Piaget believes that people are born with an innate ability to organize their thinking processes. As people mature, their thinking processes go through stages of development. Anita Woolfolk in her book “Educational Psychology” states that people pass through the same stages in the same order. These stages are not intended be used to label individuals; they are only guidelines. Some people may go through periods of transition between stages. The first stage of development is called the sensorimotor stage during which babies understand that objects exist. The ability to use symbols emerges during the second stage, and is called preoperational stage. Next, follows the concrete operational stage, when children can think logically. Finally, during the formal operational stage, deductive reasoning emerges.
According to the Vygotsky model, surrounding culture determines what an individual will learn. The zone of proximal development is a point where a child has mastered certain skills and can perform these tasks without assistance, but requires the help of an adult to get to the next level of mastery. It is at this point, that instruction is most successful. There is no age range or limit. Unlike Piaget, Vygotsky does not describe how children think. ZPD simply refers to the moment that a person has acquired a skill and is ready to be introduced to the next skill. The main mechanism for learning is private speech.
Both Piaget’s and Vygotsky’s learning models feature the role of private speech. Private speech is self-talk that guides thinking and action. Vygotsky placed more emphasis on language than Piaget because he believed that thinking depends on language. Private speech is a form of self-regulation that allows a person to plan, monitor and guide his thinking. As children get older, they stop speaking their thoughts aloud, and their self-talk becomes internalized. Piaget called children’s self-directed speech “egocentric speech” because he believed a child’s ability to see something from another person’s perspective was very limited. The most immature children use the most self-talk. As children mature, they develop socialized speech, in which they speak to communicate with others.
According to Woolfolk, many psychologists do not agree that there are four separate stages, but they do agree with how Piaget describes changes in learning. The learning process may be more continuous. Another criticism is that Piaget's model underestimates children's abilities. Vygotsky's ideas are very general and do not include a detailed theory of how an individual's thinking develops. No clear applications for the classroom are available. There is much emphasis on culture and little attention to a person's biological predisposition.