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What’s wrong with us? Not us Democrats, Republicans, or Americans. Rather, what’s wrong with our species, Homo sapiens? If human beings are as Hamlet suggested, “noble in reason, infinite in faculty,” then why are we facing so many problems?
In many ways, people are better off than ever before: reduced infant mortality, longer lifespans, less poverty, fewer epidemic diseases, even fewer deaths per capita due to violence. And yet global threats abound and by nearly all measures they are getting worse: environmental destruction and wildlife extinction, ethnic and religious hatred, the specter of nuclear war, and above all, the disaster of global climate change.
For some religious believers, the primary culprit is original sin. For ideologues of left, right, and otherwise, it’s ill-functioning political structures. From my biological perspective, it’s the deep-seated disconnect between our slow-moving, inexorable biological evolution and its fast-moving cultural counterpart—and the troublesome fact we are subject to both, simultaneously.
Imagine this. An infant born on the Pleistocene savannah is switched at birth with another born in 21st-century America.
Biological evolution is an organic process that can never proceed more rapidly than one generation at a time, and many generations are nearly always required for any appreciable change to occur. By contrast, cultural evolution is extraordinary in its speed. Biological evolution is Darwinian, moving by the gradual substitution and accumulation of genes. Cultural evolution is Lamarckian, powered by the nongenetic “inheritance” of acquired characteristics. During a single generation, people have selectively picked up, discarded, manipulated, and transmitted cultural, social, and technological innovations that have become largely independent of any biological moorings.
In their early stages, these two processes would likely have been mutually reinforcing. Our capacity for culture is itself our most potent biological adaptation, enabling a population of weak-bodied Pleistocene primates to gain ascendancy over most of the world. At the same time, as cultural evolution proceeded and we endowed ourselves with language, impressive cognition, complex social organization, and increasingly potent technology, the ability to employ these skills to master our immediate environment almost certainly outran our biological evolution.
It seems inevitable that as these cultural skills developed and provided leverage over the material and natural world—not to mention over other human beings, less adroit at these things—natural selection favored those individuals most able to take advantage of such traits. Up to a point, our biological and cultural evolution would have been mutually reinforcing. We are now past that point.
There is no reason for our biological and cultural evolution to proceed in lockstep, and many reasons for them to have become disconnected. Biological evolution is chained to genetic change; indeed, that’s what biological evolution is. Cultural evolution is entirely different. Although it depends on a biological infrastructure (it takes brains to make a fire, a computer, a functioning language, a hydrogen bomb), cultural “mutations” can arise and be adopted, modified, and passed along within days, without waiting for the passing of even a single biological generation. I wrote this on a computer, having purchased my first word processor in the 1980s. Before that, I wrote on an IBM Selectric typewriter, and before that, on a Smith Corona manual. All within just one lifetime.
If my use of a computer depended on biological evolution, and if I had invented the computer in the 1980s, then at most one or two of my daughters (and their toddler offspring, my grandchildren) would currently be using computers. Instead, literally billions of people are doing so; not only that, but they are using technology that is updated every few years. During that time, of course, there has been effectively no change in the biological nature of Homo sapiens.
Imagine this thought experiment. An infant born on the Pleistocene savannah is switched at birth with another born in 21st-century America. Each would undoubtedly grow up to be a functional member of her society: hunting mastodons or gathering roots and berries in one case, and perhaps running a hedge fund or piloting jet aircraft in the other. Now, delay a few decades and switch these two individuals as adults; the results would be disastrous for both. The biological nature of these individuals will be comparable whereas cultural evolution will have produced qualitatively different circumstances in the two cases, such that individuals carrying only their shared biology into each situation would find themselves woefully unable to function in the other’s cultural milieu.
Up to a point, our biological and cultural evolution would have been mutually reinforcing. We are now past that point.
This discrepancy italicizes the gulf between our biological and our cultural selves. Moreover, the rate of these changes and the dimensions of our biology-culture discrepancy has itself been accelerating. Recalling Kenneth Grahame’s 1908 classic The Wind in the Willows, our species has been on Mr. Toad’s Wild Ride. Exciting, yes. But also dangerous. In Aesop’s classic race, the tortoise wins because the hare is overconfident and downright foolish. In human reality, though, both are part of ourselves. The problem is our hare-y alter ego outpaced our inner tortoise, which has not evolved to deal effectively with the risks presented by our speedy culture.
