Gradually he pieced together a "blueprint" for normal cognitive development in children, and presented ... Piaget found four major developmental stages (with many subdivisions).

Every child is developing within a context and however normal our own culture feels to us, there is no objective context-free norm that we can compare other children to. That is, to say, we should ...

Medically reviewed by Jonathan B. Jassey, DO Tanner stages are a tool used by healthcare providers to evaluate development in puberty. They detail five specific stages of physical change in puberty, ...