Before proceeding to theory development, there are two additional theoretical areas that I would like to address. I hesitate to call them minor or peripheral theories because they both deal with the environment, a central element of transaction. Ecological anthropology and ecological psychology are two social sciences that have focused on the role the environment plays in human societies. Ecological anthropology examines and theorizes on what impact the natural environment has on the formation, transmission and modification of culture. Ecological psychology studies the role of all three elements of the environment in social behaviour and practice.