What is a key characteristic of the formal operational stage of development?

The formal operational stage of development, as outlined by Jean Piaget, is characterized primarily by the capacity for abstract thought. This stage typically begins around the age of 12 and represents a significant leap in cognitive capabilities. During this stage, individuals can engage in theoretical reasoning, think about hypothetical situations, and consider abstract concepts that are not immediately present or concrete. This ability allows for philosophical thinking, problem-solving, and the formulation of hypotheses.

In contrast, the other characteristics listed correspond to earlier stages of cognitive development according to Piaget's theory. Understanding conservation of mass, for instance, occurs during the concrete operational stage, where children grasp the concept that quantity remains the same despite changes in shape or appearance. Object permanence, the understanding that objects continue to exist even when they cannot be seen, is developed during the sensorimotor stage of infancy. Lastly, language acquisition typically emerges during early childhood and is not specifically tied to the formal operational stage. Each of these abilities reflects cognitive skills developed before reaching the capacity for formal operational thinking.