Sociocultural evolution, sociocultural evolutionism or social evolution are theories of cultural evolution that describe how societies and culture change over time. Whereas sociocultural development traces processes that tend to increase the complexity of a society or culture, sociocultural 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 (cladogenesis). Sociocultural evolution is "the process by which structural reorganization is affected through time, eventually producing a form or structure that is qualitatively different from the ancestral form".Compare:

Evolutionary sociology and biosociology are subfields of sociology. Evolutionary sociology refers to scholarship examining the interaction between human evolved traits and predispositions with social and material environments. Biosociology refers to scholarship examining the interaction between biomarkers (genes, hormones, polygenic scores, etc.) and social and material environments. This distinction roughly follows the classical distinction between “ultimate” and “proximate” causes. Ultimate or evolutionary causation focuses on the reasons a trait evolved and its adaptive functionality, and the role of evolved traits in social behavior is the focus of evolutionary sociology.Mayr, E. (1961). Cause and effect in biology. Science, 134(3489), 1501–1506. Biosociology, by contrast, has a proximate focus, emphasizing mechanisms driving behaviors via hormonal, (epi-)genetic, neural, or other physiological pathways.Tinbergen, N. (1963). On aims and methods of Ethology. Zeitschrift für Tierpsychologie, 20, 410–433.Laland, K. N., Sterelny, K., Odling-Smee, J., Hoppitt, W., & Uller, T. (2011). Cause and effect in biology revisited: Is Mayr's proximate-ultimate dichotomy still useful? Science, 334(6062), 1512–1516.

Most of the 19th-century and some 20th-century approaches to socioculture aimed to provide models 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 a general theory of social evolution centering on the development of sociocultural systems, the work of Talcott Parsons (1902–1979), operated on a scale which included a theory of world history. Another attempt, on a less systematic scale, originated from the 1970s with the world-systems approach of Immanuel Wallerstein (1930–2019) and his followers.

More recent approaches focus on changes specific to individual societies and reject the idea that cultures differ primarily according to how far each one has moved along some presumed linear scale of social progress. Most modern archaeologists and cultural anthropologists work within the frameworks of neoevolutionism,and modernization theory, on one hand, and particularist approaches, on the other.

Introduction While the history of evolutionary thinking with regard to humans can be traced back at least to Aristotle and other Greek philosophers, early sociocultural-evolution theoriesthe ideas of Auguste Comte (1798–1857), Herbert Spencer (1820–1903) and Lewis Henry Morgan (1818–1881)developed simultaneously with, but independently of, the work of Charles Darwin (1809–1882) and were popular from late in the 19th century to the end of World War I. The 19th-century unilineal evolution theories claimed that societies start out in a primitive state and gradually become more civilized over time; they equated the culture and technology of Western civilization with progress. Some forms of early sociocultural-evolution theories (mainly unilineal ones) have led to much-criticised theories like social Darwinism and scientific racism, sometimes used in the past by European imperial powers to justify existing policies of colonialism and slavery and to justify new policies such as eugenics.

Most 19th-century and some 20th-century approaches aimed to provide models for the evolution of humankind as a single entity. However, most 20th-century approaches, such as multilineal evolution, focused on changes specific to individual societies. Moreover, they rejected directional change (i.e. orthogenetic, teleological or progressive change). Most archaeologists work within the framework of multilineal evolution. Other contemporary approaches to social change include neoevolutionism, dual inheritance theory, modernisation theory and postindustrial theory.

In his seminal 1976 book The Selfish Gene, Richard Dawkins wrote that "there are some examples of cultural evolution in birds and monkeys, but ... it is our own species that really shows what cultural evolution can do".Dawkins, Richard (1976). The Selfish Gene. Oxford University Press. p. 190.

Stadial theory

Eventually, in the 19th century three major classical theories of social and historical change emerged:

sociocultural evolutionism the social cycle theory the Marxist theory of historical materialism.

These theories had a common factor: they all agreed that the history of humanity is pursuing a certain fixed path, most likely that of social progress. Thus, each past event is not only chronologically, but causally tied to present and future events. The theories postulated that by recreating the sequence of those events, sociology could discover the "laws" of history.

