Uniquely Human

What separates us from other animals?

The Future of Human Uniqueness

Will our minds become even more unusual?

Dawn of the Planet of the Apes
Will great apes close the gap?
Dawn of the planet of the apes
There appears to be a gap separating the minds of humans from even our closest animal relatives, the great apes. What is the future of our special status on Earth? Will the gap increase, decrease or remain the same?

The view that the gap is stable may derive from a belief that humans are no longer evolving—a perspective quite widely held. Could it be that cultural and technological advances mean biological evolution no longer matters to us? We have become so powerful in creating artificial worlds that we primarily seem to adapt the environment to us rather than the other way around. Modern medicine increasingly circumvents natural selection, and our global interconnectedness means there are no longer many isolated pockets in which human evolution can diverge. Has the evolution of our minds stopped?

On a moment’s reflection this scenario seems rather unlikely, and even reeks of arrogance, as it seems to imply that we are the final product—the height and endpoint of evolutionary achievement. I find it difficult to believe that after four billion years of life forms changing on the planet, it all comes down to the perfection that is you and me. Given our past, it seems more likely that we are another segment in the long chain of evolutionary change. Tens of thousands of generations from now, if we manage to not go extinct, our descendants will look back at us as early humans. In fact, there is evidence that even over short time frames natural selection is effective in bringing about genetic changes in human populations. Furthermore, natural or human-made disasters can create isolation rapidly—as could human success: just think of the possibility of humans eventually populating other planets. Those who do go extraterrestrial may quickly find themselves isolated and available for separate evolutionary trajectories. In sum, it is highly unlikely that evolution will stop with us.

What, then, is the trajectory of the evolution of the human mind? Some data suggest that over the last ten thousand to fifteen thousand years, as population density increased, brain sizes decreased. Given associations between brain size and IQ, this may reflect a decline in mental ability over the time we gained most of our amazing technological powers. Potential reasons for this decrease are changes in nutrition and climate, as well as the possibility that our societies, with extensive division of labor and social safety nets, enable the less mentally endowed to survive where in the past they would not have reproduced. Many of us get by without having the basic skills of hunting and gathering that had been essential for our forebears. Perhaps as technology does more and more of the hard work for us, our artificial world will put ever less demand on our minds. It is imaginable that in the future we will all sit in our lounge chairs and play in virtual reality. Is it possible that our mental capacities are dropping and the gap will become smaller?

It seems unlikely that our minds will dumb down dramatically as long as humans are needed to design and maintain these artificial systems. However, the forces of natural selection on humans today are puzzling. The rich, successful, powerful, beautiful, and well-educated people seem to breed less, not more, than most of the rest of us. In other words, they appear to leave fewer copies of their genes in the next generation than those not blessed with these seemingly highly advantageous attributes. One may therefore worry humanity will slowly lose its edge and the gap eventually gets smaller as a result.

It is also possible, of course, that we cut short our own success story more dramatically. In addition to radically changing the environment, our arms races have resulted in weapons that enable us to annihilate each other many times over. War, terrorism, or mishaps could quickly result in a dramatic unraveling of our civilizations. If we somehow mess it up, our minds may struggle to rebuild, especially as we become ever more dependent on technology. As Einstein warned, “I do not know with what weapons World War III will be fought, but World War IV will be fought with sticks and stones.” Countless civilizations have collapsed. In addition to violent conflicts, common causes include habitat destruction, soil and water management problems, overhunting and overfishing, introduction of new species, and overpopulation. As we are increasingly linked into one system, and we face many of those problems on a global scale, it is possible our modern civilization too will collapse one day for similar reasons. A potentially bleak future awaits in which few survive and other creatures are given a chance to close the gap.

