1896 - 1980
Jean Piaget was a psychologist that started studying cognitive psychology in the 1920s. One of his greatest achievements was that he discovered that children are just as competent as adults but they think in very different ways. During his experiments, her discovered four stages of development. These stages are called Schema. Jean was surprised by the strong positive support he got from the public about his findings. He was important to psychology because before his studies, everyone thought that children were not as competent as adults.