Answer:
The formal operational stage
Step-by-step explanation:
Jean Piaget, a developmental psychologist is known for developing the Piaget’s theory of cognitive development. This theory sees cognitive development in an individual as a gradual process that begins from birth, and continues as the child grows up. Piaget describes this process of cognitive development into 4 stages, which are the sensorimotor, preoperational, concrete, and formal operational.
The formal operational stage, which Piaget’s describes as the stage that begins as from 12 years upward, is characterized by a remarkable development of the child’s ability to engage in abstract reasoning and logic. The individual is able to form moral and philosophical thought as his abity to engage in abstract reasoning increases.