Piaget was best known for his work in cognitive development. He was also known best for his work with children and discovering the developmental stages of childhood up through twelve years old. These stages are sensorimotor, pre-operational, concrete operation, and formal operational. He has helped those in the educational field understand why students act the way they do and what type of material is appropriate for their age level. For example, it is not feasible to teach five and six year olds how to think abstractly because their brains have not developed the ability to think abstractly yet. "Piaget felt that the difference between humans and animals was the fact that humans are able to do reasoning through abstract symbolism." He was interested in how thought processes with younger children differed from older children and why their reasoning skills were different.
Vygostsky is also one that was important in developing theories that are used in the education system. He developed the theory of social development as well as the zone of proximal development. The zone of proximal development is the idea that there are some ideas and theories that are too difficult for children to master on their own but can be mastered with help and guidance.