Is the nuclear family the universal or original human family form, as much mid-twentieth-century family sociology assumed, or is the extended family the more common arrangement historically and cross-culturally?

George Murdock's mid-twentieth-century comparative study of 250 societies found some form meeting his definition of family in every one, and historians Alan Macfarlane and Peter Laslett argue the nuclear household was already primary in England from at least the thirteenth century, evidence often read as supporting the nuclear family as a basic or even universal unit. Against this, the source itself states that some sociologists and anthropologists consider the extended family, not the nuclear family, to be the most common family structure in most cultures and at most times for humans, and a 4,600-year-old German burial site, sometimes cited as the earliest known nuclear-family unit, is explicitly cautioned against being read as establishing the nuclear family as a universal or the most ancient institution.