Jean Piaget

Jean Piaget was a Swiss psychologist most famous for his theories on cognitive development in children,. Early in his career he noticed that children think differently from adults. He theorized that children filter knowledge from their experiences and environment into groups called schemas which are cognitive frameworks that help us organize information. Piaget developed stages of cognitive development that children progress through at certain ages. There are four stages:

The Sensorimotor phase lasts from birth to 2 years of age and is when the baby's knowledge is limited to perceptions from their basic senses and motor activities.

The next phase is the Preoperational phase which lasts from age 2 to age 6. This phase is characterized by the learning of language, an absence of logical thought, and an inability to look at things from another person's perspective.

The Concrete Operational phase starts around age 7 and lasts until age 11. This is when children begin to use logic in their thinking but they still have difficulty with abstract ideas.

The final phase is the Formal Operational phase which begins at age 12 and lasts until adulthood. This is when children develop the ability to think about abstract concepts. This is usually when students begin to take algebra and other types of concepts that use abstract ideas. Piaget's theories are still used in developmental psychology research in the present day.