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The Exceptional Brain and How It Changed the World
By Robert M Kaplan
Allen & UnwinCopyright © 2011 Robert M. Kaplan
All rights reserved.
I stand in the bright sunlight with closed eyes and face the sun. Then I move my outstreched, somewhat separated, fingers up and down in front of the eyes, so that they are alternately illuminated and shaded. In addition to the uniform yellow-red that one expects with closed eyes, there appear beautiful regular figures that are initially difficult to define but slowly become clearer. When we continue to move the fingers, the figure becomes more complex and fills the whole visual field.
It is 78,000 years ago. On the southern coast of Africa, a group of humans are in a cave alongside a series of rock ledges and reefs on the coastline. The sea (later to be known as the Indian Ocean) is bright blue. The rocks are covered with shellfish; as a wave withdraws, serried rows of shells, cysts, bladders and tubes spurt and squish and suck. Small fish swim in the gullies, octopi and crayfish scuttle under ledges or hide beneath swaying kelp. Seabirds hover and squawk, plunging whenever they see some item of food. Further out to sea there is the occasional spout of spume as a whale, looking for a suitable place to calve, comes to the surface.
The cave, which we now call Blombos, is spacious, tapering towards the back. The floor is covered with a carpet of shells, crunching underfoot, slowly pounded into a layer to record the presence of a generation, thousands of layers multiplying as the millennia pass. The inhabitants stand around or sprawl. They wear little aside from animal-skin loin cloths, the children scuttle around naked. One of the younger women, showing the first glow of pregnancy, is more ornately decorated. In her hair are several bone needles. Around her neck hangs a necklace made of twine from a local bush strung with rows of shells of the limpet crab, found in the lagoon. The shells, rubbing softly against her skin, have acquired a glowing patina that brings out the natural colours in the shells.
In the centre of the group, squatting on his heels, surrounded by a scattered pile of red ochre chips, is a man with a stone in his hand. The squatting man, whom we shall call Daidalos in honour of Daedalus, the skilled and cunning artificer of Greek mythology, is trying to explain to his audience what had happened to him the night before. Driven by an urge he could not understand, Daidalos left the cave and squatted on a rock outside that gave him a clear view of the skies. This was something he did frequently, fascinated by both the sparkling stars that appeared to resemble animal shapes and the trajectory of the moon across the inverted bowl of the sky. These inspections left him with a sense of contentment and he would always sleep well afterwards. But this night was different. The sky was unusually clear, the moon was full and, as he sat down and took up his position, a blazing comet shot across the sky before disappearing in a shower of sparks.
For several hours, Daidalos stared directly at the incandescent moon, occasionally shifting his position to adjust to its arc, blinking only when he could not keep his eyelids apart. Before long, he began to experience changes. His instinctive awareness of where he was and what was around him began to waver and flicker. He seemed to be plummeting or soaring; he could not say which; he felt he no longer owned his body. Then, to his shock, he realised that he was looking down at his body squatting on the rock. In his ears, there was a humming noise. The sense of whirling and tumbling increased, whatever concept he had of the present was lost and he felt he was being absorbed into the sky. The bright moon seemed to have receded and the patterns of the constellations drew closer, flickering, winking and sparkling. The stars coalesced to form regular patterns that he had never seen in the natural world. The patterns, which we call geometric, had precise and regular forms with rectangles, series of blocks like bricks in a wall, nested curves and circles, and a single diamond shape that expanded to a shimmering pattern, forming a crosshatched grid. At its apogee, several glowing spots shot across the grid like lines of unleashed energy.
Daidalos had little recall of what happened after that. Several hours later, before dawn, he found himself awake. He picked himself up off the rock and returned to the cave.
Now he wanted to tell his companions of his experience. But Daidalos lacked the verbal capacity. At that stage, humans still used a protolanguage, limited to doing not much more than naming items, accompanied by hand gestures, facial expression, grunts and other noises. None of this repertoire would assist him to describe an experience that was beyond anything he, or they, had encountered.
The group, of whom he was the natural leader, stared at him quizzically. At a loss, Daidalos looked around him. Among the pile of ochre chips, left from a recent exercise to prepare red body paint and mastic — used as a glue to attach small stone points to spear tips — were several larger lozenge-shaped ochre pieces. He picked up a little slab, indicating to the group with his free hand that he wanted to explain what he had seen the previous night. Suddenly, without quite realising what he was doing, with a pointed cutting stone tool in his right hand, the ochre slab in his left, he began to drag the point across the flat ochre surface, going back and forth. He stopped and looked at what he had created. Nodding his head, he inspected the little slab. On the surface, in a series of lacerations, was inscribed the geometric crosshatching pattern he had seen the previous night. He realised there was still something missing. In two firm swipes, he pulled the cutting tip across the pattern, etching in the energy lines that had exploded across his vision the night before.
