The multidisciplinary study of how people change and how they remain the same over time is anthropology at it's core.
In order to really understand how people and cultures are different you must delve deeply into every aspects of their lives. Psychology, sociology, economics and especially archeology are just some of the disciplines needed to undertake the study of a society and how and why it changes. Biology is another facet to the study of people. Evolution of physical beings is an important part of change and helps explain quite about about the cultural transformations that take place over time. Similarly, the static nature of some psychological and physiological attributes are an important feature of discovering what drives us and why we are the way we are. Why, for example, are some of our most basic reactions to external stimuli called a reaction of our 'Lizard Brains'.
Anthropology tries to answer the questions where were we? what are we? and where are we going?