 The stages are the sensorimotor stage from birth to 2 years old, the preoperational state from 2 years old to 7 years old, the concrete operational stage from 7 years old to 10 years old, and formal operational stage from 12 years old and up.He also believed that learning was constrained to the child's cognitive development.Piaget influenced educational psychology because he was the first to believe that cognitive development was important and something that should be paid attention to in education.