Jean Piaget 

1896-1980  

Piaget Theories

4 min

Adolescent Cognition

4 min

Erik Erikson 

1902-1994

Eight Stages

4 min

 Lev Vygotsky

1896-1934

Zone of Proximal Development "play"

3 min 

Vygotsky

4 min 

 Lawrence Kohlberg

1927-1987

Kohlberg's moral test