Concrete Operations Stage - The Middle Childhood

Period of Concrete Operations (7-12 years)

Characteristic Behavior:

Evidence for organized, logical thought. There is the ability to perform multiple classification tasks, order objects in a logical sequence, and comprehend the principle of conservation. thinking becomes less transductive and less egocentric. The child is capable of concrete problem-solving.
Some reversibility now possible (quantities moved can be restored such as in arithmetic: eg. 3+4 = 7 and 7-4 = 3, etc.
Can sort unlike objects into logical groups where previously it was on superficial perceived attribute such as color. Categorical labels such as "number" or animal" now available.
Achieves conservation of number (age 6), mass (age 7), and weight (age 9)

Classifies objects according to several features and can order them in series along a single dimension such as size.
Can think logically about objects and events.