Although children can learn a great deal on their own, conversations with parents have a big influence on the content, recall and transfer of what they learn.
Like parent, like child. Children become who they are with the influence of all of their past experiences and often, the parents are a large part of that influence.
There are many reasons to study the development of hand preference in infants. For one thing, being left-handed can be an advantage in one-on-one sports such as tennis.