A child is enjoying piling zigsaw puzzle up in a heap. It keeps sliding and collapsing, so the child is placing pieces with increasing concentration.
A parent interjects “that’s not how you play with puzzles.”
A child is playing house with an aunt. They are giggling and having a great time. A parent interrupts “Addi, tell Aunty what happened at school today!”
You get the point.
If a child is concentration on something, and it’s doing no harm to anyone, leave the child alone.
I’m not a doctor of any kind, and I’m not saying this heals attention deficit disorders or ADHD anything. I’m just saying a child without a disorder would develop concentration by practice. Next time, observe siblings. I would bet that the middle child – or whichever one that gets less attention – has the best and longest concentration.