Pedro is a 4-year-old who is having lunch with his mother and sister. when his mother pours the milk that is left in the carton into the children’s glasses, she finds that there is not enough to fill both glasses; so she carefully pours half of the milk in the shorter, fatter glass in front of pedro and half into a thin, taller glass in front of pedro's sister. immediately, pedro complains that his sister got more milk than he did, and even when his mother tries to explain that they both got the same amount, pedro insists he is right. in this example, pedro is demonstrating a lack of development in the area of

conservation

Explanation:

Conservation is a factor in child development, where the child is aware of the differences in fluid quantities, objects, and other things. This factor is usually developed between the ages of 8 and 12, so it is normal for Peter, who is only 4 years old, to be deficient in the concept of "conservation" and unable to understand that the amounts of milk in his cup in your sister's cup are the same.

The preservation is inserted in the development phase called the concrete operative. This phase is marked by the beginning of concrete logical thinking, children going through this stage begin to mentally manipulate the representations of the things they internalized during the past stages. The problem is that this manipulation can only occur with concrete things arranged in the real world. Abstract concepts are not yet understandable. In this phase, the child understands that both glasses have the same amount of juice, that is, they have the notion of conservation.