feel various objects set in their palms. However, it fades by the six-month mark, when babies are able to intentionally pick up objects and feel them not only with their hands but also with their mouths, adding taste to his sensory-learning repertoire.
What the Research Shows
Researchers tested babies' sensitivity to touch by placing a small prism-shaped object in a series of newborns' palms, being careful to keep the babies from seeing the prism. After a while, each baby in the study dropped the prism; again and again, the research staff would replace the prism in the child's palm. The researchers noticed that with each subsequent replacement, the amount of time the babies grasped the prism decreased, as if they were already familiar with the feel of this object.
Then the researchers placed a different object—a cylinder—into the children's palms. Interestingly, the babies held this new object as long as they had the prism when it had first been placed in their hands. This indicated to the researchers that the babies recognized the object as being new and different: The cylinder had an unfamiliar feeling, and they wanted to spend more time holding it to get to know it better.