A child who concentrates does not disturb others.The teacher must recognize the first moment of concentration and must not disturb it. The whole future comes from this moment and so the teacher must be ready for non-interference when it occurs.
This is very difficult because the teacher has to interfere at every moment before the children are normalized. Generally teachers interfere when a child is working. They go to see what they are doing and praise them. This praise is an interference. The teacher goes to correct mistakes; this is an interference, even though it is an interference of good will.
It is not interference to interfere when the child is naughty but this is just when Grown-ups often say, “Oh the child is so full of life”, whereas when the child is working seriously they will often go and say “What are you doing? Show me”. Then the concentration is broken; it finished. So never interfere when a child is working by himself.
Don’t be preoccupied about whether he is making mistakes, you must not correct him at this moment. The important thing is not that the child should handle the material, but that this material has attracted the attention of the child.
The child corrects himself through repeating the exercise, through the control of error which is exact for some of the material. If you interfere, a child’s interest finishes, the enchantment of correcting himself is broken. It is as though he says “I was with myself inside.You called me and so it is finished. Now this material has no more importance for me”. A child does not need praise; praise breaks the enchantment. It is a great inner energy, normality, which comes, and you break this if you interfere.
— Maria Montessori from “The Child, Society and the World” (Page 15)