The Blombos Cave –Emergence of Human Culture, Technology, and the Neocortex

 

 

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Blombos Cave in South Africa has given us vast knowledge about our early ancestors, realigning scientific notions of the origins of early modern behavior, pushing back the dates of evidence of sophisticated cognitive actions such as flint working, ritual behaviors and personal decoration some 50,000 years earlier than the cave paintings of Upper Paleolithic Europe.


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.

"We are looking mainly at the part of South Africa where Blombos Cave is situated. We sought to find out how groups moved across the landscape and how they interacted," says Christopher S. Henshilwood, Professor at the University of Bergen (UiB) and University of the Witwatersrand and one of the authors of the articles.

The researchers from UiB and Witswatersrand have now 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?

 

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"The pattern we are seeing is that when demographics change, people interact more. For example, we have found similar patterns engraved on ostrich eggshells in different sites. This shows that people were probably sharing symbolic material culture, at certain times but not at others" says Dr Karen van Niekerk, a UiB researcher and co-author.

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.

"Contact across groups, and population dynamics, makes it possible to adopt and adapt new technologies and culture and is what describes Homo sapiens. What we are seeing is the same pattern that shaped the people in Europe who created cave art many years later," Henshilwood says. In 2015, four open access articles, with research finds from Blombos as a starting point, have been published in the journal PLOS ONE.

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 (image below), giving birth to the mind."

 

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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 a 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 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.

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 Bergen and colorado.edu

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