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2020-11-03 06:55:19   •   ID: 2209

Celebrating the 10th anniversary of Aggsbachs Blog: A MTA Handaxe from the Creysse Area

Figure 1
Figure 1 and 2: For a modern observer this is a beautiful MTA Biface, found in the Creysse Area in 1923 about 1 km S/W of the famous Barbas site, excavated during the last decennia.

Indeed, for a contemporary observer, this Biface has a special appeal by its careful design.

But was the creation of a thin, symmetric artifact really the intention of the Neandethal who made this artifact?

Anyhow, actualistic studies in living AHMs showed that most people prefer symmetrical to asymmetrical handaxes, in particular young females (see external link).

Who manufactured Handaxes during the Paleolithic? Acheulean handaxes are thought to have been produced by different extinct hominin species, Homo erectus sensu lato (or Homo Rudolphensis in Africa and Homo Erectus in Asia) and Homo heidelbergensis sensu lato (Homo Rhodensis in Africa and Homo Heidelbergensis in Europe). MTA Handaxes in Europe were exclusively made by Neanderthals.

It is highly possible that archaic Homo sapiens and other Archaic Middle Pleistocene Hominides in Africa and Asia also used the Handaxe concept. The Paleolithic hand axe is thus the tool with the longest history in mankind.

The Transmission of Handaxe Making: One important issue regarding the conservatism of Acheulean handaxes is the question if handaxes are a cultural object, transmitted by learning from one generation to another or the consequence of genetic based transmission. There is evidence for and against these hypotheses as described by Corbey et al. (2016), who in depth introduces into the pros and cons for both positions.

Evolutionary Background of Symmetry:

Figure 2
Symmetry is an eye-catching feature both of plant and of animal design, but its causes and evolutionary meaning are not well understood.

According to theoretical considerations Symmetry should imply an Evolutionary advantage.

There are Genetic prerequisites for a symmetrical design of an animal, that have been described during the last years: the so-called gene regulatory networks.

They determine which protein-coding gene will be transcribed, and when, in which cells and how much protein will be produced. The transcription of protein-coding genes is directed by regulatory sequences of the DNA.

The different types of regulatory regions (for example, enhancers, promoters, silencers, insulators and so on; e.g.) are activated by the binding of specific proteins called transcription factors (TFs).

The binding of a proper combination of the given TFs to the regulatory regions can either activate, modulate or inhibit the transcription of the target gene. I propose that the animal genome, as such, is capable of expressing both radial and bilateral symmetries, and deploys them according to the functional requirements which must be satisfied by both the anatomical structure and body as a whole
. (Hollo 2016).

In a later paper Holo argued that Symmetry is the product of the interplay between gene regulatory networks but also a response to mechanical forces (Holo 2017).

From an evolutionary perspective many important environmental elements are symmetrical and sensitivity to symmetry may have evolved because it is important for discriminating living organisms from inanimate objects. This issue was already discussed here: 1373

Sensitivity to symmetry is a fundamental element of mammalian visual perception, controlled by neuronal network mainly residing in the medial occipital gyrus.

Became Symmetry the Aim of Handaxe production over time ?

It is debatable if Symmetry increased over time, an issue that was already addressed in this Blog here: 2030 . Currently in 2020 it seems that the much quoted belief that handaxes become more refined and symmetrical over time has no substantial body of data to support it.

Was Symmetry the Aim of Handaxe production?

In an experimental setting Bachin evaluated if a set of morphological variables, including symmetry, influenced the effectiveness of handaxes for butchery.

From her experiments Machin et al. concluded: while frontal symmetry may explain a small amount of variance in the effectiveness of handaxes for butchery, a large percentage of variance remains unexplained by symmetry or any of the other morphological variables under consideration a large percentage of variance remains unexplained by symmetry or any of the other morphological variables under consideration (Machin et al. 2006).

This study adds evidence to an increasing corpus of data, published during the last years, that showed that Symmetry per se was not a requirement of success in the Handaxes functionality.

These experimental results let us suggest that the careful creation of symmetrical handaxes may have rewarded its maker by a social, and on a more generalized level, a symbolic surplus- in other words: " Symmetry is its own reward" Neurophysiological via the Dopaminerge reward system (White et al. 2018).

By the way: These post was Nr. 700 during the 10th anniversary of Aggsbachs Blog