The most critical part of operations is realising ‘reversibility’ = both physical and mental processes can be reversed and cancelled out by others. The concrete operational child will overcome the aspects of rigidity apparent in a preoperational child. These are: lack of reversibility.

What are the limitations of preoperational thought?

These include the inability to decenter, conserve, understand seriation (the inability to understand that objects can be organized into a logical series or order) and to carry out inclusion tasks. Children in the preoperational stage are able to focus on only one aspect or dimension of problems (i.e. centration).

Is developmental change reversible?

The prevalent view of developmental phenotypic switching holds that phenotype modifications occurring during critical windows of development are “irreversible” – that is, once produced by environmental perturbation, the consequent juvenile and/or adult phenotypes are indelibly modified.