Conservation, according to Jean Piaget, is attained when a child is able to retain in his or her memory the characteristics of an object that has been changed aesthetically. A child who can perceive unchanged or invariant properties of an object after it has undergone physical transformation is able to reverse the transformation mentally and understands conservation. According to Piaget, conservation occurs at any moment in the life of a child between 7-11 years of age, when the child has acquired the ability to use logic in his or her reasoning.
Piaget believed reality to be a dynamic system where things, as well as people are experiencing constant transformations and states. For example, people undergo physical changes as they grow older, and plants may grow taller from one season to another. States represent the conditions or forms that people or things can take during a certain stage between transformations. For example, a man may acquire a mustache when he is a teenager rather than when he’s a child. Leaves from trees usually fall in autumn, not in winter.
One of Piaget´s most famous conservation tests involves showing a child two identical glasses, both of which contain the same quantity of liquid. The child is asked whether the two glasses contain the same quantity of liquid. Then the liquid from one glass is poured into a taller, thinner glass. The child is asked again if whether both glasses contain the same amount of liquid. A child who is not able to distinguish conservation will answer that there is more liquid in the tall, thin glass. Piaget concluded that confusion could stem from the child´s inability to comprehend the notion of reversibility, which usually occurs during the preoperational stage.
Through a series of stages (cognitive development), Jean Piaget describes the way in which human traits are acquired. From birth to about 2 years of age, infants are not capable of perceiving the world out from their immediate surroundings, and their behaviors are limited to motor responses of sensory stimuli. From 2-7 years, children have learned to represent unseen objects; however, they have not developed the ability to use deductive reasoning. In the following stage, which occurs anywhere between 7-11 years of age, a child has developed the ability to think logically, and can operate many important cognitive processes, among which is found the one referring to conservation.
According to Jean Piaget, a child´s ability to understand conservation occurs at any time between 7-11 years old, during the concrete operations stage of a child’s development which he describes on his theory of cognitive development. The theory deals with the nature of knowledge and the way in which humans gradually acquire it. According to Piaget, reality involves transformations and states, and human intelligence develops the ability to adapt to these transformations. To do so, it must develop certain functions that enable the representation of both the transformational and static aspects of reality.
During the concrete operational stage, a child has acquired the ability to use logic in his or her reasoning. For example, if given objects of different sizes, a child may be able arrange them in order according to size; if given a number of pencil colors, a child may be able to combine them to obtain another color. A child understands that a balloon can be inflated and deflated over and over again for the purpose of play. It is during this stage that a child understands that a given quantity will remain the same despite transformations of size and shape, thus, a child has developed the ability to recognize conservation.
Despite the influence of Piaget´s theories on psychology and education, recent research has resulted in criticism of some of Piaget’s theories, including how students understand conservation. Piaget observed that conservation occurred at the same range of age in a child’s development; however, recent studies have shown that a child can learn certain concepts before he or she has reached stages of Piaget's development. Moreover, studies suggest that children may acquire many of the abilities suggested by Piaget at an earlier age. Despite criticism, Piaget’s work may be better appreciated for its contributions to developmental psychology and education.