Pleased, he held out the inscribed tablet to his audience who crowded around. What he had done was to create what may well have been one of the first graphic examples of symbolism, the critical feature of modern behaviour that separated the new humans from every species that had come before it. Tossed into the rubble, it was to lie undisturbed for another 78,000 years until a team of archaeologists brought it to the attention of the world.
The people in Blombos Cave were modern humans — Homo sapiens — who had the same anatomy as we do. They arose from what is known as the speciation event 195,000 years ago. From that point, with minor variations, humans have not changed anatomically. Early humans had the same brains we have and the capacity to demonstrate what we call modern behaviour. While they appear to have first arisen in the region of modern Ethiopia, they moved to the south of Africa. But they were never destined to stay in one place and the human adventure commenced 50,000 years ago; they began moving out through the narrow neck connecting Africa with the Levant, or across the Red Sea by the Arabian Peninsula, going on to colonise every environment on the planet.
Fast forward to the present. Excavations at Blombos Cave reveal a mass of artefacts going back as far as 130,000 years. The findings include incised bone tools, exquisitely facetted opal-shaped stone tools, many in shining silcrete which had to be obtained from a long distance away, and ochre shards used for decoration.
Two small inscribed ochre slabs caused a sensation. The careful dating (78,000 years) of the level in which the ochre slabs were found was incontestable and led to headlines around the world. Even the shapes were unusual, suggesting a deliberate intention to create some kind of panel, rather than being the off-cuts from grinding ochre for other uses. The geometric patterning was undoubtedly human. There was no evident way in which the inscriptions on the ochre could have occurred through natural processes, accident or any other means; they resulted from deliberate human intention and could only have been applied by people with well-developed eye — hand coordination in a hand adapted to precision-grip activities, such as manufacturing stone tools. Once the implications of the ochre inscriptions were absorbed, the Blombos investigators unveiled another revelation: a mollusc shell necklace, using limpet snail shells similar to those found in a nearby lagoon, the shells revealing a deliberate piercing to pass a string or hide cord through and showing signs of wear.
The unavoidable conclusion is that the artefacts indicate that the Blombos people were able to demonstrate what we call modern behaviour. The artefacts are the material indication of our capacity for symbolic behaviour, the basis of language.
The dating of the finds was a body blow to the prevailing view that the first modern human behaviour had occurred around 40,000 years ago in Europe during the transition from the middle to the upper Palaeolithic, suddenly appearing at the same time as the Neanderthals were replaced by modern humans. This resulted in subsistence farming and settlement, stone tools, organised hunting, reliance on blade technology and long-distance procurement of raw materials. The Eurocentric view of modern humans had been under assault for some time and, like all deeply held beliefs, was reluctantly, to say the least, surrendered by the establishment. It had become evident that modern behaviour had arisen far earlier at a number of scattered sites around Africa. Rather than being a 'revolution', this process occurred over long periods in different groups around the continent, who made small changes that slowly accumulated. The progress was not linear. Some groups did not survive; in which case, their innovations and developments were not passed on.
The most significant breach in the wall of denial arose in the last two decades with the findings at the Klasies River Caves, further east of Blombos along the same Indian Ocean coast. KR, as it became known, yielded a series of stone tools and related artefacts over a period of 60,000 years, showing the unmistakable presence of what is known as Middle Stone Age (MSA) tools going back as far as 115,000 years. MSA tools were a further development in stone tool technology. Their makers cut blades and cutters off a stone core, but more importantly, the tools' variation in size, shape and utility indicated the ability of the tool maker to think three-dimensionally, to plan ahead to flake the core, to show others how to repeat the process and, in all likelihood, to choose different ways of making tools.
The argument over what constitutes human modernity has raged for some time, but there is widespread agreement that at the heart of this concept is the capacity for symbolic behaviour — which can be summed up in one word: language. Language can express itself with the use of speech, the design of advanced stone tools requiring forethought and planning, and artistic or spiritual behaviour.
Pre-Blombos, the argument was slowly but surely shifting to acceptance of an African evolution, as opposed to a European 'revolution' around 40,000 years ago. To ram home the point, archaeologists have since found inscribed ochre at another site, Pinnacle Point, up the road from Blombos, dated to an incredible 164,000 years ago.
But the Blombos findings came first, and confounded everyone. In addition to the crosshatched ochres, there were over 8,000 used pieces of ochre plus the perforated shell beads used for personal ornaments. Stone tools are one thing; after all, there is evidence of the first use of stone tools by hominins in Ethiopia going back 2.6 million years, and the development of such technology, albeit in fits and starts, would have been intuitive. But the inscribed geometric symbols, as well as the use of shells for ornamentation, laid to rest the old paradigm. Post-Blombos, there was only one logical conclusion: fully modern people had evolved in southern Africa by 78,000 BCE and were demonstrating symbolic behaviour with ornaments and abstract designs.