Let’s think about our species-wide sweet tooth. Primates all, we evolved in trees with a special predilection for ripe fruit. Ripeness indicates maximum nutritional value—a lure to get arboreal creatures to consume them, after which the seeds are pooped out elsewhere, surrounded by nutrition-rich fertilizer. So far, so biological. Not surprisingly, ripe fruits and fruity flavors still exert a biological attraction for modern Homo sapiens. Also, to no one’s surprise, people have seized on this fondness via cultural practices that generate “sweets” that are nothing but sweet—that is, devoid of nutritional value. They are, however, deeply satisfying, not to mention remunerative to chocolatiers, bakers, processors of sugar and high fructose corn syrup, and dentists.
A similar dietary situation pertains to fats. Wild game is notoriously lean, and yet fat is calorically dense as well as relatively rare during 99 percent of our evolutionary past. When available, a fatty meal would have been highly valued. Today, not only can we pander to our fondness for “empty calories” in the form of highly sugared drinks and desserts, but we have the luxury of treating ourselves to highly marbled steaks, courtesy of feed lots and industrial agriculture, along with the gustatorially appealing fat present in bacon, burgers, butter, cream, and fried foods of all sorts. The beneficiaries, in addition to the denizens of corporate animal husbandry, include cardiologists, coronary bypass surgeons, diet consultants, and undertakers.
Let’s look now at another related example: exercise. There are, of course, people who enjoy exercise, who go out of their way to get it, often paying large fees to join athletic clubs, gyms, and hire fitness gurus. But it’s also notable how many gym memberships go unused, how many home exercising devices end up collecting dust in the basement, and how serious is the increasingly worldwide obesity epidemic, despite the unambiguous medical assessment that aerobic activity is beneficial for maintaining cardiovascular health, appropriate body weight, and protecting against a range of degenerative and inflammatory diseases.
Why don’t people get more exercise? Much of the blame resides, once again, in the disconnect between the imprint of our biological past and our present-day predilections made available by our cultural interventions. There is debate among paleo-anthropologists over precisely how much exercise our savannah-dwelling ancestors normally experienced, but it is unlikely that they took elevators or escalators, commuted by bus or automobile, spent their weekdays at a desk and their weekends on a couch watching golf. For most of our evolutionary past, it was probably difficult to avoid getting heavy doses of exercise, and a good idea to minimize it when possible.
Our biology-culture disconnect is not limited to matters of nutrition, exercise, and health. Its imprint can be seen in nearly every big-picture problem we currently face. Enter global heating (a better word than “warming,” which carries misleading connotations of comfy and toasty). Insofar as the combustion of fossil fuels generates millions of tons of carbon dioxide, which, via the greenhouse effect, absorbs heat from the sun while preventing much of it from being radiated back into space, our technological hare has set the pace. This phenomenon is largely due to the industrial revolution, barely more than two centuries old, during which time our biological evolution has essentially remained unchanged. Rapid cultural evolution has bequeathed us 50 percent of the problem: the physical and chemical half. At the same time, slow moving biological evolution has left us both reluctant to acknowledge the problem and—even when that psychological roadblock is surmounted—often disinclined to do very much about it. Why?
Go back to our weak-bodied, savannah-dwelling ancestors. Although some regular environmental variations were doubtless recognized and anticipated—such as daily and seasonal cycles—excepting certain rare events such as asteroid impacts or earthquakes, changes would have been so gradual as to be almost imperceptible. I don’t know if anyone has actually tested the cliché that a frog dropped in boiling water will immediately jump out, whereas the same amphibian placed in cold water that is imperceptibly heated will not notice the gradual change, and die of heatstroke. But the metaphor is compelling. It has similarly been observed that if the air pollution that now afflicts so many great cities had arrived overnight, the inhabitants would have run screaming into the hills; as it is, residents by and large accept the deterioration of their immediate environment and wonder about the strange blue sky that blows in every now and then.
Our biologically evolved selves are quite good at perceiving events that are prompt and threatening; those that are slow-moving, although equally threatening, not so much. A fire in a building and people run outside. A slow moving fire in the Earth’s thermal budget and people hardly notice. For nearly all of our evolutionary past, it was not adaptive to detect such slow-motion changes, and so our ability to do so is limited.
