Ever since Darwin shined a bright light — by far the brightest — into the deep and dark cavern of the mystery of life, there has been some progress in understanding how human minds have evolved into their present form. While it is no doubt that the development of the human mind is a Darwinian matter and will ultimately be explained under Darwinian terms, the exact mechanisms by which the human mind has evolved still remain a mystery.
It is my contention that the best explanation that has been advanced for understanding the evolution of the human mind is the underrated theory of the cognitive niche popularized by Steven Pinker, but first proposed by anthropologists John Tooby and Irven DeVore in the 1980s.
In biology, a niche is the ecological fit of a species to its environment. The niche of a particular bird species, for example, might be a species of tree in which certain kinds of insects that the bird preys on are found. The bird will spend most of its time in that tree, build its nest there, and so on.
The cognitive niche is the distinctly informational, rather than ecological, fit that Homo sapiens have with their environment. The idea that humans have evolved to fit the cognitive niche, is simply the idea that people are distinct from all other animals in that they transform and fit their habitats — no matter how initially inhospitable — to their needs and goals rather than the other way around. People do this by bypassing the rule of biological adaptation, namely, physical interaction with the environment, and embracing informational and cognitive methods of interacting with the world: reasoning, cooperating, and communicating.
The idea of the cognitive niche stems from a simple yet profound observation. Humans managed to step outside of the coevolutionary arms race that characterizes what Darwin called, the “struggle of existence” for every other life form. For every other organism, one individual’s success is achieved at the loss of another, namely, one individual consuming another. Lions prosper only at the death of Zebras and Zebras prosper only at the death of lions.
The same logic is true for all predator-prey interactions and all parasite-host interactions. One agent in the coevolutionary arms race, say a herbivorous prey animal, gains beneficial adaptations that enable it to have greater sensitivity to the presence of predators via more sensitive hearing and seeing. This increases its chances of detecting and preventing it from being hunted by predators and thus surviving. However, in response to these prey adaptations it is beneficial for predators to develop adaptations in return, such as stealthier and quieter approaches, to overcome this fitness decrement of having more sensitive prey. These predator adaptations, in turn, put selection pressure for additional prey adaptations to become even more keen and so on in an arms race.
Humans, on the other hand, have managed to step outside of this form of coevolutionary arms race by reasoning, cooperating, and communicating with one another. These cognitive adaptations allow information and knowledge to propagate throughout the species at a speed and efficiency far greater than that allowed by biological evolution. Instead of having to encounter plant toxins recurrently over evolutionary time in order to develop biological countermeasures against being negatively affected by plant toxins, (like the predator-prey arms race I mentioned above) humans can simply learn what species of plants are toxic and avoid them.
Additionally, humans learn that there are methods by which plant toxins can be neutralized (e.g., boiling, peeling, cooking, etc.), rendering plant nutrients safe for consumption. In both cases — avoiding plant toxins and transforming them for safe consumption — instead of “learning” via the slow process of biological evolution, humans cognitively represent the cause-and-effect relationships between aspects of their environment (which includes all other organisms as well as other humans) and exploit that information by reasoning, making inferences, storing it away as memory, and passing it on through language.
People use knowledge learned and passed on by reasoning, not only to neutralize plant toxins, but also make tools to help them procure sources of food; use technology to build shelter and protect them from the forces of nature; develop weapons to protect themselves from danger, and to hunt animals that were once their predators; extract poisons and toxins from plants and animals and use it against other animals and so on, ad infinitum.
While the cognitive niche theory of human evolution sounds sensible, its correlation with truth isn’t made any stronger through mere description. Any adaptation must have a functional explanation for its existence. Functional explanations for adaptations must refer to increased reproductive success of the organisms possessing those adaptations, because adaptations are beneficial precisely because they increase an individual’s fitness relative to others. For example, whiter polar bears in the Arctic were more successful at surviving and reproducing and therefore passing their genes on to the next generation than darker polar bears. This is because the former were better camouflaged against the white snow and thus stealthier in their hunting tactics compared to darker polar bears, which were more easily spottable by seals and thus failed to hunt their prey causing them to starve more frequently relative to whiter polar bears. This resulted in the whittling of the polar bear gene pool down to only possessing white fur genes.
Moreover, explanations for adaptations have to weigh in the costs relative to the benefits of the adaptation. The cognitive niche theory of the human mind is basically a theory of the immense intellect of humans. But enormous intellect is not something that evolution inevitably leads to. In fact, it is something that begs for an explanation. Under what circumstances should humans have evolved such an immense intellect? The circumstances must have been such that the benefits of having an increased intellect outweighed the costs. But what could be the costs of greater intelligence?
A larger intellect means a bigger brain and a big brain requires a lot of energy. It turns out that the brain makes up 2% of a human’s body weight and yet sucks up 20–30% of consumed calories. Moreover, a big human brain with a gel-like consistency, situated at the end of spinal cord, floating in a bone case at the tiptop of a clumsy bipedal creature as ourselves is more fragile and susceptible to injury. Another cost of having a big brain is incurred on mothers giving birth to fetuses with exaggerated head sizes, since mothers experience great pain and risk injury from childbirth. These problems show that a greater intellect is not something that is gained without a cost. Therefore, the benefit of having a greater intellect must have outweighed those costs. Could the benefits have been great enough to do so?
Several explanations have been offered for the cognitive niche theory of the human mind. Steven Pinker describes potential factors that enabled humans to move into the cognitive niche: prehensile hands, tool-use, meat-eating, bipedalism, and group-living.
