According to Piaget, there are 4 stages of cognitive development, these include: The sensorimotor stage, the pre operational stage, the concrete operational stage, and the formal operational stage. The most important element of the first stage is object permanence, which is the understanding that objects continue to exist even when they are not in view. The second stage is where children begin to struggle with logic, but learn to take the point of view of others. The third, children begin to use logic and become less egocentric. The fourth stage is where children form the ability to use deductive reasoning, and begin to understand abstract ideas.