What is the importance of psychology to a preschool teacher?

Nobody would suggest that one needs to be a specialist in psychology to be a preschool teacher, but some background in psychology, especially developmental psychology, would be helpful. This is because so much of pedagogy (the study of teaching and learning) is based upon developmental psychology. In short, it is important to understand how children's minds develop, emotionally, cognitively, and behaviorally, so that we can tailor instruction to meet their needs. This is important at every level of education from pre-K to post-secondary, but it is perhaps most important at the preschool level, where kids are becoming socialized and beginning to gain basic educational skills such as reading and speech that are crucial to their future development. In fact, a basic familiarity with developmental psychology is useful not just for early childhood teachers, but for coaches, babysitters, and parents as well. I have linked to a scholarly article that deals with this very subject and provides an overview of recent scholarly work on developmental psychology and pedagogy.