In Piaget’s theory, a stage of cognitive development occurring roughly between the ages of seven and eleven, is the stage of concrete operations. According to Piaget, a child’s mastery of conservation marks the beginning of this stage. Logical thought emerges in this stage.
The key developments at this stage are as follows :
Conservation : Children at this stage under-stand that physical entities (weight, length, amounts) remain fixed so long as nothing is added or taken away from it, though it might appear different. Understanding of this nature’s constant is known as conservation.
The various kinds of conservation are :
Conservation of substance: Two identical clay balls are presented. The subject admits that they have equal amounts of clay. If one ball is deformed into the shape of a “sausage”, the subject will still say that both contains equal amounts of clay at this stage.
Conservation of length : Two sticks are aligned in front of the subject and he admits their equality. Now if one of the sticks is moved to the right, and the subject is asked whether they are of the same length, the subject will admit that they are still of the same length.
Conservation of members : Two rows of clay balls are placed in one-to-one correspondence subject admits that both rows have equal number of balls. Now, one of the rows is elongated or contracted and subject is asked whether both the rows still have the same number of balls. They admit equality.
Conservation of liquids : Two beakers are filled to the same level with water. The subject sees that they are equal. Now, liquid of one container is poured into a tall tube. The subject is asked whether each contains the same amount. At this stage, They agree that each contains the same amount.
Conservation of area : In two identical cardboard’s same number of identical wooden blocks are placed in identical portions. Then the subject is asked whether each cardboard has the same amount of space remaining. The experimenter then scatters the blocks on one of the cardboard’s. The subject is asked the same question. In both the cases, the subject admits that same amount of space is left.
Reversibility : In this stage, children can solve the questions mentally. They do not need to measure or weigh objects.
For example —
In the famous Muller-Lyer illusion : In the figure, in step
1, a child agrees that stick A and stick B are equal. In step
2, stick B appears longer than stick A. But children in the concrete stage are capable of mentally reversing the arrows shafts to its original configuration, would admit it to be the same as stick A.
Categorization : This includes abilities such as ‘seriation’, ‘transitive inference’ and ‘class inclusion’.
• Seriation : It refers to the ability to arrange items along a dimension such as weight (lightest to heaviest) or colour (lightest to darkest).
• Transitive inference : It refers to the ability to recognize a relationship between two objects by knowing the relationship between each of them and a third object.
For example : Amenda is shown three sticks — a yellow, red and green. She has been told that the yellow stick is longer than red one and the red one is longer than the green one, then without physically comparing the yellow with the green one, she can tell that the yellow stick is longer than the green one.
Class inclusion : Class inclusion is the ability to see the relationship between the whole and its parts. For example—A bunch of ten flowers (seven roses and three carnations) is shown to the children at this stage and asked whether there are more roses or more flowers. They realize that roses are a sub-class of flowers and therefore there cannot be more roses than flowers.
Spatial thinking : Children at this stage can understand spatial relationship, i.e., they have a clear idea how far it is from one place to another and how long it takes to get there. They have the ability to use maps and models.
Inductive and deductive reasoning : Children at this stage use inductive reasoning, rather than deductive reasoning. It refers to that type of logical reasoning that moves from particular observation about members of a class to a general conclusion about the class.
For example : My dog barks, so does Jerry’s dog and Melissa’s dog. So, it looks as if all dog’s barks.
The children at this stage, however, cannot very clearly think of hypothetical propositions. Also, they cannot understand the broad meaning of abstract concepts such as freedom, integrity. Intellectual growth, is still incomplete.