Concrete Operational Stage. This period begins from approximately age seven and stops eleven years of age, rational thought develop with the child emphasising categorization by similarity and difference. Logic is usually only useful to things that are physical or can be seen. This is why many children’s maths books now have counters or number lines at the top of the page to assist the concrete thinker. An additional goal that is achieved at the conclusion of this phase is reversibility, which is essential to enable the child to have a conservation. Reversibility is the capability to psychologically undo an action. Decentring takes place during this period. The child becomes less self-centred in their thinking and able to take the viewpoint
