We tend to think of humans as developers of technologies. But how often do we think about technology as a shaper of humans? Usually when we do so, we imagine changes to our individual lives: The advent of the internet, for example, or the emergence of Facebook. Yet throughout history, technology has affected humans on a much deeper level – that of biology. As technology and culture continue to influence human life on a broad scale, we should consider the possibility that current trends and social behaviors may affect human evolution generations down the line.
Technology has been at the heart of our species since the dawn of humanity. Perhaps as early as 3.4 million years ago, the modern human ancestor Australopithecus afarensis was using stone tools to strip meat from the bones of large mammals. By about 12,000 years ago humans were practicing agriculture, which enticed people to abandon their nomadic lifestyles and develop the technologies we now recognize as essential to civilization.
Technology – and by this I mean physical tools as well as ideas and practices – has influenced human biology in some surprising ways. For example, meat-eating in humans, which in the archaeological record is tied to stone tools for crushing, cutting, scraping, and hunting, may underlie the evolution of intelligence. Scientists have puzzled over a link between weak jaws and bigger brains, the key idea being that skull growth is inhibited by large jaw muscles. Weak jaw muscles are a disadvantage where serious biting and chewing are concerned. Eating meat requires less robust dentition than eating nuts, seeds and berries, so a diet change would remove the pressure for strong jaw muscles and pave the way for bigger brains – in addition to enacting a plethora of other alterations to the skull and gut. (Meat also supplies more energy per unit weight than plants, ensuring that humans could power all that extra gray matter.)
In fact, cooking may make strong jaw muscles even less necessary because heating tough, fibrous foods softens them. And according to Alfred W. Crosby in “Children of the Sun,” a major revolution in human history occurred when ancestral humans began cooking, providing the genesis for complicated social behaviors and expansion to previously unoccupied ecological niches. So from the perspective of what’s “natural,” diets like raw veganism may not make sense for modern humans. Eating meat and cooked food may be as entrenched in our genes as it is in our society.
The extent to which human-driven phenomena, including technology and culture, can affect human nature itself raises an interesting philosophical question: Should our goals for societal development include mindfulness of how Homo sapiens evolve in response?
The issue is particularly interesting given that the rate of human evolution may actually be increasing because there are more humans alive today than ever before. And if the fertile really do inherit the Earth, what might that say about future population demographics given the differential reproductive rates of people in developing vs. developed countries and even within nations between, say, the average Mormon and the average non-Mormon?
But most controversial is the notion that human races may be evolving away from each other as environmental and cultural factors create situations that favor different traits. Such an effect may already be observed in the lactose tolerance of ethnicities that historically domesticated cows and the different levels of alcohol tolerance between ethnicities (including the famous Asian flush). For those of us who don’t want Homo sapiens to fracture into multiple distinct species, it’s worth taking a moment to think about the consequences of emphasizing differences over commonalities. Some conflict may be inevitable, but a rhetoric of unity should eventually dominate our societal conversation.
Although the rate of technological change far outpaces that of human evolution, the only “natural state” for humans – and for the Earth – is flux. We can’t deny that we are interconnected with technology. We can’t turn back the clock and become hunter-gatherers in the sense that our ancestors were, any more than we can exactly predict the evolutionary consequences in a million years of what we do today.
Yet we should take heart in the biological adaptability of humans to changing circumstances, even as we are mindful of the trade-offs we make as a result of technological dependence – like exchanging nut-chewing for intelligence. When we imagine the kind of future we want our descendants to inherit, we should bear in mind that they will not be Homo sapiens as we know them. They will go on evolving right alongside technology – and maybe complicitly, we will have contributed to that evolution.
Assuming the robots don’t take over first, of course.
Contact Mindy Perkins at mindylp ‘at’ stanford.edu.