Wired for Culture: Origins of the Human Social Mind (48 page)

If this process is allowed to run for a long time, a smaller and smaller number of increasingly larger mounds will spontaneously emerge. This is because early on, and just by chance, there will be variation in the size of the mounds. Termites wandering around carrying chips will tend to encounter the larger mounds more often, and in that way the mounds become “attractors” for yet more chips. True, termites are more likely also to pick up chips from the larger mounds, but for the reason just stated these chips will tend to be dropped at larger mounds. Eventually, one of these mounds will attract all the chips. At that point, empty-mouthed termites pick up chips from the single mound but then wander aimlessly until they bump back into it and deposit the chips again.

With one simple rule we have got our hypothetical termites to create a highly non-random structure. We might be tempted to praise them for their insight and cooperation, but none of the termites set out to make a mound, and none of them had a blueprint of the mound in their minds. The final “design” is not a design at all but emerges from collections of individuals acting as agents following simple local rules. We know this because were we to set them the same task again, a different mound would appear, and it would be in a different place. But the mound would look much the same as the first one, and the process that led to it would be the same. You can see this for yourself because computer programs that allow you to simulate this termite behavior can easily be found on the Internet.

Now, a heap of chips of wood is not a termite mound, but it is a good start. The tall monolithic mounds of the compass termites we saw in Chapter 2 are made of mud, not wood chips. But these too emerge from agents—possibly hundreds of thousands or more of them—following local rules that vary, depending upon circumstances in the environment. Maybe one simple rule that initiates the building of a mound is to pick up a bit of mud and drop it whenever you encounter another drop. Just as with the wood chips, this will begin to construct larger and larger mounds. Maybe another rule gets workers to hollow them out. Maybe inside one of these mounds a rule instructs workers to “drop some mud on the spot where you feel a blast of cold air.” This is a rule that will help to regulate the temperature or patch up holes that could let in rain or intruders. The termites don’t need to “know” what they are doing, they just need to follow the local rules, making their behavior contingent on what is going on around them. Natural selection acts on these rules because termites that carry genes “for” these rules build better mounds, and are therefore more likely to survive and reproduce, sending their mound-building strategies into their offspring.

One of the earliest and most pleasing demonstrations of complex behaviors emerging from agents following local rules was Craig Reynolds’s simulation of the motions of flocks of birds as they fly around in the evening sky feeding on insects. The fluid and flowing motions of these flocks wheeling around the sky, sometimes separating and then coming back together, avoiding collisions with each other, looks to be a supreme act of purposeful cooperation on the wing. But Reynolds achieved a surprisingly realistic simulation by assigning the individual birds just three simple rules: one is to stay near to and steer in the same direction as your nearest neighbor; the second is to follow the main heading of the group; and the third is to avoid crowding. Add to these rules a small amount of randomness to individuals’ behaviors, and flocks of “boids,” as Reynolds called them, elegantly and sublimely fly around computer screens. No one bird is directing the flock and the birds are not actively cooperating to produce it. It emerges from the simple rules.

The wonder of what biologists call our
ontogeny
, or the sequence of development of our bodies from a single fertilized egg, is that these immensely complex structures get built without anyone in charge, no little homunculus directing traffic or reading from a blueprint. This happens even though every one of our cells carries the same instructions encoded in our DNA. And yet, some will end up as teeth, others as eyes, or parts of your brain or kidneys, heart or liver. How do they know what to do? We know they don’t follow a predetermined plan because identical twins carry exactly the same genetic instructions but their bodies are not identical. Thus, we don’t develop by building first a skeleton and then having parts added the way one might assemble a car or other complex piece of machinery. Rather, our bodies emerge gradually and piecemeal as our cells repeatedly divide and assume different forms in different parts of the growing body in response to differing local conditions.

Thus, early on in our embryonic development, we are but a growing and mostly undifferentiated ball of cells called the
blastocyst
attached to the uterine wall via the placenta. It is the cells in this blastocyst that are sometimes called
stem cells
and they are described as
totipotent
because up until this point any of them can eventually become any part of your body. Some might become teeth, or parts of a kidney, eye, or liver, or they might become a fingernail or part of your brain. Gradually, as these totipotent cells continue to divide, they commit themselves in response to local conditions to become one of several broad classes of cells in our bodies. Local conditions might vary among the cells in the blastocyst because some cells just by chance are in the outermost layer of the ball, others are near to the middle, and others are in between.

When the cells begin to commit themselves, they switch from being totipotent to being
pluripotent
. They still don’t know their fates but they do have a better idea of what they might be. For instance, a cell might know that it is destined to become part of the central nervous system but whether it will be part of the brain or spinal cord is still unclear. Later yet in development—and it is thought again in response to local conditions—cells commit to particular fates such as becoming a nerve cell, a heart muscle cell, a kidney cell, an eye cell, or perhaps a liver cell. Then, the cells within each of these different tissues (again by following purely local rules) know when to stop making more liver cells, or more cells in the kidneys, or eyes. If too many of a particular kind of cell are made—perhaps too many liver cells—a phenomenon called
apoptosis
removes the excess, and even this occurs in response to local conditions.

