Michael Balter covers a new paper on MSA shell beads by Marian Vanhaeren and colleagues: "Human ancestors were fashion-conscious". The study involves beads from Still Bay levels at Blombos Cave, South Africa.
To get an idea of how the shell beads were worn, Vanhaeren and her colleagues examined the wear (smoothing) around the perforations and on other parts of the shells. They then carried out additional experiments in which N. kraussianus shells were shaken together for many hours at a time and exposed to a diluted vinegar solution meant to mimic human sweat, among other tests, while strung together in various ways.
By stringing the shells themselves in various configurations, the team identified six possible ways that the beads could have been worn, including tying a knot around each shell, stringing them in a continuous row, braiding them with two strings at a time, and reversing the orientations of the shells to each other. Then, by analyzing the wear on the shells caused by these arrangements, Vanhaeren and colleagues determined just how the beads were strung. "In the lower [older] layers, the shells hang free on a string with their flat, shiny [sides] against each other," Vanhaeren says. But like all fashions, that one didn't last long: In the two upper, younger layers, "the shells are knotted together two by two, with their shiny side up" (see photos).
That's a pretty clever approach. With these beads it is not possible to trace stylistic aspects of form directly; they are just not subject to enough human alteration. But the traces of wear allow an indirect assessment of stylistic variation, in the way that they were strung. It makes for one of the earliest examples of studying stylistic variation over a time range in an archaeological context.