He had found them in prehistoric lake deposits along with the bones of extinct animals and concluded that they were made by people "who had not the use of metals" and that they belonged to a "very ancient period indeed, even beyond the present world".

[12][13] In individual regions, this dating can be considerably refined; in Europe for example, it was thought that Acheulean methods did not reach the continent until around 500,000 years ago.

[13] Relative dating techniques (based on a presumption that technology progresses over time) suggest that Acheulean tools followed on from earlier, cruder tool-making methods, but there is considerable chronological overlap in early prehistoric stone-working industries, with evidence in some regions that Acheulean tool-using groups were contemporary with other, less sophisticated industries such as the Clactonian[14] and then later with the more sophisticated Mousterian, as well.

It is therefore important not to see the Acheulean as a neatly defined period or one that happened as part of a clear sequence but as one tool-making technique that flourished especially well in early prehistory.

The enormous geographic spread of Acheulean techniques also makes the name unwieldy as it represents numerous regional variations on a similar theme.

The term Acheulean does not represent a common culture in the modern sense, rather it is a basic method for making stone tools that was shared across much of the Old World.

[citation needed] Mode 3 technology emerged towards the end of Acheulean dominance and involved the Levallois technique, most famously exploited by the Mousterian industry.

Materials used were determined by available local stone types; flint is most often associated with the tools but its use is concentrated in Western Europe; in Africa sedimentary and igneous rock such as mudstone and basalt were most widely used, for example.

[23] In all cases the toolmakers worked their handaxes close to the source of their raw materials, suggesting that the Acheulean was a set of skills passed between individual groups.

[citation needed] Use-wear analysis on Acheulean tools suggests there was generally no specialization in the different types created and that they were multi-use implements.

Sites such as Melka Kunturé in Ethiopia, Olorgesailie in Kenya, Isimila in Tanzania, and Kalambo Falls in Zambia have produced evidence that suggests Acheulean hand-axes might not always have had a functional purpose.

[31][additional citation(s) needed] Mimi Lam, a researcher from the University of British Columbia, has suggested that Acheulean hand-axes became "the first commodity: A marketable good or service that has value and is used as an item for exchange.

"[32] Fertile Crescent: Europe: Africa: Siberia: The geographic distribution of Acheulean tools – and thus the peoples who made them – is often interpreted as being the result of palaeo-climatic and ecological factors, such as glaciation and the desertification of the Sahara Desert.

[33] Acheulean stone tools have been found across the continent of Africa, save for the dense rainforest around the River Congo which is not thought to have been colonized by hominids until later.

Later finds of Acheulean tools at Chongokni in South Korea and also in Mongolia and China, however, cast doubt on the reliability of Movius's distinction.

[citation needed] Late Acheulean tools were still used by species derived from H. erectus, including Homo sapiens idaltu and early Neanderthals.

[39] Others argue that there is no correlation between spatial abilities in tool making and linguistic behaviour, and that language is not learned or conceived in the same manner as artefact manufacture.

[40] Lower Palaeolithic finds made in association with Acheulean hand-axes, such as the Venus of Berekhat Ram,[41] have been used to argue for artistic expression amongst the tool users.

The incised elephant tibia from Bilzingsleben[42] in Germany, and ochre finds from Kapthurin in Kenya[43] and Duinefontein in South Africa,[44] are sometimes cited as being some of the earliest examples of an aesthetic sensibility in human history.

There are numerous other explanations put forward for the creation of these artefacts; however, evidence of human art did not become commonplace until around 50,000 years ago, after the emergence of modern Homo sapiens.

[46] Excavations at the Bnot Ya'akov Bridge site, located along the Dead Sea rift in the southern Hula Valley of northern Israel, have revealed evidence of human habitation in the area from as early as 750,000 years ago.

[47] Archaeologists from the Hebrew University of Jerusalem claim that the site provides evidence of "advanced human behavior" half a million years earlier than has previously been estimated.

Cave sites were exploited for habitation, but the hunter-gatherers of the Palaeolithic also possibly built shelters such as those identified in connection with Acheulean tools at Grotte du Lazaret[52] and Terra Amata near Nice in France.

The presence of the shelters is inferred from large rocks at the sites, which may have been used to weigh down the bottoms of tent-like structures or serve as foundations for huts or windbreaks.