Final answer:
Piaget termed the cognitive development stage from ages 2 to 6 as 'preoperational intelligence' because children of this age do not use logical operations, such as understanding quantity conservation, affecting their perception of amount as seen in beliefs about divided pizza slices.
Step-by-step explanation:
Jean Piaget called the stage of human cognitive development between the ages of 2 and 6 "preoperational intelligence" because children at this stage do not yet use logical operations. Children in the preoperational stage can engage in pretend play and use symbols to represent objects, but they lack the ability to perform mental operations such as understanding conservation. For instance, young children may not grasp that the quantity remains the same when the appearance of an object is altered, leading to misconceptions about amounts or volume. This limitation is exemplified when a child thinks they have more pizza simply because it is cut into more pieces.
However, as children exit the preoperational stage and enter the concrete operational stage (around 7 to 11 years old), they begin to think more logically and understand the concept of conservation. By this point, they can perform mathematical operations and understand that changes in shape or appearance do not necessarily mean changes in quantity. Cognitive skills continue to develop into middle childhood, leading eventually to the abilities described in Piaget's formal operational stage, where abstract and hypothetical thinking become possible.