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The Day We Learned To Think - questions and answers

Looking at human sites in Europe from around 25,000 years ago, there is enough behavioural and physical evidence shared with recent populations to call them definitively ‘modern’ - they appear the same as hunter-gatherer societies today. This is partly shown by increased cognitive sophistication - advanced technologies, increased geographic range, specialised hunting, fishing, long-distance trade and the use of pigments. Evidence of many or all of these at a site would indicate people much like ourselves. But the killer evidence is language and the manipulation of symbols. No other animal has ever possessed an ability quite like ours. The debate then surrounds what counts as evidence of language.

Archaeologists generally agree there was an abrupt transition - a marked change in evidence in Europe - beginning 43-35,000 years ago. This is marked by:

• The appearance of sophisticated forms of representational art, ranging from elaborately carved statuettes to the cave paintings in Chauvet, France.
• A shift from tools based on simple stone flakes to the production of more regular tools purposefully ‘formed’ for particular tasks - elongated blade forms, end-scrapers, bladelets etc.
• An explosion in items whose sole function is decorative or ornamental - perforated teeth, shells, beads, pendants etc.
• The appearance of complex and extensively shaped tools made from bone, antler and ivory, also fitting into standardised types that must have served specialist purposes.
• Evidence for ornament trade or exchange networks extending over hundreds of kilometres.
• A sharp increase in the numbers of sites, reflecting a marked increase in population densities.
• The first tentative evidence of ‘ceremonial’ human burials, reflected by the presence of associated grave goods.

Neanderthals were short, stocky, heavy and muscular, possibly an adaptation to glacial Europe in which they lived. A thicker body shape reduces the surface area of the body, helping it to retain heat. Their bones were much thicker, heavier and more robust than our own, built for strength and endurance. Despite their strength and power, their bones often seem to have fractured during life. This pattern of injury is very similar to modern rodeo riders, indicating they were probably grappling large, live prey at short distances.

The neanderthal skull was long, wide and low. The two most striking features are a low sloping forehead with large brow ridges bulging out above the eyes, and a huge nose. The large nose could have been an adaptation to allow more area to warm the colder European air. Some scientists have even speculated their large noses may have contributed to their downfall - allowing airborne diseases brought by modern humans more easily into the body. Wear marks on teeth indicate they may have used their mouths as vices to clamp animal hides while they stripped the flesh.

There is fierce debate over whether or not the neanderthals possessed any of the abilities that mark modern human behaviour, and even if they did show these abilities were they simply copying from modern humans? One of the most controversial areas is the question of whether neanderthals had any kind of symbolic ability at all, let alone language.

Based on their anatomy it is theoretically possible they could have produced some form of speech. The discovery of a neanderthal hyoid bone (a bone that sits in the larynx) at Kebara in 1989 indicates they may have had a similar throat structure to humans. They also had brains of an equivalent size to modern humans, which may be another clue. However, studies of bones can only tell you so much. Without the soft tissues - the brain and the throat - we can only compare neanderthal anatomy to what we know about living animals, where these structures may have adapted to serve completely different functions.

Aside from archaeology, another line of evidence for speech would be genetics. The announcement in August 2002 of the unique form of the FOXP2 gene in modern humans was seen as a possible line of evidence for the lack of language in human ancestors. The FOXP2 gene seems to be vital in allowing human to speech to develop much more clearly, as mutations cause problems with movements of the lips and tongue as well as selection of the correct word tense.

The human version of the gene does not seem to appear until 200,000 years ago, after the neanderthals split from the ancestors of modern humans. This suggests neanderthals may have lacked a fine-tuned speech ability. However, there is unlikely to be a single 'language gene'. Language relies on an incredibly fine-tuned interaction between brain and throat, and is likely to be dependent on several genes. Further studies may show neanderthals used different genes to perform a similar function. The debate continues.

We can’t be completely sure, but the evidence is stacking up against neanderthals being our direct ancestors. A generally accepted theory is emerging that anatomically modern humans emerged in Africa some time around 120,000 years ago, and slowly replaced the more archaic species living around them in Africa. Everyone living on Earth today descends from this group. Around 45,000 years ago these modern humans started to move into the Middle East and then spread rapidly into Europe, reaching Spain around 40,000 years ago.

The neanderthals are probably descendants of earlier hominid ancestors living in Europe 400,000 years ago, and they survived until around 28,000 years ago. So there is at least a 10,000 year overlap between the arrival of modern humans and the demise of the neanderthals in Europe. What happened during this time is still a mystery. The neanderthals were always spread very thinly over the landscape, and whether they were actively pushed out or not, the last neanderthals seem to have lived on the fringes of Europe - in Spain and Portugal. There is no evidence for any contact between neanderthals and humans, though it seems likely as the two species would have occupied very similar niches.

It's doubtful that neanderthals or humans interbred - analysis of neanderthal DNA extracted from fossils so far shows little overlap with modern human populations, and backs up the anatomical differences in the fossil record. One tantalising piece of evidence comes from Lagar Velho in Portugal, where the fossil remains of a 24,500 year old boy seem to show a mixture of neanderthal and modern human characteristics, suggesting this may be a hybrid. The question of whether this is a one-off interbreeding event, the remains of a long-lived hybrid population, or simply a chunky human boy, remains to be resolved.

Jeffery Laitman’s and other comparative studies of the hominid throat suggests that a low larynx position was reached by at least 200,000 years ago. A low larynx is found in modern adult humans, and allows us a greater space to modify the air coming from our lungs and therefore produce a wide variety of speech sounds. This suggests our ancestors may have been capable of producing speech over 200,000 years ago. Whether the drive to produce speech pushed the larynx down over the course of time or whether it moved for another reason, we don’t know.

Another hint comes from brain size. Hominid brain size has nearly doubled over the past two million years, an increase far larger than that of body size. The current brain size also seems to have been reached by 200,000 years ago. Although a modern human brain size does not mean a modern human ability to use language, it seems likely that an increasing symbolic ability, related to language, may have partly driven this change.

The new evidence emerging from Africa flatly contradicts the old view that modern human behaviour has its origins with a human revolution in Europe 40,000 years ago. The discovery of the Blombos ochre, together with other similar finds, shows that symbolic behaviour must have started in Africa much earlier. Nevertheless, while there is growing consensus among archaeologists that modern behaviour must first have emerged in Africa before coming to Europe with the arrival of modern humans, there is still disagreement about exactly how and when this happened: so far, the weight of discoveries in Africa is small in comparison to the huge body of evidence found in Europe.

The discovery of pieces of jewellery from the Grotte du Renne at Arcy-sur-Cure in France has been one of the most stunning - and hotly contested - finds in the archaeology of the period of human and neanderthal coexistence. For a long time it was thought that these ornaments could not have come from neanderthals, but it has now been conclusively established that they were part of the ‘Chatelperronian’ culture, a culture distinguished by its own specific kind of stone tools that has been shown to be neanderthal. The Chatelperronian culture dates from 36,000 to 32,000, that is to a time when the neanderthals co-habited with the modern humans in Europe, and so the question is whether the ornaments demonstrate an independent symbolic capability on the part of the neanderthals, or whether they were simply copied. While they are quite unique and distinctive in their style, they remain the only unambiguous example of neanderthal symbolic artefacts, and therefore still the subject of disagreement among archaeologists.

The pieces of black manganese oxide from the cave of Pech-de-l'Azé, from the ‘Mousterian’ neanderthal culture that pre-dates the arrival of the modern humans in Europe, would support the idea of some emerging symbolic capability among neanderthal.