Survivorship Bias and Ancient Humans

Survivorship Bias and Ancient Humans

Yuval Noah Harari writes almost romantically about ancient human foragers in his book Sapiens. Describing the difference in knowledge, skills, and abilities between modern humans and ancient hunter-gatherers, Harari is absolutely glowing in his descriptions of ancient humans. He praises them for the knowledge, self-awareness, and connectedness between their bodies and the natural world. Something he argues modern humans have lost.
He writes, “Foragers mastered not only the surrounding world of animals, plants and objects, but also the internal world of their own bodies and senses. They listened to the slightest movement in the grass to learn whether a snake might be lurking there. They carefully observed the foliage of trees in order to discover fruits, beehives, and bird nests. They moved with a minimum of effort and noise, and knew how to sit, walk, and run in the most agile and efficient manner. Varied and constant use of their bodies made them as fit as marathon runners.”
I think this paragraph is generally accurate, if a bit hyperbolic, but troublingly, I think this paragraph is also subject to survivor bias. The humans who lived and survived the longest in a dangerous wilderness environment were probably as fit as modern day triathletes. They probably were more aware of seasonal changes and small details in nature that helped them find food and avoid predators. But I don’t see why we would extend those traits to all foragers. It is unlikely that every human was great at all of the skills Harari lays out, and it seems to me that it would be unlikely for all of them to be agile, fit, super proto-homo sapiens. Many probably fell short in a few areas, and if they fell too short in too many areas, then they probably died, leaving us with the survivorship bias that Harari ends up with. Ultimately, this gives us an overly-romanticized perspective of foraging humans.
Evolution Beyond the Genome

Evolution Beyond the Genome

I recently wrote about a quote from Yuval Noah Harari’s book Sapiens in which Harari argued that humans jumped up the food chain so quickly that we never psychologically adapted to becoming the most dominant species on the planet. An important aspect of this assertion is how humans were able to make the jump up the food chain. Evolution is a slow process, typically driven by genetic and epigenetic changes to the genome that take a long time to prove useful for survival and spread throughout a population. So how did humans evolve so quickly?
The answer, according to Harari, is that homo sapiens didn’t wait around for genetic changes. The species evolved outside of our genes, with the help of our brains. Sapiens began to cooperate in large numbers, and that changed how sapiens related to the rest of the planet. “the way people cooperate can be altered by changing the myths – by telling different stories.” The Cognitive Revolution and the increasing power of the human brain allowed ancient humans to first change relationships and interactions among themselves, which then changed how they existed in the world more broadly.
I think this can be seen in the way humans have organized themselves politically. A certain amount can be achieved and done when living in small tribes dominated by a single patriarch. More can be done within an autocracy, where a single powerful ruler has managed to bring all the small patriarchal tribes under unified control. And humanity has demonstrated that even more can be achieved through representative democracies. Changing myths allows for changing political organizations and structures, which changes the way people interact with each other and the world.
Harari continues, “Speeding down this fast lane, Homo sapiens soon far outstripped all other human and animal species in its ability to cooperate.” Our myths unlocked new potentials and created an evolution beyond the genome for our species. We didn’t have to wait for small genetic changes. We created social systems and structures for coordination and cooperation based on myths, and those changes supercharged our evolution and competition among other species of the planet.
The Most Durable Human Species Ever

The Most Durable Human Species Ever

In recent years our DNA sequencing techniques and abilities have become dramatically better. We are able to get DNA from ancient sources in a way that we previously had not been able to, and we are then able to sequence that DNA more accurately are carefully than ever before. What this has started to reveal is a greater diversity of ancient human species, a greater spread of various human species, and more diversity and intermixing of human species than we had previously thought. A lot of this research is cutting edge and evolving daily, but for the last decade this research has been shifting how we view ancient humans, which in turn shifts the way we view ourselves.
In Sapiens, published in 2011, Yuval Noah Harari writes, “the more eastern regions of Asia were populated by Homo erectus, ‘Upright Man’, who survived there for close to 2 million years, making it the most durable human species ever.” It is somewhat strange to think that one species of human existed for 2 million years, or close to that figure, and eventually was outcompeted by a different species of human. Homo sapiens, our modern human species, eventually outcompeted all the other species of humans, including those which existed for hundreds of thousands to millions of years before our species evolved and began to spread.
Since Harari’s book was published we have learned more about species he briefly mentions such as Homo denisova and how widely those species managed to spread across the Earth. Additionally, research during the COVID-19 Pandemic suggested that some individuals may have genetic mutations stemming from the genome of Homo neanderthalensis, which changed their immune response to the disease. To me, research on ancient humans through DNA is a powerful and humbling reminder that my life and experiences are not unique just to me and this moment. It reminds me that human evolution has been a long and complicated process, with many Homo Sapiens and other human species that could think, talk, and experience the world in similar ways coming before me. Harari also stresses that Homo Sapiens may not be the final version of humans to evolve and dominate the planet, or last the longest on the planet. He continues, “this record [the estimated 2 million years that Homo erectus survived] is unlikely to be broken even by our own species. It is doubtful whether Homo sapiens will still be around a thousand years from now, so 2 million years is really out of our league.”

Preservation of Our Environment

Taking care of our shared spaces and maintaining our environment is not something we do a great job of. Fields, rivers, lakes, and outdoor areas are everyone’s shared responsibility, and because of that, they are no one’s individual responsibility. We will maintain our own lawns or pay people to do our home landscaping, but when it comes to our public outdoor spaces, we often fail to maintain and preserve the land we share. These spaces are expensive to maintain, the threats of invasive species are hard to understand, and it is not clear who should be the person that spends the time and energy taking care of our public places. In political science this dilemma is known as the Tragedy of the Commons, and Cory Booker addresses it in his book United.

 

Booker writes, “We are all dependent on nature, so we all have a stake in the preservation of our environment.” Taking care of our planet is important because it is the only one we have, and it is what sustains our individual lives, our societies, and the only life we know of in the universe. At the same time, taking care of the planet is unclear with ecosystems connected and dependent on each other in complex ways, with connections we are not always able to understand. Scientific research is expanding, but still not at a point where perfect models of natural processes such as rainfall, erosion, or phosphorous cycling are possible. But we depend on what we know about nature, and must continue to push forward and be cautious with how we use nature so that we can maintain what we have for not just our generation’s use, but for the use of future generations.

 

The truth is that we must use nature. We need to extract minerals, metals, and plant based materials from the earth. The physical structures that protect us and allow us to thrive come from what we pull out of the earth. Our medicines are dependent on plants and compounds that plants create, and our smartphones rely on rare elements mined form across the planet. Our dependence and demand for what the earth has to provide is very real and feels much larger than any one individual, making our personal responsibility feel tiny in comparison. Nevertheless, it is important that we use what the earth has to provide in a rational and reasonable manner, recycling what we can, eliminating waste when possible, and constantly striving to take things from the planet in the least disruptive manner. This responsibility is difficult and expensive, which is why the commons are ignored leading to the tragedy they face. We must understand that pollution, imbalanced extraction, and continued consumption do have costs that are greater than their immediate benefits, even if we only see the benefits now and can’t understand the costs of the future.