one of the foundational works in the anthropological study of kinship was morgan's "systems of consanguinity and affinity of the human family" (1871). as is the case with other social sciences, anthropology and kinship studies emerged at a time when the understanding of the human species' comparative place in the world was somewhat different from today's. evidence that life in stable social groups is not just a feature of humans, but also of many other primates, was yet to emerge and society was considered to be a uniquely human affair. as a result, early kinship theorists saw an apparent need to explain not only the details of "how" human social groups are constructed, their patterns, meanings and obligations, but also "why" they are constructed at all. the "why" explanations thus typically presented the fact of life in social groups ("which appeared to be unique to humans") as being largely a result of human ideas and values.