Jean Piaget made a systematic study of cognitive development among children of different age groups and he categorized it into different developmental stages. He is also known as the father of child Psychology. According to him, development is based on the physical environment or Biological abilities, he ignores social aspects.According to him stages of the cognitive development are-Sensory-motor:(birth to 2 years) Preoperational: (from age 2 years to 7 years)Concrete operational:(from 7 years to 11 years) Formal operational: (from11+ - adolescence and adulthood). Sensory-motor stage: In this stage of birth to two years, the changes are seen in a child as Reflex actions, Intimate behavior, Schema formation, and senses are the teacher at this stage.Schema: Schema is an already existing mental set up in the mind which is a pattern of repeated behavior that allows children to explore and express developing ideas and thoughts through their play and exploration where the senses are the only teachers of children.Schemas are the building blocks of thinking that allow children (everyone) to mentally represent the objects and events in our world.Human babies are born with these schemas and tried to relate their schemas to real-world situations.Important PointsZone of proximal development: ZPD is the difference between the present level of development attained without anyones assistance and the potential level of development that can be attained under the guidance of MKO (more knowledgeable others).Advance organizer: Advance organizer works as a tool, in which a teacher presents the topics, ways, and structure in which they will learn.Reflexes: Reflexes are the actions performed by the child, such as sucking, looking, grasping, etc.Additional Information StagesChan?gesSensory-motor stage Senses are teachersSchema formationReflex actionsIntimate BehaviorPre-operational stage Language developmentIrreversibilityEgocentrismAnimismConcrete operational stageLogic beginsReversibilityClassificationConservationFormal Operational stageHypothetical-deductive thinkingDivergent/Convergent thinking.Creative Thinking.