Cognitive Skills: Conservation

Some of the most obvious changes in children age 5 to 13 take place in the intellectual domain. Reading and writing skills improve enormously, and children's language becomes more complex, subtie, and rich, In Piaget's theory, children pass from the preoperational to the concrete operational stage at about the time they move into the second grade. As we mentioned in our earlier discussion of conceptual growth the acid test of whether children have reached the concrete operational stage is whether they can perform the mental operations that are necessary for conservation (Elkind, 1961; Flavell, 1965). This is the knowledge that quantities and other permanent characteristics of objects remain the same despite such superficial transformations as apparent shape, brightness, or size. To rake an earlier example, when water is poured from a shoe wide glass into a tall narrow one, preoperational children will say that there is now more water in the taller glass. Concrete operational children will be able to judge that the amount of water has not changed. They can do this by using three basic mental operations. The first of these is condensation.

For example, the child says that the water is the same because even though it is higher it is also narrower-one perceptual quality is compensated for by another. A second important operation is identity-the material itself, the water, is the same in the two conditions so that identity must extend to amount. The third operation is reversibility-what would happen if the water were to be poured back into the short wide container? Children who can carry out these operations mentally are more likely to judge that the amount of water has not changed.

Is the child in the concrete operational stage qualitatively different from the preoperational child? That is, do children in these two stages think in fundamentally different ways? According to Piagetian theory, yes. The older child is capable of certain mental operations that the younger child simply cannot do. If Piaget's theory is absolutely correct, it should be impossible to teach a preoperational child to conserve. Rochel Gelman (1969) tested this notion by taking a group of children who had failed the standard tests of conservation and training them to pay attention to the relevant dimensions   of situations. For example for the water problem children would be taught to look at and compare both the blight and the width of containers.

This training produced dramatic results: The children performed just like older children on tests of conservation, whereas their matched agemates   without training performed like preoperational children. Of course, it could veer well be that these children were on the verge of learning to conserve on their own and that the training simply accelerated their normal   growth patterns, To some extent, this must be true-we would hardly expect this kind of training to be effective for 1- or even 2-year-old children. On the other hand. in many situations adults would be revealed as nonconservers as well. Consider how successful creative packagers have been in making us believe chat the things we buy are more than they actually are.