The role of tactile perception during stone-polishing in Aegean prehistory (5th–4th millennium B.C.)

Abstract

► Ancient polished surfaces were classified according to specific roughness parameters . ► Prehistoric polishing techniques were identified using the method of continuous wavelets. ► We have developed an instrumented human finger in order to obtain tactile signatures of sheen. ► Sensorial signatures obtained by the human finger coincide with the roughness signatures. ► We showed the acuity of touch to evaluate polished surfaces. Although touch has occupied the lowest range in the scale of senses until the Renaissance period in the Western World, tactile perception was pre-eminent in Antiquity when tactile acuity reflected superior intelligence (cf. Aristotle, On the Soul II, 9, 421a 19–26). Our study on prehistoric stone-polishing techniques in the Greek Cyclades enables us to propose that prehistoric craftsmen were using haptic criteria in order to appreciate polished surfaces and that apprenticeship and the transmission of know-how required highly developed sensory abilities. We have made precise observations of polished diasporite celts and polishers of the Final Neolithic (end of the 5th millennium B.C.) and Early Bronze Age (4th millennium B.C.) periods and then went on to experiments to test various ways of polishing diasporite (982 HV) with different types of abrasives (sand rich in quartz, ground corundum and emery). Reference surfaces for each procedure have been obtained. Texture, radiance and tactile perception of these polished surfaces have been analysed. In order to reveal the morphological signature of polishing procedures and to interpret the traces on the archaeological tools, we applied a multi-scale analysis using the method of continuous wavelets transform. The surface radiance has been quantified with a specific optical system. This methodology completed existing sheen analysis on prehistoric tools, which until now has been based exclusively on qualitative observation. Finally, an “instrumented human finger” considered the sensorial perception of the polish. Optical signatures appear intimately related to the nature of the lubricant, though sensorial signatures obtained by the human finger coincide with the roughness signature.