Brain, paradigms and exposure to the environment

Soon after birth, babies are put into the arms of their moms, they start seeing things, noticing people and objects around them. 

That crowns their incipient interaction with their environment.
Unlike most animals, we don't come hard-wired with all the skills that we need in life, we acquire them through experience and exposure, from sticking our hands into fire and recoiling in pain, to eating inedible substances and choking in disgust.
We come with a "crude", basic mind and our wiring is performed as a result of our contact and cooperation with our immediate surroundings.
The neural pathways that we often use get strengthened, while the unused brain connections get weaker.
This process allows us to become expert in certain fields to the detriment of others.
In some case, infants don't get the exposure they need to be able develop some essential life skills. 

Over-sheltered kids for example,  have a limited access to challenging situations outside of their houses. 

The wiring dealing with the complexities of real life situations will be weaker, on the other hand they might have an over-developed wiring when it comes to reading and writing, if they spend time immersed in these activities.

Once we stop an activity for an extended period of time, the neural pathways dedicated to it get either pruned or dedicated to other activities that might be in need of extra resources.