New evidence confirms that notable and ancient intergroup cultural differences shaped the later stages of human evolution in Africa.
Our species, Homo sapiens, appeared in Africa about 300 years. Objects that early humans made and used, known as the Middle Stone Age (Middle Paleothic) material culture, are found throughout much of Africa and are associated with a wide range of innovations.
Among these, we must mention the bow and arrow technology, tool shapes specialized, long-distance transport of objects, such as sea shells andobsidian, personal adornments, the use of pigments, finally the water storage, and art. Although it is possible that other ancestors of modern man contributed to this material culture of Africa, some of the earliest stone tools of the Middle Stone Age have been unearthed along with the oldest fossils. Homo sapiens discovered until now.
According to the textbooks, around 40 years ago, the Middle Stone Age was long over in Africa. This is an important milestone in the history of our species: the end of the first and longest culture associated with humanity, and the foundation of all subsequent innovations and of the material culture that defines us today.
Despite its central role in human history, we find it difficult to understand how the Middle Stone Age ended. Coming to know could tell us how different groups were distributed across the landscape, how they were able to exchange ideas and pass genes on to each other, and how these processes shaped later stages of human evolution.
Unfortunately, vast swathes of Africa remain almost entirely empty on the map with regard to such a distant prehistory, making it difficult to study these cases. Research has tended to focus on regions such as East Africa, where the conservation of artefacts is considered to be of high standard, and the risks consequently minimized and the gains maximized naturally. However, due to the emerging consensus that all of Africa played a role in the origins of humanity, we can no longer afford to neglect large areas of the continent if we are to reconsider our evolution. in a realistic setting.
It is for all these reasons that my colleagues and I have focused on West Africa, one of the least understood regions of Africa in terms of human evolution. In addition, our recent communication validate them previous assertions from a rich Middle Stone Age past.
New work carried out in Senegal
In 2014, our work in Senegal resulted in the discovery of a site in the north of the country which seems to suggest that the Middle Stone Age ended in this area much more recently than the textbooks suggest. In West Africa, several older dates had been mentioned in the past, however this work had been largely discarded due to problematic dating, carried out before the establishment of current standards.
The dating of Ndiayène Pendao indicates that the site had approximately 12 years. Yet material culture was traditionally from the Middle Stone Age, without any tools or means of production dating from the Late Stone Age (Upper Paleolitic). In 2016 and 2018, we returned to the field to search for sites in different regions of Senegal and around various river systems, near tributaries to Senegal and The Gambia. Indeed, freshwater sources were essential for people in the past, just as they are today; river terraces often also offer excellent conservation conditions and are therefore ideal places for researching archaeological sites.
The Laminia site in The Gambia had never been dated. We carried out a detailed evaluation of its rock layers, in order to obtain dating samples that we could confidently relate to the artefacts. Samples taken from this site are 24 years old, confirming the presence of an earlier Middle Stone Age in the region.
The Saxomununya site gave us an even bigger surprise. Like classic Middle Stone Age artifacts, such as Levallois points and retouched end scrapers, coming from this site, were unearthed on a new terrace of the Falémé river but also inside, it became obvious that the site was relatively recent. However, dating to 11 years ago puts the earliest Middle Stone Age into the Holocene epoch, the period after the last great ice age. It was the first time that such an ancient material culture was discovered in such recent times in Africa. This finding indicated that Ndiayène Pendao's results were neither a coincidence nor an error.
According to these results, the last known appearance of the Middle Stone Age therefore dates back 20 years, which is astounding. At the same time, the work of Senegalese colleagues seems to evoke a first appearance of the late stone age just as late, around 11 years old, less ancient than in most other parts of Africa.
Why did the Middle Stone Age last so long and why did the Late Stone Age start so late?
Part of the answer to the first question may lie in the fact that parts of West Africa appear to have been less affected by the extremes of repeated cycles of climate change. These factors may have created stable environmental conditions over a long period of time. Because of this stability, the “toolbox” refined and used successfully for millennia, perhaps did not need to evolve, independently of the complex society that gave rise to these tools.
As for the second question, its answer lies in the fact that this region of Africa was relatively isolated. To the north it meets the Sahara Desert and to the east there are the rainforests of Central Africa, which were often cut off from the rainforests of West Africa during times of drought. About 15 years ago, however, a considerable increase moisture and forest vegetation has been recorded in Central and West Africa. Different areas have thus been linked, creating corridors conducive to the dispersal of human populations. It may have sounded the death knell for humanity's first and oldest cultural repertoire and initiated a new period of genetic and cultural mixing.
It is clear that the simple, unilinear model of cultural evolution towards "modernity", which has long prevailed, is not supported by the evidence. Groups of hunter-gatherers steeped in radically different technological traditions, may have occupied neighboring regions of Africa for thousands of years, and sometimes shared the same regions. In addition, it is possible that long isolated regions were important reservoirs. cultural and genetic diversity. This corresponds well to genetic studies and could have been a determining factor in the success of our species. Our results remind us of the risks associated with refusing to take account of map gaps.
Eleanor scerri, Independent group leader, Max Planck Institute for the Science of Human History
This article is republished from The Conversation under a Creative Commons license. Read original article.