A distinctive “social” or “cultural” anthropology emerged in the 1920s. It was associated with the social sciences and linguistics, rather than with human biology and archaeology. In Britain in particular social anthropologists came to regard themselves as comparative sociologists, but the assumption persisted that anthropologists were primarily concerned with contemporary hunter-gatherers or pastoralists, and in practice evolutionary ways of thinking may often be discerned below the surface of functionalist argument that represents itself as ahistorical. A stream of significant monographs and comparative studies appeared in the 1930s and ’40s that described and classified the social structures of what were termed tribal societies. In African Political Systems (1940), Meyer Fortes and Edward Evans-Pritchard proposed a triadic classification of African polities. Some African societies (e.g., the San) were organized into kin-based bands. Others (e.g., the Nuer and the Tallensi) were federations of unilineal descent groups, each of which was associated with a territorial segment. Finally, there were territorially based states (e.g., those of the Tswana of southern Africa and the Kongo of central Africa, or the emirates of northwestern Africa), in which kinship and descent regulated only domestic relationships. Kin-based bands lived by foraging, lineage-based societies were often pastoralists, and the states combined agriculture, pastoralism, and trade. In effect, this was a transformation of the evolutionist stages into a synchronic classification of types. Though speculations about origins were discouraged, it was apparent that the types could easily be rearranged in a chronological sequence from the least to the most sophisticated.

There were similar attempts to classify systems of kinship and marriage, the most famous being that of the French anthropologist Claude Lévi-Strauss. In 1949 he presented a classification of marriage systems from diverse localities, again within the framework of an implicit evolutionary series. The crucial evolutionary moment was the introduction of the incest taboo, which obliged men to exchange their sisters and daughters with other men in order to acquire wives for themselves and their sons. These marriage exchanges in turn bound family groups together into societies. In societies organized by what Lévi-Strauss termed “elementary systems” of kinship and marriage, the key social units were exogamous descent groups. He represented the Australian Aboriginals as the most fully realized example of an elementary system, while most of the societies with complex kinship systems were to be found in the modern world, in complex civilizations.

American anthropology since the 1950s

In the United States a “culture-and-personality” school developed that drew rather on new movements in psychology (particularly psychoanalysis and Gestalt psychology). Later developments in the social sciences resulted in the emergence of a positivist cross-cultural project, associated with George P. Murdock at Yale University, which applied statistical methods to a sample of world cultures and attempted to establish universal functionalist relationships between forms of marriage, descent systems, property relationships, and other variables. Under the influence of the American social theorist Talcott Parsons, the anthropologists at Harvard University were drawn into team projects with sociologists and psychologists. They came to be regarded as the specialists in the study of “culture” within the framework of an interdisciplinary social science.

In the 1950s and ’60s, evolutionist ideas gained fresh currency in American anthropology, where they were cast as a challenge to the relativism and historical particularism of the Boasians. Some of the new evolutionists (led by Leslie White) reclaimed the abandoned territory of Victorian social theory, arguing for a coherent world history of human development, through a succession of stages, from a common early base. The more developed a society, the more complex its organization and the more energy it consumed. White believed that energy consumption was the gauge of cultural advance. Another tendency, led by Julian Steward, argued rather for an evolutionism that was more directly Darwinian in inspiration. Cultural practices were to be treated as modes of adaptation to specific environmental challenges. More skeptical than White about traditional models of unilineal evolution, Steward urged the study of particular evolutionary processes within enduring culture areas, in which societies with a common origin were exposed to similar ecological constraints. Students of White and Steward, including Marshall Sahlins, revived classic evolutionist questions about the origins of the state and the consequences of technological progress.

The institutional development of anthropology in Europe was strongly influenced by the existence of overseas empires, and in the aftermath of World War II anthropologists were drawn into programs in the so-called developing countries. In the United States, anthropologists had traditionally studied the native peoples of North and Central America. During World War II, however, they were called upon to apply their expertise to assist the war effort, along with other social scientists. As the United States became increasingly influential in the world, in the aftermath of the war, the profession grew explosively. In the 1950s and ’60s, important field studies were carried out by American ethnographers working in Indonesia, in East and West Africa, and in the many societies in the South Seas that had been brought under direct or indirect American control as a result of the war in the Pacific.

In the view of some critics, social and cultural anthropology was becoming, in effect, a Western social science that specialized in the study of colonial and postcolonial societies. The war in Vietnam fueled criticism of American engagement and precipitated a radical shift in American anthropology. There was general disenchantment with the project of “modernizing” the new states that had emerged after World War II, and many American anthropologists began to turn away from the social sciences.

American anthropology divided between two intellectual tendencies. One school, inspired by modern developments in genetics, looked for biological determinants of human cultures and sought to revive the traditional alliance between cultural anthropology and biological anthropology. Another school insisted that cultural anthropology should aim to interpret other cultures rather than to seek laws of cultural development or cultural integration and that it should therefore situate itself within the humanities rather than in the biological sciences or the social sciences.

Clifford Geertz was the most influential proponent of an “interpretive” anthropology. This represented a movement away from biological frameworks of explanation and a rejection of sociological or psychological preoccupations. The ethnographer was to focus on symbolic communications, and so rituals and other cultural performances became the main focus of research. Sociological and psychological explanations were left to other disciplines. In the next generation, a radically relativist version of Geertz’s program became influential. It was argued that cultural consensus is rare and that interpretations are therefore always partial. Cultural boundaries are provisional and uncertain, identities fragile and fabricated. Consequently ethnographers should represent a variety of discordant voices, not try to identify a supposedly normative cultural view. In short, it was an illusion that objective ethnographic studies could be produced and reliable comparisons undertaken.

European anthropology since the 1950s

In Europe the social science program remained dominant, though it was revitalized by a new concern with social history. Some European social scientists became leaders of social thought, among them Pierre Bourdieu, Mary Douglas, Louis Dumont, Ernest Gellner, and Claude Lévi-Strauss. Elsewhere, particularly in some formerly colonial countries in Latin America, Asia, and Africa, local traditions of anthropology established themselves. While anthropologists in these countries were responsive to theoretical developments in the traditional centres of the discipline, they were also open to other intellectual currents, because they were typically engaged in debates with specialists from other fields about developments in their own countries.

Empirical research flourished despite the theoretical diversity. Long-term fieldwork was now commonly backed up by historical investigations, and ethnography came to be regarded by many practitioners as the core activity of social and cultural anthropology. In the second half of the 20th century, the ethnographic focus of anthropologists changed decisively. The initial focus had been on contemporary hunter-gatherers or pastoralists. Later, ethnographers specialized in the study of formerly colonized societies, including the complex villages and towns of Asia. From the 1970s fieldwork began increasingly to be carried out in European societies and among ethnic minorities, church communities, and other groups in the United States. In the formerly colonized societies, local anthropologists began to dominate ethnographic research, and community leaders increasingly insisted on controlling the agenda of field-workers.

The liveliest intellectual developments were perhaps to be found beyond the mainstream. Fresh specializations emerged, notably the anthropology of women in the 1970s and, in the following decades, medical anthropology, psychological anthropology, visual anthropology, the anthropology of music and dance, and demographic anthropology. The anthropology of the 21st century was polycentric and cosmopolitan, and it was not entirely at home among the biological or social sciences or in the humanities.