5.5.3 Raw material exchange

Exchange is here defined as in Renfrew (1977, 72), that is

... in the case of some distributions it is not established that the goods changed hands at all; [exchange] in this case implies procurement of materials from a distance, by whatever mechanism.

Once a territorial structure has been defined, it is possible via raw material studies to examine communication forms within and between these territories. This is usually carried out in the form of distribution analyses and with the production of fall-off curves as an important aid. The shape of fall-off curves may, for example, indicate whether exchange took place in the form of down-the-line exchange (gradually declining curve) or as directional exchange (multi-peaked curve; Renfrew 1977).

Analysis of artefact size and degree of repair and recycling with growing distance to the raw material sources may also shed light on this issue, as down-the-line exchange has a tendency to see artefacts shrink in size with growing distance. Indicators of raw material value within an exchange network are: numerical presence (a raw materials numerical presence in relation to distance to source); artefact size; artefact types (i.e. was a raw material mainly used for mundane tasks or as prestige objects); tool ratios; use-wear; and depositional patterns.

The finds from Upper Palaeolithic Howburn (Ballin et al. 2010a) are still in the process of analysis, but this case study of the site’s raw materials (dominated by exotic flints and cherts) is expected to shed light on early prehistoric exchange.


5.5.2 Territorial structures

Raw material studies may allow the definition of several higher levels of territories, such as techno-complexes or social territories (cf. Ballin 2009). Techno-complexes may be a group of social territories, which simply share a common raw material basis, which then determines specific technological approaches (e.g. the Scottish ‘quartz province’ in the north and west and the ‘chert province’ in the south).

Social territories have been suggested via their use of style. Wiessner (1983, 256), defines style as ‘...formal variation in material culture that transmits information about personal and social identity’, and she distinguishes between two forms of style, one relating to personal identity (assertive style), and the other to group identity (emblemic style) (Wiessner 1983, 257). Assertive style is of no relevance to the present case. Wiessner defines emblemic style as ‘...formal variation in material culture that has a distinct referent and transmits a clear message to a defined target population (cf. Wobst 1977, 323) about conscious affiliation or identity’ (Wiessner 1983, 257). In the following, the term ‘style’ refers exclusively to emblemic style.

In some cases, raw materials represent style, in the sense that they are markers of prehistoric group identity, and thereby also markers of social territories. If a decision to use or not use a certain raw-material is based entirely on the presence or absence of this raw-material the expression is functional, whereas a decision to give preference to a rare raw-material, or a decision to disregard a suitable abundant raw-material, are stylistic expressions (exchange of social information).

The almost total dominance of quartz in some parts of northern and western Scotland, as well as the almost total dominance of chert in southern Scotland, may be examples of the former, as in those cases few other suitable raw materials were available in the volumes needed. The use of Rùm bloodstone and Staffin baked mudstone in one specific part of the west coast of Scotland, on the other hand, may be examples of the latter, with the overlapping distribution patterns (Clarke and Griffiths 1990, ill. 94, table 29) of these two visibly distinctive raw materials probably defining one social territory.

Raw-material preference as an expression of function usually results in a gradually declining fall-off curve (Renfrew 1977, 73) with growing distance to the outcrop, whereas raw-material preference as an expression of style results in a marked drop in frequency at the borders of the social territory in question (Hodder 1979, 447), or possibly a stepped decline (O’Shea and Milner 2002, 220).