Human development involves studies of the human condition with its core being the capability approach. The inequality adjusted Human Development Index is used as a way of measuring actual progress in human development by the United Nations. It is an alternative approach to a single focus on economic growth, and focused more on social justice, as a way of understanding progress The United Nations Development Programme defines human development as "the process of enlarging people's choices", said choices allowing them to "lead a long and healthy life, to be educated, to enjoy a decent standard of living", as well as "political freedom, other guaranteed human rights and various ingredients of self-respect". Thus, human development is about much more than economic growth, which is only a means of enlarging people's choices. Fundamental to enlarging these choices is building human capabilities—the range of things that people can do or be in life. Capabilities are "the substantive freedoms [a person] enjoys to lead the kind of life [they have] reason to value". History Human Development Theory has roots in ancient philosophy and early economic theory. Aristotle noted that "Wealth is evidently not the good we are seeking, for it is merely useful for something else", and Adam Smith and Karl Marx were concerned with human capabilities. The theory grew in importance in the 1980s with the work of Amartya Sen and his Human Capabilities perspective, which played a role in his receiving the 1998 Nobel Prize in Economics. Notable early active economists who formulated the modern concept of human development theory were Mahbub ul Haq, Üner Kirdar, and Amartya Sen. The Human Development Index developed for the United Nations Development Programme (UNDP) stems from this early research. In 2000, Sen and Sudhir Anand published a notable development of the theory to address issues in sustainability. Martha Nussbaum's publications in the late 1990s and 2000s pushed theorists to pay more attention to the human in the theory, and particularly to human emotion. A separate approach stems in part from needs theories of psychology which in part started with Abraham Maslow (1968). Representative of these are the Human-Scale Development approach developed by Manfred Max-Neef in the mid-to-late 1980s which addresses human needs and satisfiers which are more or less static across time and context. Anthropologists and sociologists have also challenged perspectives on Human Development Theory that stem from neoclassical economics. Examples of scholars include, Diane