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. Scientists seeking to understand the origin of the human mind may want to look to honeybees -- not ancestral apes -- for at least some of the answers, according to a Hoffecker.
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. Among other creatures on Earth, the honeybee may be the best example of an organism that has mastered the trick of communicating complex information -- including maps of food locations and information on potential nest sites from one brain to another -- using their intricate "waggle dance."
"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 image below illustrates the neocortex (Tamily Weissman, Jeff Lichtman, and Joshua Sanes).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."
A 2007 study led by Hoffecker and colleagues at the Russian Academy of Sciences pinpointed the earliest evidence of modern humans in Europe dating back 45,000 years ago. Located on the Don River 250 miles south of Moscow, the multiple sites, collectively known as Kostenki, also yielded ancient bone and ivory needles complete with eyelets, showing the inhabitants tailored furs to survive the harsh winters.
The team also discovered a carved piece of mammoth ivory that appears to be the head of a small figurine dating to more than 40,000 years ago. "If that turns out to be the case, it would be the oldest piece of figurative art ever discovered," said Hoffecker, whose research at Kostenki is funded in part by the National Science Foundation.
The finds from Kostenki illustrate the impact of the creative mind of modern humans as they spread out of Africa into places that were sometimes cold and lean in resources, Hoffecker said. "Fresh from the tropics, they adapted to ice age environments in the central plain of Russia through creative innovations in technology."
Ancient musical instruments and figurative art discovered in caves in France and Germany date to before 30,000 years ago, he said. "Humans have the ability to imagine something in the brain that doesn't exist and then create it," he said. "Whether it's a hand axe, a flute or a Chevrolet, humans are continually recombining bits of information into novel forms, and the variations are potentially infinite."
While the concept of a human super-brain is analogous to social insects like bees and ants that collectively behave as a super-organism by gathering, processing and sharing information about their environment, there is one important difference, Hoffecker said. "Human societies are not super-organisms -- they are composed of people who are for the most part unrelated, and societies filled with competing individuals and families."
Since the emergence of the modern industrial world beginning roughly 500 years ago, creativity driven by the human super-brain has grown by leaps and bounds, from the invention of mechanical clocks to space shuttles. Powerful artificial intelligence could blur the differences between humans and computers in the coming centuries, he said.
Powerful artificial intelligence could blur the differences between humans and computers in the coming centuries, Hoffecker said.
Stephen Hawking agrees with Hoffecker. Although It has taken homo sapiens several million years to evolve from the apes, the useful information in our DNA, has probably changed by only a few million bits. So the rate of biological evolution in humans, Stephen Hawking points out in his Life in the Universe lecture, is about a bit a year.
"By contrast," Hawking says, "there are about 50,000 new books published in the English language each year, containing of the order of a hundred billion bits of information. Of course, the great majority of this information is garbage, and no use to any form of life. But, even so, the rate at which useful information can be added is millions, if not billions, higher than with DNA."
This means Hawking says that we have entered a new phase of evolution. "At first, evolution proceeded by natural selection, from random mutations. This Darwinian phase, lasted about three and a half billion years, and produced us, beings who developed language, to exchange information."
But what distinguishes us from our cave man ancestors is the knowledge that we have accumulated over the last ten thousand years, and particularly, Hawking points out, over the last three hundred.
"I think it is legitimate to take a broader view, and include externally transmitted information, as well as DNA, in the evolution of the human race," Hawking said.
In the last ten thousand years the human species has been in what Hawking calls, "an external transmission phase," where the internal record of information, handed down to succeeding generations in DNA, has not changed significantly. "But the external record, in books, and other long lasting forms of storage," Hawking says, "has grown enormously. Some people would use the term, evolution, only for the internally transmitted genetic material, and would object to it being applied to information handed down externally. But I think that is too narrow a view. We are more than just our genes."
The time scale for evolution, in the external transmission period, has collapsed to about 50 years, or less.
Meanwhile, Hawking observes, our human brains "with which we process this information have evolved only on the Darwinian time scale, of hundreds of thousands of years. This is beginning to cause problems. In the 18th century, there was said to be a man who had read every book written. But nowadays, if you read one book a day, it would take you about 15,000 years to read through the books in a national Library. By which time, many more books would have been written."
But we are now entering a new phase, of what Hawking calls "self designed evolution," in which we will be able to change and improve our DNA. "At first," he continues "these changes will be confined to the repair of genetic defects, like cystic fibrosis, and muscular dystrophy. These are controlled by single genes, and so are fairly easy to identify, and correct. Other qualities, such as intelligence, are probably controlled by a large number of genes. It will be much more difficult to find them, and work out the relations between them. Nevertheless, I am sure that during the next century, people will discover how to modify both intelligence, and instincts like aggression."
If the human race manages to redesign itself, to reduce or eliminate the risk of self-destruction, we will probably reach out to the stars and colonize other planets. But this will be done, Hawking believes, with intelligent machines based on mechanical and electronic components, rather than macromolecules, which could eventually replace DNA based life, just as DNA may have replaced an earlier form of life.