The stages were named after psychologist and developmental biologist Jean Piaget, who recorded and studied the intellectual development and abilities of infants, children, and teens.

In it, he delineates four stages in which intelligence grows, from birth through adolescence, also known as Piaget’s Four Stages of Cognitive Development: The Sensorimotor Stage: Birth to 2 ...

Piaget's stages of development is a theory about how children learn and gain skills as they grow up, from birth to adulthood. Learn more.

Developmental psychology is also known as human development or lifespan psychology. In each of the life stages of developmental psychology, people generally meet certain physical, emotional, and ...

The Erikson stages of development are one way to look at how your child develops from birth through adulthood. Here's what you need to know about each stage.