Chapter 2 describes several important developmental theories and how these theories help us make sense out of tremendous amounts of information about our experiences and understanding of development. Each of the grand theories (psychoanalytic cognitive and behavioral) provides important insights on development each with a different focus on emotions thinking and behavior. Web Links for Ch. 2 provide additional information about Freud Vygotsky Piaget and Erikson and their theories. Video lesson 1 The developing Person explores the major theories of development and points out that development is a lifelong process.