We know that the Blombos humans had the anatomical capacity for language (brains with a speech centre and changes in the upper airway to permit vocalisation), but we have no other way of knowing how they spoke, only that they had the capacity for abstract thinking, the mental manifestation that results in symbolic activity.
So can we explain how the geometric grid patterns could have arisen? We cannot say for sure if they were produced in an altered state of consciousness, although this is a reasonable supposition. The images do not exist in nature. The only place from which they could arise was somewhere within the brain of the inscriber.
A possible explanation for the inscriptions comes from visual neurophysiology, long a matter of speculation but escalating into a science in the last century. Sensory deprivation can produce visual forms such as rows of dots, geometric patterns and mosaics. Flashes of light at certain frequencies produce hallucinations of intricate patterns and vivid colours. But the most detailed way to study geometric illusions and hallucinations is through the effects of hallucinogens.
As we have seen, Klüver described the geometric patterns that he hallucinated, dividing these into categories known as form constants. These included: tessellopsia (grid patterns construed by subjects as brickwork, lattices, netting, crazy paving, cobwebs and chequerboards); dendropsia (irregular branching forms described as maps, trees or branches); and polyopsia (reduplication of images, both geometric and iconic).
Visual hallucinations can occur in those with impaired vision, altered states of consciousness and pathological states (such as strokes, infections and macular degeneration). A migraine can also produce a hallucination, or scotoma, known as a 'fortification illusion': a luminous, jagged arc starts near the centre of the field of vision and expands until it passes beyond the periphery. Migraines can induce visions of latticed, faceted and tessellated motifs, as well as images reminiscent of mosaics, honeycombs, Turkish carpets or moiré patterns.
Geometric visual illusions are also experienced in hypnagogic states (perceptual changes occurring at the point of waking or falling asleep), hypoglycaemic coma or by looking at disks with rotating black, white or coloured sectors. Among the descriptions of hallucinations occuring at the sleep — wakefulness boundary are luminous wheels and whirling suns.
Our current knowledge of the origin of visual hallucinations comes from psychiatrist Dominic ffytch, who used the latest technology to show that the geometric patterns, occurring in a range of normal or pathological circumstances, arise from the structure of groups of cells in areas V1 and V2 of the occipital (visual) cortex. According to ffytch, reflecting these anatomical structures, visual hallucinations are located in the world around us, not in the mind's eye. They are not under our control, in the sense that we cannot bring them on or change them as they occur. They look real and vivid, although the things one sees may be bizarre and impossible.
In short, geometric visual phenomena are wired into the human brain, originating in the visual cortex. The anatomical structure of the cells determines the shapes, which are perceived as arising externally. The geometric grids etched on the Blombos ochres were in all likelihood form constants produced in trance states. We don't know how these states were produced, but we do know that one of the earliest modern humans, all that time ago in Blombos Cave alongside a sparkling African ocean, was inspired to scratch out what he saw on the soft stone surface, leaving an enduring and poignant reminder of our brain's first steps to take control of the world around it.
... the question we wish to answer is: What is it that determines the directions and turns of behavior? More specifically, what are the factors which impart certain directions to the animal's behavior in situations in which reactions to sensory stimuli are performed? What are, briefly speaking, the determinants of sensory responses? We are not interested in the fact that there is such a thing as 'behaviour'; we are interested in the factors responsible for certain kinds of behaviour.
Heinrich Klüver, one of the foremost psychologists of his time, had a significant influence on neuroscience. He is most famous for his experiments with the hallucinogenic drug peyote and surgery on monkeys, producing what became known as temporal lobe syndrome or Klüver-Bucy syndrome. His work highlighted for the first time the critical role of the brain's temporal lobes.
Klüver was born in Schleswig-Holstein, Germany, in 1897. After reluctantly serving as a private in the German Army, he studied psychology at the University of Berlin and the University of Hamburg. Disillusioned by the chaos and extremism of post-World War I Germany, in 1923 he travelled to the United States, where he stayed for the rest of his life.
After interludes at the University of Minnesota and Columbia University, Klüver moved to the University of Chicago where he worked up to the year before his death. There he was by far the brightest light in an unusually strong field of neuroscientists, including such luminaries as Karl Lashley, Percival Bailey, Stephen Polyak, Charles Herrick and Roy Grinker. Famously reticent, Klüver avoided all administrative and teaching duties and would only allow certain approved visitors beyond the locked door into the inner sanctum of his laboratory.
Excerpted from The Exceptional Brain and How It Changed the World by Robert M Kaplan. Copyright © 2011 Robert M. Kaplan. Excerpted by permission of Allen & Unwin.
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