“Before this discovery, Palaeolithic archaeologists have for a long time been convinced that unambiguous symbols first appeared when Homo sapiens entered Europe, about 40 000 years ago, and later replaced local Neanderthals,” says Christopher Henshilwood at the Centre for Early Sapiens Behaviour and University of the Witwatersrand. “Recent archaeological discoveries in Africa, Europe and Asia, in which members of our team have often participated, support a much earlier emergence for the production and use of symbols.”
Since its discovery in the early 1990s, Blombos Cave, about 300 kilometers east of Cape Town, South Africa, has yielded important new information on the behavioral evolution of the human species. The cave site was first excavated in 1991 and field work has been conducted there on a regular basis since 1997 – and is on-going. Blombos contains Middle Stone Age deposits currently dated at between 100,000 and 70,000 years, and a Later Stone Age sequence dated at between 2,000 and 300 years.
This earliest evidence of a drawing made by humans consisted of three red lines cross-hatched with six separate lines, was intentionally drawn on a smooth silcrete flake about 73 000 years ago. This predates previous drawing from Africa, Europe and Southeast Asia by at least 30,000 years.
The researchers have been looking closer at technology used by different groups in this and other regions in South Africa, such as spear points made of stone, as well as decorated ostrich eggshells, to determine whether there was an overlap and contact across groups of Middle Stone Age humans. How did they make contact with each other? How would contact across groups affect one group? How did the exchange of symbolic material culture affect the group or groups?
This sharing of symbolic material culture and technology also tells us more about Homo sapiens’ journey from Africa, to Arabia and Europe. Contact between cultures has been vital to the survival and development of our common ancestors Homo sapiens. The more contact the groups had, the stronger their technology and culture became.
The drawing on the silcrete flake was a surprising find by archaeologist Dr. Luca Pollarolo, an honorary research fellow at the University of the Witwatersrand (Wits), while he painstakingly sifted through thousands of similar flakes that were excavated from Blombos Cave at the Wits University satellite laboratory in Cape Town.
“I think I saw more than ten thousand artifacts in my life up to now, and I never saw red lines on a flake,” said Dr. Pollarolo. “I could not believe what I had in my hands.”
Blombos Cave has been excavated by Professor Christopher Henshilwood and Dr. Karen van Niekerk since 1991. It contains material dating from 100 000—70 000 years ago, a time period referred to as the Middle Stone Age, as well as younger, Later Stone Age material dating from 2000—300 years ago.
Henshilwood holds a Research Chair at the University of Witwatersrand in South Africa, and is the Director of a newly granted Centre of Excellence at the University of Bergen, Centre for Early Sapiens Behaviour (SapienCE). Van Niekerk is a Principal Investigator at SapienCE. The team’s findings on the 73 000-year-old drawing was published in the journal, Nature, on 12 September may provide insight into the origins of humanity’s use of symbols, which laid the foundation for language, mathematics and civilization.
“We knew a lot of things Homo sapiens could do, but we didn’t know they could do drawings back then,” said Henshilwood, an archaeologist from the University of Bergen in Norway and lead author of the study.
Realizing that the lines on the flake were unlike anything that the team had come across from the cave before, they set out to answer the questions it posed. Were these lines natural, or a part of the matrix of the rock? Were they, perhaps, made by humans living in Blombos Cave 73 000 years ago? If humans made the lines, how did they make them, and why?
Under the guidance of Professor Francesco d’Errico at the PACEA lab of the University of Bordeaux, France (the second author of the paper) the team examined and photographed the piece under a microscope to establish whether the lines were part of the stone or whether it was applied to it. To ensure their results, they also examined the piece by using RAMAN spectroscopy and an electron microscope. After confirming the lines were applied to the stone, the team experimented with various paint and drawing techniques and found that the drawings were made with an ochre crayon, with a tip of between 1 and 3 millimetres thick. Further, the abrupt termination of the lines at the edge of the flake also suggested that the pattern originally extended over a larger surface, and may have been more complex in its entirety.
The earliest known engraving, a zig-zag pattern, incised on a fresh water shell from Trinil, Java, was found in layers dated to 54 000 years ago and a recent article has proposed that painted representations in three caves of the Iberian Peninsula were 64,000 years old and therefore produced by Neanderthals. This makes the drawing on the Blombos silcrete flake the oldest drawing by Homo sapiens ever found.
Although abstract and figurative representations are generally considered conclusive indicators of the use of symbols, assessing the symbolic dimension of the earliest possible graphisms is tricky.
Symbols are an inherent part of our humanity. They can be inscribed on our bodies in the form of tattoos and scarifications or cover them through the application of particular clothing, ornaments and the way we dress our hair.
Language, writing, mathematics, religion, laws could not possibly exist without the typically human capacity to master the creation and transmission of symbols and our ability to embody them in material culture. Substantial progress has been made in understanding how our brain perceives and processes different categories of symbols, but our knowledge on how and when symbols permanently permeated the culture of our ancestors is still imprecise and speculative.
The archaeological layer in which the Blombos drawing was found also yielded other indicators of symbolic thinking, such as shell beads covered with ochre, and, more importantly, pieces of ochres engraved with abstract patterns. Some of these engravings closely resemble the one drawn on the silcrete flake.
