The Rise of Homo Sapiens



The Rise of Homo Sapiens, by Frederick Coolidge (psychologist) and Thomas Wynn (anthropologist), is a book about the evolution of human cognition.  It describes the seven million year voyage that resulted in the magnificent mind that’s throbbing between your ears right now.  This voyage began with the first hominins — bipedal (two legged) apes who were either our direct ancestors, or our long lost cousins.

Note that the details of human evolution are the cause of endless barroom brawls among rowdy paleoanthropologists and archaeologists.  They constantly argue about the members of our family tree, the transitions between one species and the next, and the dates when changes happened.  To keep it simple here, the first brainy hominin was Homo erectus, who arrived on the African stage 1.8 million years ago.  Erectus probably evolved into Homo heidelbergensis, who was maybe the common ancestor of both Homo neanderthalensis and Homo sapiens (our hero!).  Neanderthals are our cousins, not our direct ancestors (we share at least 99.5 percent of our DNA).

The authors believe that there were two significant surges in cognition, (1) Homo erectus 1.5 million years ago, and (2) Homo sapiens 40,000 years ago.  Erectus had a large brain, knapped stone tools, and was the first to move beyond woodland habitats.  They were able to survive in everything from dry savannahs to tropical rainforests.  From Africa, they spread to southern Europe and much of Asia.  Around 1.5 million years ago, they invented a major advance in stone tools — biface knapping.  These were hand axes and cleavers that had two cutting edges.  For the first time, folks could now effectively butcher large animals — an ability that greatly expanded their food resources.

Razor sharp stone tools were revolutionary.  Great apes, monkeys, and other mammals can only cut and chop with their teeth.  This book made me appreciate, for the first time, the huge importance of stone tools.  Cutting is big juju!  Imagine a world in which teeth were the only cutting edges for any purpose.  Civilization would be impossible, and you and I would be naked wild things on a sunny African savannah.

Another revolutionary technological discovery was the domestication of fire, which kicked open the gate to life as we know it.  The earliest evidence of fire was found in an African cave, dating to 1.4 million years ago.  Erectus was probably a fire user.  Prior to manufactured tools and domesticated fire, our ancestors were still ordinary animals, like baboons — wild, free, and happy.  These two changes shoved them outside the community of all other animals, and put them on an ominous new path.

In the million years following the invention of biface cutters, Homo erectus artifacts reveal no evidence of further innovation.  Maybe they now had everything they needed, and life was grand.  But the book’s authors live in a culture that is constantly disrupted by hurricanes of innovation.  To them, a million years of stability and sustainability is glaring evidence of feeblemindedness. 

Both authors are shameless out-of-the-closet human supremacists, and their book is a flag-waving celebration of human brilliance.  They write, “Homo sapiens has transformed the natural world into one of culture and civilization that our distant ancestors, let alone members of other species, possibly could not imagine.”  No kidding! 

The authors are also masters at the mysterious art of academic writing.  Behold: “The allometric trajectory that best distinguished anatomically modern Homo sapiens and Neanderthals was a tendency towards klinorhynchy or globularity in modern humans.”  The book was not a pleasure read for a general reader like me.  I was not the intended audience.

In the book, hominins are essentially presented as being biological machines.  Much attention is devoted to brain size, brain components, brain processes, and genetic evolution.  Subjects include decision making, planning, memory, learning, abstract thinking, language, communication.  Bones and artifacts reveal little or nothing about stuff like thinking, memory, or speaking, so the book indulges in a lot of speculating, which could get quite frisky, sometimes hopping over the fence of credibility.

Homo sapiens maybe emerged around 200,000 years ago.  Somewhere around 30,000 to 40,000 years ago, there is evidence of a significant shift that is often referred to as the Great Leap Forward.  It was an era of breathtaking cave paintings, decorative ornaments, ceramics, carvings, and innovation in hunting technology.  The authors make the highly controversial assertion that this big shift “developed because of an additive genetic mutation or epigenetic event that affected the neural organization of the brain.”  And so, a new and turbulent chapter in the human saga was the result of random genetic juju that scrambled our thinkers.

Far less attention is devoted to significant factors that were external to the brain machines and their magic genes.  By the time of the Great Leap, folks had struggled to overcome a number of major challenges.  They had figured out how to survive in a chilly temperate climate — warm clothing, secure shelters, food storage.  Utilizing the latest state of the art technology, they had become highly skilled at team hunting.  They lived in regions having abundant game.  People who are struggling to survive are not going to have time to fool around with nonessential amusements.  But people living in times of prosperity, like the Baby Boomers, or the cave painters, can indulge in fanciful excesses and extravagances.

In the Great Leap era, the world was unimaginably alive and a spectacular, breathtaking miracle.  Modern folks would eagerly pay big money, and get on a 40-year waiting list to experience a pure, thriving wilderness filled with mammoths, lions, aurochs, and buffalo.  To gasp with wonder at vast clouds of birds filling the skies with beautiful music and motion.  To listen to rivers thrashing with countless salmon.  To see, hear, and feel the powerful vitality of the reality in which our species evolved, the type of world that the genes of every newborn baby expects to inhabit — a healthy, sane, beautiful, wild paradise.

