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Monday, December 5, 2022
Dr. Brown: The great transition when humans became fully human

The story of human origins is very much a work in progress, mostly for want of fossils and artifacts to fill in remaining gaps in the record.

But as matters stand, the story began between five and seven million years ago with apes, which were bipedal at least part of the time.

Then after a gap in the record of one to two million years, there appeared a flurry of small-brained bipedal apes whose reign lasted three million years. Toward the end, they overlapped with a few transitional species and the appearance of homo erectus, the first of a family of fully upright, bigger-brained, more dextrous species – which ultimately led to modern humans and our cousins, the neanderthals and denisovans.

Throughout erectus’s term of almost two million years, the brain doubled in volume to eventually reach the lower limit for modern humans in specimens from Java and China. Despite the larger brain there’s little evidence that erectus refined his principle tool, the hafted ax, nor did erectus leave any evidence of what we would recognize as cultural objects.

On the plus side, erectus managed to control fire and thus provide a steady brain-friendly diet of cooked meat rich in vitamins, minerals, carbohydrates, fats and protein – just what was needed to support energy-hungry big brains.

But human evolution wasn’t all about acquiring a suite of fully modern musculoskeletal traits – a globular cranium with a prominent forehead, flatter face, smaller jaw and teeth and lighter framed and less muscular bodies compared to our cousin species, the neanderthals.

For none of those modern traits would have forecast the explosive behavioural revolution of humans about 100,000 years ago or perhaps as early as 200,000 years ago, about the time when the earliest anatomically modern humans walked the Earth.

What transformed modern humans had much more to do with the acquisition of a suite of behavioural traits, each compounding the effects of the others. And what were those changes?

Modern humans and possibly neanderthals, possessed a brain capable of nuanced symbolic thinking and language. The latter offered a quantum leap forward in their capacity to share thoughts, feelings, intentions, understandings, memories and speculations about the future with others on a scale far surpassing that of any predecessor species and other highly intelligent animals, such as chimpanzees, whales and elephants.

Symbolic thinking and language coupled with a vivid imagination undoubtedly led to storytelling and, especially, creation stories.

Based on the stories of the few hunter-gatherer societies that survived into the 19th and 20th centuries, those stories would have included accounts of the group’s origins and ancestors. There also would be tales of triumphs and disasters, relationships with the primal forces of nature, the animals, predators and game alike with which they were so familiar. And taking it a step further – creating hybrid creatures – half-human and half-animal statues such as lion man and a lively animated spirit world as vivid and as real to them as the actual world they inhabited.

Those stories, perhaps recounted by a respected elder or shaman, would have provided common bonds and social rules for a community and a framework for making sense of what was often a frightening and dangerous worldscape. Those stories and the minds behind them, no doubt played a major part in the creation of so much of the magnificent cave art throughout Europe, Asia, Australia and the Americas.

Most paleolithic societies, whether in Africa, Eurasia or Australia, were small – with perhaps 50 to 150 members of extended families – who, as Australian studies reveal, met annually with other like groups who shared their common language and beliefs, to exchange goods, knowledge, skills and mates and strengthen alliances.

The last two must have been very important as sources of protection and food in a world where small groups were especially vulnerable to the vagaries of weather, food supply and threats from roving hostile bands. Altogether over many thousands of years, there must have been as many creation stories as groups, only the tiniest fraction of which have survived into the modern era.

Symbolic language, oral to begin with, and in the last 5,000 to 6,000 years, written language, conferred the ability to rachet knowledge forward by locking in what’s been learned and vetted in the past and adding to the common body of knowledge with each successive generation.

That was the great information multiplier for our species and like no other achievement by any other species. And the multiplier effect only grew, especially in the last century with the advent of the digital computer and soon, the quantum computer.

These days information that was in the past locked up in the archives of private or university libraries is now often but a click away. The information revolution was and is a human cultural revolution, not a biological revolution, although the opportunistic nature of the evolution of information is surely adaptive in nature.

The information revolution and the enabling symbolic language are why we are the “lone survivors” as Chris Stringer so likened us in his 2012 book by the same title (a favourite of mine). Thus enabled, modern humans outwitted and outlasted all other hominin species.

But as powerful as information can be for good, it has the potential to be destructive as when what’s true and trustworthy becomes overwhelmed by misleading and false information – as recent history reminds us.

Something to think about.