Trying to decipher how and why language developed is difficult because there is little evolutionary and developmental information included in the fossil record with which to build a credible theory. Written records start some 7000 years ago1 while language probably emerged in Africa some 100,000 years ago. This figure is based on language studies concerning the spreading-out of certain language attributes (phonemic diversity) that are then reversed to estimate a source point.2 The earliest anatomically modern humans are from around 195,000 years ago (The Omo remains) discovered in Ethiopia.3
There are nevertheless a few concrete developmental facts known about language. One is that language, the human brain, and the brain’s evolution are linked.
There is evidence that the ability to formulate language resides in the left side of the brain and not the right. We know this from attempts to treat intractable epilepsy.
The human brain is divided into two halves: a left hemisphere and a right hemisphere. If one slices an orange down the center so that only a small piece at the bottom holds the two pieces together, this is what the human brain looks like. The small piece that connects the two halves is called the corpus callosum.
Cutting the corpus callosum so the two halves of the brain have no connection is a surgical means of treating severe epilepsy when medications do not work. The procedure prevents electrical activity from flashing from one hemisphere to the other reducing the severity of the seizures. An unintended consequence of this surgery has been the opportunity to study how the left side differs from the right.4 Roger Sperry won the Nobel Prize for Physiology and Medicine in 1981 for his discoveries of the functional specialization of each side by studying so called “split brain” patients.
The two hemispheres operate independently and appear to have different characteristics and functions. The right is good at space, perception, and music while the left is good at analysis and verbal tasks.5
One peculiarity of our brains is that the right side of the brain does not control the right side, nor does the left side control the left. There is a cross over mechanism such that the left brain hemisphere controls the right side of the body and the right brain hemisphere controls the left.
Individuals that have no connection between their two hemispheres are only able to name and verbalize about unseen objects placed in the right hand because this is the side controlled by the left brain hemisphere. They are unable to verbalize about unseen objects if they are placed and held in their left hand.6 Therefore, it is the left hemisphere, the analytical side, which controls language and houses our language facility.
Not only does the analytical left side specialize in language but also with critical thinking, logic, schedules, specifics, and the self. The right side of the brain is more concerned with intuition, perception and the outside world.
Having separate brain hemispheres is not unique to humans.
All mammals have two hemispheres, but only humans have ones so comparatively large. Compared to those of a chimpanzee, human cerebral hemispheres are three times larger.
As to why they are bigger and more developed than other mammals, and why only one side has a language facility, we do not know.
An intriguing theory about the need and development of both hemispheres and their importance in human evolution comes from the hunting technique of modern day Hunter-gatherers inhabiting African savannahs like the Kalahari Desert in South Africa.7
We do know that grasslands and savannahs began to be established some 10 million years ago along with major diversification in grassland mammals and insects. The first hominine appears around 3 million years later. Brain size had been increasing in a linear fashion throughout the animal kingdom until between 4 million and 2 million years ago when the brain size in hominids tripled culminating in the appearance of the first homo species.8What spurred this acceleration, and why would nature select so heavily for increased brain size?
Persistence hunting is a method used by early humans and likely pre-humans to run other mammals to death by forcing them to succumb to heat stroke and exhaustion. This requires the ability to run long distances during the hottest part of the day, a skill the hairless upright human body is remarkably adept at doing. Humans sweat and shed most of their heat buildup in the process. Most other mammals have limited ability to shed heat and are prone to succumb if forced to exert themselves for extended periods of time particularly during periods of high temperature.9
Natural selection is about survival. It is about eating and being eaten. Humans have become the planet’s top predator, yet they are not built for speed and do not have huge teeth and claws. Instead, they are built for endurance, and they have a large brain that has two separately functioning halves. These characteristics have little to do with directly fleeing or chasing prey, but may have everything to do with tracking, organization, and intuition.
In the evolutionary arms race between the predator and the hunted, there have been many advances by both parties starting with the prey’s ability to flee. At some point hoofed mammals, such as antelope and buffalo, could no longer simply outrun a predator. In defense, the prey evolved uniform appearance and the herding instinct.
To bring down an antelope, a predator must concentrate on a single intended victim and then run it down despite the prey’s twists and turns. Numerous films of lions and cheetahs attacking wildebeests and antelopes show that they pick out a potential prey and zone out everything else. But with many creatures looking the same, there is a high probability the individual will get lost in the crowd and the attacker will lose focus on its intended target. A single lion has a success rate of only 15%. This figure does not change until at least six lions hunt together and even they are only successful 32% of the time.10
Enter onto the scene a predator that had the ability to pick its intended victim out of the herd and keep after it, thinking like it, being it, tracking it no matter how it tried to blend in and disappear in the sea of other animals. The prey could easily outrun the hunter. It could streak ahead and disappear from view, circle back, and mingle with the herd again all to no avail. The predator would pick it out and run it down.
For this to occur, the new predator had to be able to think like the prey while being the predator. This in effect required two sets of thinking mechanisms. One part was analytic. It examined tracks, communicated with others, worked out the strategy of who in the hunting party would press forward, and who would take their place when they tired. The other part thought like the prey transporting itself into the mind of the hunted. If one got inside the head of the prey, one would not lose the particular animal in a crowd even if it had ranged ahead out of sight. This was intuition and profiling put to use simultaneously, both of which are right hemisphere strengths.
