lunes, 26 de septiembre de 2011
Did Our Human "Super Brain" Suddenly Appear 75,000 Years Ago?
There is mounting 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 Hoffecher, an archaeologist at the University of Colorado.
While the concept of a human super-brain is analogous to social insects like bees and ants, which 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.”
While crude stone tools crafted by human ancestors beginning about 2.5 million years ago likely were an indirect consequence of bipedalism (walking upright) -- 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.
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,” Hoffecker said.
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, 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.
Stephen-hawking 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.
Source: The Daily Galaxy