Brain Hemisphere Coordination in Kid's Piano
Brain hemisphere coordination is a key factor in how well kids handle the motor skills necessary to play the piano. At the piano, regardless of whether a child is left or right handed, they are properly taught to make the right hand the dominant one. In addition, they will learn to be ambidextrous regardless of which hand started out as the "dominant" one.
Before you expect anything of a child, see what state their brain hemispheres are in. Specifically, can the two hands do different things?
Head Pat, Stomach Circle
Remember the child's game where you pat your head with one hand, and circle your stomach with the other? That silly game is a perfect diagnostic tool for the stage of development of children's brain hemispheres. If they have difficulty with that game, it's a fair bet that their hemispheres are only starting to coordinate. Don't rush or you'll frustrate them. Remember, the hemispheres can be trained to talk to each other. In fact, that's largely what piano lessons really are.
A realistic approach is to defer to the comfort of the child to a certain degree. Refrain initially from two-handed experimentation until they grow more. But this approach must be blended with repeated, gentle attempts to use two hands. If the child never tries it there is less chance of them getting the knack of it.
A Simple First Step
There are pieces in which the two hands do not play at the same time, and this is always a good first step. The very first step towards two-handed playing with preschoolers and the very young is to get them to use two index fingers instead of one.
Just banging away the piano with two index fingers gets their brain the antiphonal (side to side) exercise it needs. This simple ruse of two index fingers forces the child to use both sides of the brain without discomfort, since within each hand one finger is dominant to a child, and it is always the index finger.
First Awareness Of Fingers
It is the use of the other fingers that baffles kids at first. Their brains haven't yet straightened out what their fingers are really doing there at the end of their hands. Piano is the first place they are asked to be aware of it. So the best course is to confine yourself to the strongest fingers if you want to start learning with both hands. The thumb is useful to a child in a subconscious way for everyday tasks, in the sense of the opposable thumb and forefinger.
The Thumb Is Strange To Kids
But conversely, the thumb is difficult for a child to incorporate into their "piano hand scheme." It is the shortest finger. Plus, the index finger is dominant and its dominance is difficult but necessary to replace with that of the thumb.
Careful observation of children's motor skills leads a piano teacher to make better choices of action with young students. The source of almost all discomfort for children at the piano is the teacher's disregard for their brain hemisphere development.