In 20th century there evolved Neo –Evolutionism with Leslie White,Julian Steward,Marshall Sahlins and Elman Service as main propounders.
Leslie White emphasized that the evolutionary stages are abstractions applicable to the growth of human culture. He also believed that culture is to be studied in its own terms. He suggested the term culturology to the science of culture. He is known to be the proponent of General Evolution where he says that it has been studied entirely on a culturological level. According to him culture grows out of culture with new combinations, syntheses continually formed. He also says that technology is the basic determinant of cultural evolutionism. He also refers to it as Cultural Materialism. According to him, the other factors remaining constant, culture evolves as energy harnessed per capita,per year is increased, the system not only increase in size but become more highly evolved , they become more differentiated and more specialized functionally.
Julian Steward says that Cultural Evolution may be defined as quest for regularities or laws. There are three ways in which evolutionary data can be analysed
Unilineal evolution: the classical 19th century formulation which dealt with particular cultures, placing them in stages of universal sequence.
Universal evolution: This designates the modern revamping of unilineal evolution which is concerned with culture than with cultures.
Multilinear evolution: It is distinctive in searching parallels of limited occurrence instead of universals. He doesn't believe that culture followed a single line of development. His generalizations are based on intensive study of particular cultures. For him, multilinear evolution is a methodology based on the assumption that regularities in culture change occur. This is concerned with historical reconstruction with any set laws.
Marshall Sahlins and Elman Service have combined the White and Steward's views by recognizing two kinds of evolution.
Specific Evolution refers to the particular sequence of change and adaptation of a particular society in a given environment.
General Evolution refers to general progress of human society in which higher forms arise and surpass lower forms.