If ‘no man is an island’, no group of people is an island either. Not only were contacts essential demographically for the maintenance of biological groups through provision of marriage partners, they were also a necessary element in the articulation of relationships between different members of the same community and between different communities. They served as channels for the movement of goods, and goods, i.e. artefacts, are the archaeologically concrete expression of relationships, as well as representing the supply of materials wanted for the maintenance of life.

What is being talked of here is trade, or more accurately exchange, since many, perhaps most, transactions that take place in pre-monetary societies cannot be considered commercial in the sense in which the term is understood today. Goods can move between different people, and between different groups or political units in a variety of ways, many of them not ‘economic’ at all. A range of commentators have shown how within the community most of these transactions are social in nature, depending on reciprocated giving (‘balanced reciprocity’) that reinforce particular relationships. On the other hand, exchange or procurement of goods outside the community might well witness the effects of bargain-hunting, the desire to get as good a deal as possible, perhaps at the expense of the exchange partner (‘negative reciprocity’). Both these cases assume that goods entered communities from outside, that they were available on some kind of supply network, and passed from supply or production area to consumer destination.