Jean Piaget's theory of cognitive development suggests that children grow and move through four different stages of intellectual development. Four stages of Piaget's cognitive development theory:Sensory-motor stage ( Birth to 2 years)Pr-operational stage ( 2 years to 7 years)Concrete operational stage (7 years) to 11 years)Formal operational stage ( 11 years +) According to Jean Piaget's theory, the reason for the above-mentioned phenomenon is that the child is yet to master hierarchical classification. It is the process of organizing things in groups by comparing on the basis of similarities and differences.Preoperational children cannot organize objects on the basis of classes and subclasses by differentiating them on the basis of their similarities and differences. They fail the class inclusion problem of Piaget.For example, If children are shown 12 pencils, 4 of which are red and 8 are yellow and when asked œif there are more yellow pencils or more pencils? they respond œmore yellow pencils completely failing to realize that both yellow and red pencils are under the category of pencils. Hence, it is clear that according to Jean Piaget's theory, the reason for the above-mentioned phenomenon is that the child is yet to master hierarchical classification. Additional InformationSeriation: It is the ability to order items along a particular dimension such as length or weight. For instance, arranging pencils from shortest to longestTransitive inference: It is the process of finding unknown relationships between objects by using multiple previous information. If stick A is longer than stick B and stick B is longer than stick C, children can draw the mental inference that stick A is longer than stick C.We think either in words or mental images. The thought we œhear in our mind in the form of statements or words is known as propositional thought.