2018-10-14 14:17:19 • ID: 2030
Handaxe Refinement and long durée in the Acheulean
This is a beautiful elongated 25 cm long refined Handaxe, found 40 yrs ago in the Erg Murzuq in Libya. This enormous sand sea is a massive, “monolithic” desert east of the Acacus mountain range and south of Wadi Metkhendoush. See here: 1030 and here: 1751 .
Please note the thinness, straight edges, and the high degree of symmetry which are important for the following discussion.
"Archaeological evidence indicates that the refinement and symmetry of Acheulean bifaces were properties intentionally imposed by hominins.
Given the cutting function of handaxes, it is likely that a straight edge was also a desirable feature for Acheulean knappers.
If the goal in biface manufacture was to create thin, symmetrical, straight-edged pieces, then the lack of motivation amongst hominins to enhance such variables can be disregarded as a mitigating factor, as would be necessary with behavioural studies of living subjects" (Shipton et al 2018).
Therefore, is seems reasonable that refinement of a handaxe could be defined by thinness, edge straightness, and symmetry.
Variability of Handaxe refinement is a multivariate function of raw material, blank morphology, individual and collective skills, site function, duration of stay, functional requirements and different percussion techniques, that were used.
These factors are only captured insufficiently in any evaluation of Handaxe refinement. Therefore, it is not surprising that studies with different outcome exist.
To complicate the issue further, some studies used old biased collection while others did not. Some studies used quantitative measurements and other did not.
The definition of refinement differs between studies, which makes the situation even more complicated.
Last but not least it is an inevitable selection bias to concentrate on some sites and neglect others with similar data quality and excavation history.
Since Victor Commont until the early years of A. Tuffreau, it was a dogma in French Prehistoric research, that the staircase of the Somme river terraces shows a succession of initial crude and successive finer handaxes. Newer studies could not confirm this trend.
The same holds through for the British Handaxes. Boxgrove as early as MIS 13 shows highly sophisticated material.
Iovita at al. recently quantitatively assessed symmetry of the well excavated sites of Boxgrove (500 k.a.) and Noira, in central France, with strata between 700 k.a. and 500 k.a. old. They found an increase of symmetry over time (Iovita et al. 2017).
Anyhow we do not know how these results were influenced by confounding factors and the bias of concentrating on these sites.
Going to East Africa, where Handaxe production began, Louis Leakey’s seminal 1951 publication of the Olduvai Gorge bifaces was focused on 11 progressive stages of handaxe refinement, with the most beautiful types on the top of Bed IV. The Olduvai specimens cover the temporal range from c. 1.7 to 0.6 my.
Recently low biased collections of four East African Acheulean sites: Olduvai Gorge (Bed II and IV), Olorgesailie, Kariandusi, and Isinya (the last three sites roughly contemporaneous with Olduvai Bed III) where quantitatively evaluated for Handaxe refinement over time. One strength of the study was the careful selection of samples and that statistical results were corrected for confounding factors like blank morphology and raw materials that were used.
Factors like raw material were of significant importance for distinct parameters of refinement (thinness, edge straightness, and symmetry) at some sites, but not at Olduvai.
In the long term an increase of refinement was noted at Olduvai, but not at collections from the other sites, which represent a shorter time-frame, and were more dependent on confounding factors.
Possible explanations for the increase of refinement at Olduvai include the maturation of distinct neuronal networks, the evolution of a prolonged adolescence history and the invention of new knapping techniques (soft hammer) over long timescales.
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