Craig Dilworth wrote that the cave painting tribes were the luckiest humans of all, because they lived at the zenith of the entire human experience.  A number of revolutionary innovations had provided them with a temporary opportunity to experience a magnificent way of life.  But the road ahead was a rough one.  Another ice age was approaching, and Europe would get colder than it had been in 100,000 years.  Large game would become less abundant due to habitat change, and to the long-term consequences of, century after century, killing a few too many big critters that did not breed like bunnies.

Technological innovation has a regular habit of sharply biting its clever inventors, and their societies, on the ass.  Patching up the damage caused by the unintended consequences of progress typically inspires even more innovation, leading to even more unintended consequences, resulting in a treacherous downward spiral. 

Humans have retained some characteristics of ordinary animals — our minds are focused on the here and now, our capacity for acute foresight is flaccid, and we often become prisoners of habitual thoughts and behaviors.  Over time, human numbers grew, and food resources diminished.  Storms of devastating cleverness eventually led to the domestication of plants and animals, a transition that many anthropologists refer to as the Great Leap Backward. 

And now, dear reader, here we are, standing in the growing shadow of an era of climate change helter-skelter, a painful withdrawal from a total addiction to energy guzzling, and the eventual obliteration of life as we know it.  And, here we are talking about a book that celebrates the miracle of human cognition.  Oy!

A year ago, I spent a few hours with this book, and set it aside.  Recently, I looked at it again, because I was interested in some anthropological information.  I contemplated reviewing it, but decided not to.  Then, my muse gave me a dope slap (SMACK!).  The book is perfect!  It’s a haunting mug shot of the mindset that is engaged in a full-scale war against all life — yet refuses to notice it, or care.

This is the mindset in which educated brains are thoroughly marinated from childhood onward.  Like standing in front of a curvy funhouse mirror, the distorted reflection we see is Superman or Superwoman, powerful beings of greatness and goodness.  Thus, the notion of superheroes knowingly engaging in pathological mass destruction is perfectly ridiculous.  We much prefer the flattering portrait to the lost and confused critter behind the mask.  This may not be the path to a happy ending.

One passage noted that, “excepting humans,” today’s great apes are in decline (chimps, bonobos, gorillas, orangutans).  Could their big brains have doomed them?  “Large brains are expensive and have profound life-history consequences.  If they no longer yield a competitive edge, their owners will, predictably, go extinct.”  Do you think that humans truly are the exception?  Is our ever-growing cleverness rotting out our competitive edge, as it undermines the ecosystems that make our existence possible?  Will our superhero brains ever snap out of their trance, open their eyes, and become fully present in reality?  Stay tuned.  And now, a message from our sponsor…

Coolidge, Frederick L., and Thomas Wynn, The Rise of Homo Sapiens: The Evolution of Modern Thinking, Wiley-Blackwell, Chichester, U.K., 2009.

Lone Survivors

A million years ago, our Homo erectus ancestors consisted of maybe 20,000 breeding individuals, according to wizards who speculate on the hidden secrets of DNA.  This is similar to the current population of chimpanzees or gorillas.  The ancestors lived in scattered pockets of Africa, at a time when Earth was a paradise of abundant life.  From these ancient roots, a number of hominid species evolved, but only Homo sapiens still survives, at seven-point-something billion and growing.  The chimps and gorillas continue to live in a manner similar to their ancestors of a million years ago.  What happened to us?

Chris Stringer is one of the venerable grandfathers in the study of human evolution.  He’s read the papers, attended the conferences, examined the skulls, and had a ringside seat at the noisy catfights.  This field of knowledge is far from finished.  New specimens continue to be found, and new technology provides deeper insights.  Stringer’s book, Lone Survivors, discusses some primary issues, and the scholarly disputes surrounding them, as they stood in 2012.  He does a pretty good job of providing an overview to a huge and complex subject, but readers with little background are advised to wear life preservers.

I learned a lot about Neanderthals.  They survived 400,000 years on a climate change roller coaster.  They hung out with hippos in warm forests near Rome, and they chased wooly mammoths on frigid treeless tundras.  They had short, stocky bodies that were good for preserving heat, but which required more calories.  Males and females were about the same size, suggesting little division of labor, everyone joined in the hunt. 

The Neanderthal diet majored in the flesh of large game.  Readers who have hunted hippos with wooden thrusting spears know that his is very dangerous.  One site in Croatia contained the remains of 75 Neanderthals, and none were older than 35.  In their clans, there were probably many orphans and few grandparents.  The scarcity of elders, and the small size of their groups, sharply restricted the flow of cultural information from one generation to the next, and from clan to clan.

