 Socio-cultural evolution Socio-cultural evolution is a more cultural evolution art theories of cultural and social evolution that describe how cultures and societies change over time. Whereas Socio-cultural development traces processes that tend to increase the complexity of a society or culture, Socio-cultural evolution also considers process that can lead to decreases in complexity degeneration or that can produce variation or proliferation without any seemingly significant changes in complexity clad of genocides. Socio-cultural evolution is the process by which structural reorganization is affected through time, eventually producing a form or structure which is qualitatively different from the ancestral form. Most 19th century and some 20th century approaches to Socio-culture aimed to provide model for the evolution of humankind as a whole, arguing that different societies have reached different stages of social development. The most comprehensive attempt to develop the general theory of social evolution centering on the development of Socio-cultural systems, the work of Talcott Parsons 1902-1979 operated on a scale which included the theory of world history. Another attempt, on a less systematic scale, originated with the world systems approached from the 1970s. More recent approaches focus on changes specific to individual societies and reject the idea that cultures differ primarily according to how far each one is on some linear scale of social progress. Most modern archaeologists and cultural anthropologists work within the frameworks of neo-evolutionism, socio-biologists, and modernization theory. Many different societies have existed in the course of human history, with estimates as high as a total of over one million separate societies. However, as of 2013, the number of current, distinct societies had been estimated as only about 200.