Sociocultural evolutionism and the idea of progress

While sociocultural evolutionists agree that an evolution-like process leads to social progress, classical social evolutionists have developed many different theories, known as theories of unilineal evolution. Sociocultural evolutionism became the prevailing theory of early sociocultural anthropology and social commentary through the work of scholars like Auguste Comte (1798–1857), Edward Burnett Tylor (1832–1917), Lewis Henry Morgan (1818–1881), Benjamin Kidd (1858–1916), L. T. Hobhouse (1864–1929) and Herbert Spencer (1820–1903). Models incorporating distinct stages and ideas of linear models of progress not only had a great influence on future evolutionary approaches in the social sciences and humanities, but also shaped public, scholarly, and scientific discourse surrounding the rising individualism and "population thinking". Sociocultural evolutionism attempted to formalise social thinking along scientific lines, with the added influence from the biological theory of evolution. If organisms could develop over time according to discernible, deterministic laws, then it seemed reasonable that societies could as well. Human society was compared to a biological organism, and social-science equivalents of concepts like variation, natural selection, and inheritance were introduced as factors bearing on the progress of societies. The idea of "progress" led to that of a fixed "stages" through which human societies develop, usually numbering threesavagery, barbarism, and civilizationbut sometimes many more. At that time, anthropology was rising as a new scientific discipline, separating itself from the traditional views of "primitive" cultures that were usually based on religious views.

Already in the 18th century, some authors began to theorize on the evolution of humans. Montesquieu (1689–1755) writes about the relationship laws have with climate in particular and with the environment in general, specifically how different climatic conditions cause certain characteristics to become common among different people. He likens the development of laws, the presence or absence of civil liberty, differences in morality, and the whole development of different cultures to the climate of the respective people, concluding that the environment determines whether and how a people farms the land, which determines the way their society is built and the way their culture is constituted, or, in Montesquieu's words, the "general spirit of a nation". Jean-Jacques Rousseau (1712–1778) presents a conjectural stage-model of human sociocultural evolution: first, humans lived solitarily and only grouped when mating or raising children. Later, men and women lived together and shared childcare, thus building families, followed by tribes as the result of inter-family interactions, which lived in "the happiest and the most lasting epoch" of human history, before the corruption of civil society degenerated the species - again in a developmental stage-process.

Erasmus Darwin (1731–1802), Charles Darwin's grandfather, was an enormously influential natural philosopher, physiologist and poet whose remarkably insightful ideas included a statement of transformism and the interconnectedness of all forms of life. His works, which are enormously wide-ranging, also advance a theory of cultural transformation: his famous The Temple of Nature is subtitled 'the Origin of Society'. This work, rather than proposing in detail a strict transformation of humanity between different stages, instead dwells on Erasmus Darwin's evolutionary mechanism: Erasmus Darwin does not explain each stage one-by-one, trusting his theory of universal organic development, as articulated in the Zoonomia, to illustrate cultural development as well. Erasmus Darwin therefore flits with abandon through his chronology: Priestman notes that it jumps from the emergence of life onto land, the development of opposable thumbs, and the origin of sexual reproduction directly to modern historical events.

Another more complex theorist was Richard Payne Knight (1751–1824), an influential amateur archeologist and universal theologian. Knight's The Progress of Civil Society: A Didactic Poem in Six Books (1796) fits precisely into the tradition of triumphant historical stages, beginning with Lucretius and reaching Adam Smithbut just for the first four books. In his final books, Knight then grapples with the French revolution and wealthy decadence. Confronted with these twin issues, Knight's theory ascribes progress to conflict: 'partial discord lends its aid, to tie the complex knots of general harmony'. Competition in Knight's mechanism spurs development from any one stage to the next: the dialectic of class, land and gender creates growth. Thus, Knight conceptualised a theory of history founded in inevitable racial conflict, with Greece representing 'freedom' and Egypt 'cold inactive stupor'.

Other than Erasmus Darwin, the other pre-eminent scientific text with a theory of cultural transformation was advanced by Robert Chambers (1802–1871). Chambers was a Scottish evolutionary thinker and philosopher who, though he was then and now perceived as scientifically inadequate and criticized by prominent contemporaries, is important because he was so widely read. There are records of everyone from Queen Victoria to individual dockworkers enjoying his Vestiges of the Natural History of Creation (1844), including future generations of scientists. That The Vestiges did not establish itself as the scientific cutting edge is precisely the point, since the Vestigess influence means it was both the concept of evolution the Victorian public was most likely to experience, and the scientific presupposition laid earliest in the minds of bright young scholars.This is from James Secord's introduction to

Chambers propounded a 'principle of development' whereby everything evolved by the same mechanism and towards higher order structure or meaning. In his theory, life advanced through different 'classes', and within each class animals began at the lowest form and then advanced to more complex forms in the same class. In short, the progress of animals was like the development of a foetus. More than just an indistinct analogy, this parallel between embryology and species development had the status of a genuine causal mechanism in Chambers' theory: more advanced species developed longer as embryos into all their complexity.