Fifty shades of ochre: colour, chemistry and cognition (original) (raw)

Ochre pieces found at Middle Stone Age (MSA) and Middle Palaeolithic sites show a range of colours, use-traces and applications. Ochre assemblages provide a way to explore some of the behavioural and cognitive changes that took place during the Late Pleistocene – a time of significant behavioural developments, and important cognitive implications for Homo sapiens and Neanderthals. Ochre pieces bearing engraved ‘designs’ and the preferential use of bright-red and shiny (micaceous) ochre have resulted in symbolic interpretations of the uses of ochre. But the colour of ochre can tell us more about ochre manipulation use than just colour preferences and potentially symbolic uses. Reconstructing the behavioural aspects of ochre use – such as selection preferences, collection range and source, pre-use manipulation such as heat treatment, and processing procedures – can offer valuable insight into the cognitive capabilities of the ochre users. Rose Cottage Cave and Sibudu, South Africa, contain significant and long MSA sequences dating between ~96 000 ya and 30 000 ya. They yield large ochre assemblages with a range of physical attributes and use-traces. Through experimental ochre use and heating of geological ochre samples we learned what features to look for to identify heat treatment and ochre processing techniques. With this knowledge, the physical attributes, use-traces and chemical signatures of the archaeological ochre were then examined. These multi-analytical data were combined to determine ochre selection preferences, heat treatment probabilities and ochre processing techniques used at the sites. By obtaining this valuable information from the ochre pieces we have been able to explore questions of the skill, knowledge and cognitive abilities required to perform activities involving ochre.