​According to Jean Piaget ...

During Middle Childhood, we see the emergence of what Piaget named the Concrete-Operational Stage. You might ask what does Concrete Operations mean? Concrete-Operations refers to the time where children are beginning to develop the capacity for adult logic. This generally lasts through to around age 12. The thinking during this stage is generally characterized by reversibility, flexibility and decentration. The concrete operational child is able to look multiple parts of a problem at once. There are 3 main areas which show that a child is using this stage. They are Conservation, Transivity, and Class Inclusion Conservation: This refers to the ability to look at two objects with different properties and dimensions and still see the same thing. In the video below they show this by using two balls of clay. A preoperational child would see the two balls the same, until the second ball is flattened. The concrete-operational child is able to understand that because both balls of clay started out the same, they remain the same amount. This example holds true for the second example in the video of the liquid in the different glasses. Piaget: The Concrete-Operational Stage - Conservation


The Principle of Transitivity: "If A exceeds B in some property (say, age or height) and if B exceeds C, then A must also exceed C." (Rathus, S & Rinaldi, C., 2009)

This can be shown in a variety of ways, but the most common way is to have the child place blocks of various sizes in order. Seriation is the term used to place objects in order. Below is an example of seriation.


Class Inclusion:

this refers to the ability to see that one class of things includes several sub-classes. An example of this is given in the text book and pictured below. In the example provided the child is asked if there are more animals or dogs. The concrete-operational child would answer animals as both cats and dogs are sub-classes of animals.


Piaget's theories are widely accepted, but not without criticism. The biggest criticism is not that the stages are wrong but that the ages that correspond to the stages are incorrect. It is also believed that the stages do not happen all at the same time, rather that they emerge gradually over time. In conclusion, Piaget's theory has been challenged but has stood up to the criticism and is still taught today.