Some say that Neanderthals lacked shoes and close-fitting clothing.  When Darwin visited chilly Tierra del Fuego, at the bottom of South America, he was shocked to see natives wearing little or no clothing and sleeping naked in the open.  Stringer noted that modern Europeans seem to be poorly adapted to the cold, physiologically.

Cro-Magnons were the Homo sapiens that moved into Europe maybe 45,000 years ago.  European Neanderthals disappeared around 30,000 years ago.  Neanderthals went extinct in the Middle East, Siberia, Gibraltar, and Britain at different times, probably for different reasons.  This was an era of frequent climate zigzags.  When temperatures plummeted, habitable territories shrank, and fewer folks could be fed.

Cro-Magnons apparently had footwear and warm, fitted clothing.  They had better tools for hunting, so their diet was more diverse and dependable.  They were able to extract more nutrients from an ecosystem, so they could survive in places where Neanderthals could not.  They lived in larger groups, and more of them survived to middle age or old age, so more cultural information could be passed to the young.

Large populations are better at preserving cultural knowledge, acquiring new information from outsiders, and generating innovations.  More busy minds interact, exchange ideas, compete, and imagine cool ways for living even farther out of balance.  Witness the city of Los Angeles, where 14 million animals with hunter-gatherer DNA are temporarily able to survive because of a highly complex system of innovative technology.  Note that this innovation has no relationship to foresight or wisdom.  Time is running out on Los Angeles.

On the other hand, less innovation occurs in smaller simpler groups, and that’s often a blessing.  Innovators can be dangerous loose cannons, introducing risky new ideas that result in horrid unintended consequences — like cell phones, automobiles, or agriculture.  Nothing is more precious than a stable, sustainable, time-proven way of living, where the secret to success is simply imitating your ancestors, conforming to the norm, and enjoying life, like the chimps and gorillas do.

When the planet heated up 14,000 years ago, rising sea levels submerged the land link between Australia and Tasmania, terminating the exchange of people, ideas, and gadgets.  Tasmania’s traditional way of life was also squeezed as the warmer climate spurred the expansion of heavy forest.  The natives experienced a cultural meltdown.  “Tasmanians appear to have led an increasingly simplified life, forgoing apparently valuable skills and technologies, such as bone and hafted tools, nets and spears used to catch fish and small game, spear throwers and boomerangs, and anything but the simplest of skin clothing.”

Will climate change have a similar effect on industrial civilization in the coming decades?  Will it slash food production, sharply reduce population, eliminate travel between regions, pull the plug on modern technology, and erase lots of obsolete and unsustainable cultural information?  Could collapse have a silver lining?

Climate change can derail any culture, and drive species to extinction.  It can also produce beneficial conditions, like the unusually favorable climate of the last 10,000 years.  Natural selection rewards species that can adapt to change, and it deletes those that fail.  There is another important variable that is often overlooked — genetic drift — mutations that happen all the time when slight boo-boos occur during cell division.  These tiny defects can provide a barrel of surprises.

We are repeatedly taught that humans are nature’s flawless masterpiece, the glorious conclusion of three billion years of evolution.  But, if Big Mama Nature had experienced slightly different moods over the eons, we might be Neanderthals or Denisovans today (or maybe slime mold).  Climate change and genetic drift are purely random.  The fact that Homo sapiens is the lone survivor among the hominid species is not absolute proof of superiority, but it does indicate a temporary streak of good luck.

Homo heidelbergensis was an ancestor that lived 500,000 years ago.  They had brains ranging in size from 1100 to 1400 cc (modern brains average 1350 cc).  The average Neanderthal brain was 1600 cc — much bigger than ours.  Stringer noted that our brains today are ten percent smaller than our Homo sapiens ancestors of 20,000 years ago.  Is there a message here?

Without words, chimps and gorillas can express contentment, affection, irritation, excitement.  But without complex language, they are more trapped within themselves.  Language took us “into new and shared worlds that were unknown to our ancestors.”  We can talk about the here and now, the past, the future, abstract concepts, feelings, imaginary worlds, and so on.

Later, innovative geniuses invented the use of symbols.  Now we can convert words into patterns of squiggly lines, for example: “computer.”  Writing enables us to communicate with folks in faraway places.  I can read words written by Julius Caesar, and so might the generations yet-to-be-born, in theory.  Industrial civilization cannot exist without symbols — numbers, graphs, pictures, status symbols.  Progress abounds with powerful and dangerous juju.

Stringer is a mild mannered humanist.  And so, he portrays the human journey as one of admirable advancement (the chimps fall down laughing).  On the last page, he confesses a profound doubt.  “Sometimes the difference between failure and success in evolution is a narrow one, and we are certainly on a knife edge now as we confront an overpopulated planet and the prospect of global climate change on a scale that humans have never faced before.  Let’s hope our species is up to the challenge.” 

Stringer, Chris, Lone Survivors: How We Came to Be the Only Humans on Earth, Times Books, New York, 2012.