“This demonstrates that early Homo sapiens in the southern Cape used different techniques to produce similar signs on different media,” says Henshilwood. “This observation supports the hypothesis that these signs were symbolic in nature and represented an inherent aspect of the behaviorally modern world of these African Homo sapiens, the ancestors of all of us today.”
From earlier research, there is archaeological evidence for the evolution of a human “super-brain” no later than 75,000 years ago that spurred a modern capacity for novelty and invention, according to John Hoffecker, an archaeologist at the University of Colorado.
Hoffecker says there is abundant fossil and archaeological evidence for the evolution of the human mind, including its unique power to create a potentially infinite variety of thoughts expressed in the form of sentences, art and technologies. He attributes the evolving power of the mind to the formation of what he calls the “super-brain,” or collective mind, an event that took place in Africa no later than 75,000 years ago.
An internationally known archaeologist who has worked at sites in Europe and the Arctic, Hoffecker said the formation of the super-brain was a consequence of a rare ability to share complex thoughts among individual brains.
“Humans obviously evolved a much wider range of communication tools to express their thoughts, the most important being language,” said Hoffecker, a fellow at CU’s Institute of Arctic and Alpine Research. “Individual human brains within social groups became integrated into a neurologic Internet of sorts, giving birth to the mind.
The neocortex, Latin for “new bark,” is our third, newly human brain in terms of evolution. It is what makes possible our judgments and our knowledge of good and evil. It is also the site from which our creativity emerges and home to our sense of self.
The neocortex says Carl Sagan in his iconic Cosmos, is where “matter is transformed into consciousness.” It comprises more than two-thirds of our brain mass. The realm of intuition and critical analysis,–it is the Neocortex where we have our ideas and inspirations, where we read and write, where we compose music or do mathematics. “It is the distinction of our species,” writes Sagan,”the seat of our humanity. Civilization is the product of the cerebral cortex.”
Each cubic millimeter of tissue in the neocortex, reports Michael Chorost in World Wide Mind, contains between 860 million and 1.3 billion synapses. Estimates of the total number of synapses in the neocortex range from 164 trillion to 200 trillion. The total number of synapses in the brain as a whole is much higher than that. The neocorex has the same number of neurons as the Milky Way Galaxy has stars: 100 billion.
One researcher estimates that with current technology it would take 10,000 automated microscopes thirty years to map the connections between every neuron (image above) in a human brain, and 100 million terabytes of disk space to store the data.
Self-aware, language-using, tool-making brains are very new in the evolutionary timeline, some 200,000-years old. Most of the neurons in the neocortex have between 1,000 and 10,000 synaptic connections with other neurons. Elsewhere in the brain, in the cerebellum, one type of neuron has 150,000 to 200,000 synaptic connections with other neurons. Even the lowest of these numbers seems hard to believe. One tiny neuron can connect to 200,000 neurons. The below image represents the neurons of the human brain (courtesy of Paul De Koninck from www.greenspine.ca).
While anatomical fossil evidence for the capability of speech is controversial, the archaeological discoveries of symbols coincides with a creative explosion in the making of many kinds of artifacts. Abstract designs scratched on mineral pigment show up in Africa about 75,000 years ago and are widely accepted by archaeologists as evidence for symbolism and language. “From this point onward there is a growing variety of new types of artifacts that indicates a thoroughly modern capacity for novelty and invention.”
The roots of the mind and the super-brain lie deep in our past and are likely tied to fundamental aspects of our evolution like bipedalism and making stone tools, he said. It was from the making of tools that early humans first developed their ability to project complex thoughts or mental representations outside the individual brain — our own version of the honeybee waggle dance, Hoffecker said.
While crude stone tools crafted by human ancestors beginning about 2.5 million years ago likely were an indirect consequence of bipedalism — which freed up the hands for new functions — the first inklings of a developing super-brain likely began about 1.6 million years ago when early humans began crafting stone hand axes, thought by Hoffecker and others to be one of the first external representations of internal thought.
Ancient hand axes achieved “exalted status” as mental representations since they bear little resemblance to the natural objects they were made from — generally cobbles or rock fragments. “They reflect a design or mental template stored in the nerve cells of the brain and imposed on the rock, and they seemed to have emerged from a strong feedback relationship among the hands, eyes, brains and the tools themselves,” he said.
The emerging modern mind in Africa was marked by a three-fold increase in brain size over 3-million-year-old human ancestors like Lucy, thought by some to be the matriarch of modern humans. Humans were producing perforated shell ornaments, polished bone awls and simple geometric designs incised into lumps of red ochre by 75,000 years ago. “With the appearance of symbols and language — and the consequent integration of brains into a super-brain — the human mind seems to have taken off as a potentially unlimited creative force,” he said.
The dispersal of modern humans from Africa to Europe some 50,000 to 60,000 years ago provides a “minimum date” for the development of language, Hoffecker speculated. “Since all languages have basically the same structure, it is inconceivable to me that they could have evolved independently at different times and places.”
The Daily Galaxy via University of the Witwatersrand, University of Bergen and Colorado.edu
Image credit: at top of page, With thanks to Reuters.
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