The answer to this question – why does this child need “special” training while the others didn’t or don’t – is that no one actually knows why this happens to siblings within the same family.
If you have more than one child, then you have probably thought this at some point or other.
You may have compared their developmental achievements, general behaviour, likes and dislikes and found great disparities.
With sets of twins, for instance, you may find that one readily accepts the behaviour modification techniques introduced by the parent or parent while the other takes much, much longer to settle in.
In situations such as this, modifying the techniques to suit each twin as opposed to imposing the chosen technique to suit them both is advised.
That there exist disparities in all living species (including same species plants and animals grown or reared together) is a known fact. This then goes to mean that for each of your children, you may need different training and teaching methods in order for you to get them where you want.
Just to throw in a bit of child developmental psychology.
Lev Vygotsky talked about a stage of development called the Zone of Proximal Development commonly known as the ZPD.
When in this zone, children need parents, for instance, to teach them what they do not know, kind of like providing them with scaffolding via supportive activities and spending time with them to help build their world better.
So instead of comparing your child’s achievements to that of his or her siblings and peers, it might be better to provide him/her with the scaffolding necessary for his/her learning.
If you are trying to teach your child new skills and are finding it challenging ask me about the very effective Triple P (Positive Parenting Program) tools that you can use.