There is debate over how much exercise our savannah-dwelling ancestors experienced, but it is unlikely they took escalators.
Quick events, not surprisingly, evoke quick responses. In the past, a sabre-tooth about to leap; in the present, a car approaching too fast. Similarly, we are exquisitely sensitive to the immediate past, which made us good at responding to a location, where we might have found food, or narrowly missed becoming food. It is a selective sensibility that now readily misleads us. We are inclined to interpret the latest cold snap as evidence against global heating, or, on the other hand, a heat wave as confirming it. Long term trends leave us confused and psychologically indifferent, just as we are largely insensitive to statistical compilations—highly significant though they are—such as a long-term, 2-degree-Fahrenheit temperature rise.
In addition to being dangerously indifferent to slow-moving changes, it seems likely that our ancestors were predisposed to refrain from struggling with problems that were on a global, continental, or ecosystem scale. Recent evidence suggests that in the prehistoric past, early humans were responsible for the extinction of some of the Earth’s large mammals, events that would have had ecological consequences. But for the most part, those relatively rare, weak-bodied primates limited to Stone Age technology weren’t able to act as major geological and biological sculptors of the planetary environment. Our numbers were too small and capabilities too limited. Moreover, there was nothing our great-great-etc. grandparents could have done about whatever changes nature might have wrought.
And it would not have been in their adaptive interest to try. There is no payoff (emotional, psychological, social, or biological) to wrestling with a tornado or struggling to cap a volcano. Any who tried wouldn’t have benefitted from the effort, and might well have left few if any descendants compared to those who saved their energy for more manageable threats. An enemy with an upraised club was one thing; a raised ambient temperature—no matter what its cause—would have been quite another.
Very little in the realm of human behavior is caused by just one thing. Similarly, few of our problems result from simple, unimodal cause and effect. When it comes to global climate change, there is little doubt that politics, economics, and social factors are implicated, not only in causing the problem but interfering with our ability to perceive and deal with it effectively. But the strictures placed on our psychology by the conflict between our rapidly moving cultural and technological hare and our glacially slow Darwinian tortoise are also to blame.
As I’ve said, cultural evolution has provided us with huge benefits. Few people would choose to live without antibiotics, readily available food, shelter, and communication. At the same time, we cannot adjust our biological evolution to make it congruent with its cultural counterpart, at least not within any reasonable time scale.
Our situation is not hopeless. We are not doomed to plod into an overheated future, prisoners of our slow-moving genomes and at the mercy of our hare-brained, rapid-moving, C02-spewing technology. The human species is capable of remarkable and adaptive adjustments—not of our biological evolution (that’s ethically questionable and too slow in any event), but in our cultural actions. Indeed, it is because of our big, biologically evolved brains that we possess this capacity.
Consider, of all things, toilet-training. We are clearly more intelligent than dogs or cats, and yet it often takes three or more years for young Homo, ostensibly sapiens, to learn to pee and poop in a toilet, whereas our household pets learn the trick almost immediately. An evolutionary perspective suggests why. Arboreal creatures, as our ancestors were, have no reason for their DNA to be encumbered with a penchant for tidy potty habits. By contrast, dogs and cats evolved in a two-dimensional world where it was maladaptive for them to foul their dens. Hence it is easy for them to become house-broken.
I submit that everyone reading this article—primates all—have been toilet-trained. Thanks to our cultural evolution, we have cities, houses, and indoor plumbing. As a result, to the benefit of our health, we learned to use toilets. A primate with such behavioral flexibility, capable of going against millennia of natural selection, is nearly miraculous, yet an everyday event. Take heart. An originally arboreal primate species capable of being toilet-trained should also be capable of becoming planet-trained. In Aesop’s tale, remember, the tortoise triumphs. Because the hare and the tortoise are both part of ourselves, they can only win or lose together, which makes it all the more important that we get our hare-brained selves under control.
David P. Barash is an evolutionary biologist and professor of psychology emeritus at the University of Washington. His most recent book is Through A Glass Brightly: Using Science To See Our Species As It Really Is.
Lead image: frantic00; Maureen Perez / Shutterstock
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