Descriptive Ethics is a value-free approach to ethics which examines ethics from the perspective of observations of actual choices made by moral agents in practice. It is the study of people's beliefs about morality, and implies the existence of, rather than explicitly prescribing, theories of value or of conduct. It is not designed to provide guidance to people in making moral decisions, nor is it designed to evaluate the reasonableness of moral norms.
It is more likely to be investigated by those working in the fields of evolutionary biology, psychology, sociology, history or anthropology, although information that comes from descriptive ethics is also used in philosophical arguments.
Descriptive Ethics is sometimes referred to as Comparative Ethics because so much activity can involve comparing ethical systems: comparing the ethics of the past to the present; comparing the ethics of one society to another; and comparing the ethics which people claim to follow with the actual rules of conduct which do describe their actions.