Little children are superb learners

Little children are superb learners because their brain is still in the process of development.

Their span of attention may be short but since the prefrontal cortex of their brain is still in the developing stage. The prefrontal cortex of the brain is the site of working memory which in an adult is well developed as a result memories are stored and fixed in the region.

An adult will see a broom as a broom but a child can have the tendency to treat a broom as a javelin or a stick. This inventive nature of the child is due to the under-developed prefrontal cortex of the child.  

The imaginative and creative brain of the child helps him/her to think out of the box and accept changes very easily. No doubt even after using his/her mother tongue at home as a means of communication, the child starts picking up English or Hindi very fast after attending school for a few days.

The creativity of a child helps him/her to solve task more easily than an adult. A child's brain is designed to learn as opposed to an adult's that is designed to perform.

As a child grows up to an adult he/she has set notions and ideas and accordingly execute work, but as a child, he or she is ready to take challenges and this promotes learning. Therefore teaching a foreign language to a child is much easier than an adult. Their underdeveloped brain helps them to adapt to new social convention more easily than adults.  

The only drawback is that an underdeveloped brain of a child does not allow him to a behave appropriately in a situation for which portraying a role model is very important to enable the child to learn about the virtues of life and grow up into a good human being.