A scenario like the one in the 2011 film Rise of the Planet of the Apes (and its 2014 sequel Dawn of the Planet of the Apes), in which we unleash a deadly pandemic while simultaneously enhancing the capacities of apes through biotechnology, is highly unlikely but not entirely out of the question. Genetic engineering has given us radically new powers to influence evolutionary pathways. Advances in biotechnology, such as the capacity to turn any cell into a stem cell and use it to grow body parts or entire organisms, will open up incredible opportunities. It is not far-fetched to assume that we may one day be able to alter brain development and enhance the minds of our closest remaining relatives. Humans are increasingly guiding evolution itself. Some call this “playing God.”

Humans have played God for a long time. At least since the beginnings of agriculture humans have practiced what Darwin called “artificial selection.” We encourage versions of plant and animal life that are useful to us and discourage those that are not. Artificial selection may also have been important in the shaping of our own species. Hitler’s genocides and attempts at breeding a superior race may be the first things to spring to mind, but we socially guided our evolution long before any notions of eugenics. Capital punishment and banishment from social groups not only enforce social norms but select against certain undesirable attributes, such as tendencies to rage violently. We may have domesticated ourselves much as we have domesticated dogs and horses. Domesticated animals are not only less aggressive and more cooperative than their wild counterparts but also typically sport smaller brains. So this proposal is in line with recent human brain size reduction and the overall decline in violence and increase in cooperation that Stephen Pinker argued has characterized recent history.

We have gained some significant new capacities for what we might call “auto-artificial selection.” Contraception is the most obvious, letting us curtail reproduction. Conversely, we can make sperm fertilize eggs in ways other than through sex. We will increasingly have the opportunity to deliberately determine not only the number of offspring but also their characteristics, from sex to disease resistance. Many people have understandable reservations about such interference. But imagine if you could make the genetic changes to stop your child from getting cancer, Alzheimer’s, or whatever else has plagued your family tree. It is a small step from preventing disease to influencing the intellectual capacities of offspring or altering the shape of the nose. This direct interference in the genetic makeup of the next generation—“artificial mutation” rather than just artificial selection—may lead to drastic changes as we fast forward tens, hundreds, or thousands of generations into the future. We are increasingly acquiring the power to shape our own evolution, and we may well end up using it to acquire greater mind power.

I predict that the gap will widen. In fact, there are signs it already is widening. Over the past century humans have improved in their average performance on intelligence tests by about 3 percent every decade. Some evidence suggests that brain size, contrary to the trend of the last ten thousand years, may have slightly increased over the last 150 years. We have more nutritious foods and more stimulating education. We bolster our scenario-building minds with ever more refined machines and technologies that allow us to measure, model, and control the world in increasingly powerful ways. Through the internet and other electronic networks we are connecting millions of minds and bringing about an explosive growth in cultural accumulation. Answers to most questions are only a few clicks away. Science is accelerating, and greater knowledge in turn will open doors for the already foreshadowed biological, as well as electronic or chemical, enhancement of human mental powers. We are getting ever smarter—and, one can only hope, wiser.

There is a second way through which we may increase the gap. We could make ourselves appear more special on this planet by reducing the capacities of our closest animal relatives—moving the other side of the chasm. I do not mean we somehow dumb down the apes; I am referring to driving them to extinction. Their demise would turn other species into our closest living relatives, thereby widening the gap. Let’s face it: we are in the process of doing just that. All the great ape species are endangered, and their numbers are primarily declining for one reason: human activity. Whether through habitat destruction, bush-meat consumption, or the pet trade, we are causing the demise of our closest animal relatives, perhaps not entirely unlike what we might have done to our upright-walking hominin relatives in the past.

In a couple of generations, our descendants might wonder at just how different they are from their closest remaining animal relatives: the monkeys. Apes may join Neanderthals and Paranthropus as half-forgotten creatures of the past. With the demise of our smartest animal relatives, the human mind would appear ever more special on this planet. And so our descendants may become even more baffled by their own apparent uniqueness. But we can prevent this from happening. Plan it for the apes. We can safe our ape relatives from extinction and we can encourage others to become more informed about the nature and origin of our special status on Earth.

 

Thomas Suddendorf, Ph.D., is a Professor of Psychology at the University of Queensland.

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