Take meat-eating, for example, which is my favorite factor driving humans into the cognitive niche. Meat not only serves as a great source of calorie-and nutrient-dense food for such an energetically costly and resource-consuming organ as the brain, but it also forces humans to outwit their prey. Humans use their brains to reason about hunting strategies, to communicate and to cooperate with other humans about how they should find, approach, kill, or escape an animal, and what their plan is if the animal does X instead of Y. The only advantage humans would have over the big game they hunted and over the big game that hunted them would be in brainpower, not speed, stamina, strength, or natural formidability.
For these reasons, meat-eating might have been one of the most important changes that caused humans to move into the cognitive niche and shift more of their energy, attention, and time into reasoning, cooperating, and communicating. Support for this hypothesis comes from research done at the University of Oxford showing that cooperation and intelligence can coevolve. As the head of the study, Zoologist Miguel dos Santos writes,
“cooperation initially evolves, favouring enhanced cognition, which favours enhanced cooperation, and stabilizes cooperation against a drop in relatedness.”
In other words, Miguel dos Santos’s research identifies that cooperation in, say, the form of hunting for meat, could have occurred first, which would have then favored increased cognition, which would have enhanced cooperation, and so on, in something like a positive feedback loop. Additional evidence supporting the cognitive niche theory would be signs of selection in human genes affecting intelligence, language, and sociality and comparing those differences in allele frequencies for those traits with our primate ancestors. Many studies do show this.
What the cognitive niche theory has to say about human evolution is not only explanatory but awe-inspiring, for human beings are different from animals in being limited by ecological constraints, whereas human potential to understand and create knowledge is as infinite as language and reasoning.
As Deutsch argues in, The Beginning of Infinity, humans are distinct from all other creatures in being able to use explanatory knowledge as opposed to other forms of knowledge. All other creatures and the knowledge they embody are a product of Darwinian biological adaptation, which is a form of knowledge creation and growth, but it is limited in several ways.
The main limitation to biological adaptations is the limited reach they have. A biological adaptation for a bird wing, for example, has great reach in the sense that if the bird travels many miles in any direction horizontally, wings can serve it well. However, if it flies just a little bit of distance vertically into the atmosphere, it would quickly not have enough air to support its flight because of low air pressure. The same is true for the eye, which would freeze in the cold temperatures of the upper atmosphere, or the ear which has no use in airless space. In this sense, biological adaptations have great reach, but nothing close to infinite reach.
Humans, on the other hand, have the potential to develop knowledge of anything and everything and that knowledge may very well apply to worlds not yet discovered on the other side of the universe. Deutsch uses the example of the explanation for seasons as one that extends through time explaining what scientists did not yet know was an explanation for seasons until people had the inclination to conceive it.
What started out as a simple theory in a person’s mind about spinning geometrical spheres that tilt toward and away from radiant heat would go on to explain nearly everything there is to know about seasons, from why they are necessarily out of phase on different parts of the globe, to why seasonal change is altered if one moves north or south rather than east or west. In other words, the good explanation for seasons (and for that matter, potentially any good explanation for anything that humans conceive) reaches out infinitely through the universe explaining seasons on planets not yet discovered. And if people fail to find seasons on some planets, the axis-tilt theory would also explain the absence of them. A good explanation of this form holds true no matter the knowledge a human mind happens to carry about that theory at any point in time. Truth really is out there awaiting discovery.
People develop knowledge mainly through conjecture and criticism— where new theories for how things work are imagined and subsequently sifted through a sieve of experimentation and refutation. In this sense, human knowledge grows in a similar vein to biological evolution. Random mutation in the latter process is analogous to conjecture, and the sieve of natural selection is analogous to criticism. Random mutation and conjecture are similar in that they far more often lead one astray from the path of progress in the form of deleterious rather than beneficial mutations and fictional rather than truthful conjectures. Natural selection and criticism are similar in leaving behind that which is left standing among the ruins of false theories.
From my account above you might be led into thinking that biological evolution strives for some purpose or goal towards ever-more advanced forms, but this is not true. In fact, that is the difference between rapid human progress fueled by explanatory knowledge and the slow growth of knowledge created by biological evolution. Humans can set a goal and quickly achieve it and that goal need not be related in any degree to their biology. In fact, it is often directly opposed to their biology.
As David Deutsch writes in, The Beginning of Infinity,
“The ability to create and use explanatory knowledge gives people a power to transform nature which is ultimately not limited by parochial factors, as all other adaptations are, but only by universal laws. This is the cosmic significance of explanatory knowledge — and hence of people, whom I shall henceforward define as entities that can create explanatory knowledge.”
The defining difference is that in contrast to knowledge encapsulated in biological adaptations, human explanatory knowledge and human transformation of the physical world is constrained only by what is permissible within the laws of nature. So, there would be no such thing as resource shortages if humans can acquire the knowledge required to transmute hydrogen — the most abundant element in the universe — into all other elements. Of course, physicists already know how transmutation works. It’s how the sun shines. But humans will require much more knowledge in order to harness this power without destroying themselves and all life as we know it. Similarly, there would be no such thing as global warming if humans can acquire the knowledge to regulate the climate like a thermostat in one’s house, something that is certainly possible within the laws of nature and eminently desirable.
How wondrously fascinating is it that reality works in such a way as to not only by explicable by us humans beings, but also to be so varied as to create things as different from each other as black holes and human minds. And yet, reality is also uniform enough in its principles so that human minds can understand how black holes form and what it would be like to approach one, and be sucked into one even though nobody has been.
How fascinating is it that seemingly insignificant and unimportant human beings located on this little pale blue dot (as Carl Sagan put it) caught in the sun’s light beam can imagine the universe and actually be right about it. That’s really something isn’t it?