Self-awareness may have been a consequence of this form of hunting. By getting inside the mind of the prey, one would know one was being hunted and by whom.
In modern times, it is difficult to image a world without communication and language and not being plugged into events happening all over the world.
In 2001 two conservationists, Leanne Allison and Karsten Heuer, tracked the Porcupine caribou herd for over a thousand miles through the Arctic National Wildlife Refuge. It took them weeks to rid themselves of their need for electronic contact with others. They suffered withdrawal symptoms before they could hike and search for the caribou in mental and physical silence. Eventually their right brain hemisphere characteristics became more apparent and useful while their language oriented left side became less dominant.
Karsten writes in his diary:
“…We are new at this, this following of intuition, and while pitching camp we second guess whether it is right or wrong. After so long (we) wonder why we sit instead of walk?”11
In their search, their intuition had told them to sit and wait and they found themselves following it. They were rewarded when as if by magic out of the fog walked hundreds of caribou.
A few days later he wrote:
“There have been too many coincidences over the last four months, too many signs appearing at just the right moment to attribute everything to luck. There are so many places in this vast assemblage of mountains, valleys and coastal plains where there aren’t any caribou, yet day after day, we stumble on to them, or them onto us…”12
Persistence hunting still takes place in remote locations of the world. The success rate according to Louis Liebenberg, who first recorded persistence hunting in 1985 and accompanied four hunters in the Kalahari, was as high as 80%.
By running the prey to death one needs nothing but a sharpened flint to prepare the meal. No other tools are needed: no bow and arrow, no spear. As a bonus, no blood is spilt that may attract other predators such as lions and hyenas, nor is there any likelihood of bodily damage from flailing hoofs and horns.13
How long it took for this type of behavior to manifest is unclear. Judging from the results, persistence hunting was more successful when compared with other predators. What was needed was highly developed left brains to organize along with a highly developed right brains so no prey could escape.
As temperatures rose due to early climate change, this hunting would have been more successful and with the added bonus of providing a concentrated high protein diet to stimulate growth.
However, nature selects not when life is easy, but when resources are scarce or the species is under environmental stress. If there was a period of rapid climate change from hot to cold and back again several times, only those with the highest abilities could possibly survive and accelerated growth of such attributes through natural selection would occur.
With self-awareness, a successful method of survival, and the achievement of being the top predator, why would there even be a particular need for language and the left side of the brain to develop in such an environment?
Perhaps, because humans were so successful; after all, what does the top predator have to fear but others of the same species?
Suppose one’s mate and two children are sitting by the fire and three strangers appear. What is to prevent your mate being taken from you, your two children killed, and your mate forced to create another family with the aggressors provided she still could?
In terms of numbers in this example there were originally seven humans. After the encounter there are four with several years before the number is back to seven and, what is to prevent the same cycle from recurring over and over?
If this were the case human population numbers would plummet with extinction likely as not.
On the other hand, what if one could tell stories, create empathy, and communicate a commonality? Those that could would likely be able to survive such an encounter and thereby be able to pass on their communication and left brain skills. This group and its offspring would become widespread and predominant forming the basis for the leap into language.
In that case language was never about hunting or finding food. Chances are this was happening well before language ever arose. Language development was about surviving encounters with others of the same species, something that has proven essential even today.
- Durant, W. (1963). Our Oriental Heritage. New York, NY: Simon and Schuster
- Wade, N. (2011, April 14) Phonetic Clues Hint Language is African-Born. The New York Times. Retrieved February 14, 2013 from http://www.nytimes.com/2011/04/15/science/15language.html?_r=0
- Mayell, Hillary (2005, February 16). Oldest Human Fossils Identified. National Geographic News. Retrieved February 14, 2013 from http://news.nationalgeographic.com/news/2005/02/0216_050216_omo.html
- O’Shea, M. (2005). The Brain, A Very Short Introduction. New York, NY: Oxford University Press
- “The Split Brain Experiments”. Nobelprize.org. Retrieved February 15, 2013 from http://www.nobelprize.org/educational/medicine/split-brain/background.html
- O’Shea, op. cit.
- McDougall, C. (2009). Born To Run, A Hidden Tribe, Superathletes, and the Greatest Race the World Has Never Seen. New York, NY: Alfred A. Knopf
- Christian D. (2008). Big History: The Big Bang, Life on Earth, and the Rise of Humanity. Chantilly, VA: The Teaching Company
- Liebenberg, L. (2006, December) Persistence Hunting by Modern Hunter-Gatherers, Current Anthropology, Vol 47, Number 6. Retrieved on February 15, 2013 from http://www.mattmetzgar.com/wp-content/uploads/2007/08/persistence_hunting.pdf
- Myhrvold, N. (2007). Lions: Africa’s Magnificent Predators. Edge: The Third Culture. Retrieved February 15, 2013 from http://www.edge.org/3rd_culture/myhrvold_lions07/myhrvold_lions07_index.html
- Heuer, K. (2005) Being Caribou, Five Months on Foot with an Arctic Herd. Minneapolis, MN: Milkweed Editions p. 187
- Heuer, op. cit., p. 205
- Liebenberg, op.cit.
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