Discuss the significance of developmental psychology to the teacher.

Developmental psychology is of prime importance to teachers.  Our knowledge of the developmental stages of our students enables us to tailor our curricula, our lessons, our teaching strategies, our assessments, and our expectations to the stages our students are in. People develop along different dimensions, cognitive, social, physical, and I like to add moral, so at any given moment, students may be highly developed in one dimension and not particularly developed in another.  All of this must be taken into consideration by a teacher. Let me give you a few examples concerning cognitive development.

Jean Piaget was a theorist who offered a theory of cognitive development that is of great use to teachers. He posited that there were several stages children go through, and until they are at a particular stage of development, they are incapable of learning certain concepts. The most striking example of this for me is pouring water from a container of one shape and size to a container of another shape and size. Until a child has reached the concrete operational stage, the child will report that the second container holds a different quantity than the first. For a teacher to try to teach a child that there is a constancy in quantity is an impossibility until the child reaches that stage.  This theory has great utility, particularly for the elementary to middle-school teacher. 

Vygotsky had a concept he called the zone of proximal development (ZPG). This concept is equally useful to the teacher in planning and expectations.  The idea is that children's development always rests on what went before, such that if there are inadequate underpinnings of knowledge or experience, a new idea or experience cannot "stick." It has nothing to stick to! When we plan our teaching, we therefore do something called "scaffolding," to be sure that what we are presenting builds on knowledge and experience that is already there. Picture trying to build a third floor on a house if you have not built the first and second already.  Vygotsky's idea is that learning is like that, too, and that as students develop, we want to build on to what is present and push ahead just a little bit at a time developmentally. 

These are two of the developmental theory greats in education, but there are others as well, and no teacher should enter the classroom without some grounding in these important theories of development.