This process of development, or ontogeny, normally works remarkably well, and it is wondrous because it just happens on its own. It produces objects of unimaginable complexity, greatly exceeding the most sophisticated objects humans build using their minds. And where our human-made objects are often prone to catastrophic failure—as when spacecraft explode or nuclear power stations melt down—the process of our ontogeny is remarkably reliable, capable of turning out our complicated bodies over and over in every species on Earth. Nevertheless, in mammals, once our cells are committed to a particular fate, they cannot be anything else. This can make car crashes, ski accidents, gunshot wounds, and growing old a nuisance because our cells do not always know how to grow back from these insults. They don’t always know how to grow back because some wounds, or simply the ravages of time, require cells to go back to an earlier cell fate to repair the damage, but this is what they cannot do.

If cell biologists could learn how to reverse committed cells back to their totipotent or even pluripotent stage, they could perform something close to miracles, which is why the field of stem cell research is pursued with such vigor. With a knowledge of how to control cell fates, scientists could make the science fiction writers look dull. The limbs and organs, nerves and body parts that they could regrow would be real, making bionic attachments like the one Anakin Skywalker gets fitted with in
Star Wars
after a light-saber accident seem primitive. It is a technology that will make transplants obsolete or just temporary, and conditions like heart disease will be treatable by growing new hearts. Nerve damage and paralysis will be reversible, and some brain diseases will become treatable. Some of these things are already happening as scientists inch by inch figure out how to reprogram cells. The current reliance on embryos to supply stem cells for this kind of research—and the moral and political debates this can produce—is a consequence of our ignorance of how to produce stem cells ourselves. Ironically, some animals—lizards, newts, and crabs, for example—already know how to do this. We know this because they can regrow their limbs, making bones, nerve cells, muscles, and blood vessels from scratch. This might just be another example of Leslie Orgel’s second rule: “evolution is cleverer than you are.”

As we have seen in nearly every chapter of this book, many of the features and processes that make our bodies work have been rediscovered by cultural evolution. We can see this again in how the individual developmental trajectory of our lives replays or reenacts the nature of cellular ontogeny. We have to come into the world
culturally totipotent
, or individually capable of enough flexibility in our ontogeny to inhabit and make use of the body we have been calling the cultural survival vehicle, and without knowing in advance what it will be like. Like the cells that construct the early part of our embryonic lives, we come into the world not committed to any particular fate (we speculated in Chapter 3 that we might differ in some innate predispositions and talents, and if we do, we could say that our personal development begins at about the point that individual cells become pluripotent). And like them, we acquire a language, customs, beliefs, and specializations as we go, in response to local circumstances. Some of us become lawyers, others artists or boatmakers, construction workers, salespeople, or mechanics. The local circumstances that influence our fates could be as simple as a local shortage of a particular skill, the presence of a teacher, something our parents told us or something about the labels they attached to us, or a current demand, such as the requirements that impending warfare might bring. The societies that emerge from this process, like an old building, are potentially immortal as we come and go, but the structure remains intact.

Like cells committed to a particular fate, once we have committed to a specialization in life, it can be difficult to return us to an earlier time of our lives when we had more options. Programs to teach people new trades or skills are like attempts to restore a cell’s totipotency or pluripotency, and just as it is difficult to reprogram cells, sayings like “You can’t teach an old dog new tricks” remind us that it becomes far harder to learn a new trade or some new physical skill, or even a second language, later in life. We might be tempted to attribute these difficulties of reprogramming simply to getting old. Surely age does play a role, but this merely raises the question of why we are built this way. The answer might be that in our past, our social environments have been stable enough that once committed to some trajectory, we would not need to change. Our brains might have evolved for earlier times, when they would not be asked to start over and do something new, such as learn a new language, or switch from being a herder to a fisherman.

Our ontogenetic wiring might be designed to crystallize from around the time of adolescence because in our past what you might have been doing at that time of your life was probably a good predictor of what you would do for the rest of your life. But the cheetahlike pace of cultural evolution in our modern world has taken this stability away, exposing the inflexibility in our development. Entire trades vanish as cultural developments render them obsolete or inefficient. How many chimneysweeps, glass blowers, shoemakers, textile dyers, or hat makers do you know? It is not hard to imagine what we would be like if we had a different kind of ontogeny—something that made us more like the lizards, but at a social level. If we could reverse years of learning and specialization and take people back to an earlier state, the results might be as spectacular as acquiring a new limb. The demands that modern cultures put on us to have this flexibility might already be favoring people whose wiring makes them more flexible and able to adapt and change throughout their lives.

If we think about it, we realize that the way our bodies develop, and our own development within society, have to be based around local rules, and not predetermined fates. There could not be any little homunculus inside us planning our bodies. It is not just that there is too much to know; this little homunculus would also have to be able to predict the future. There could not be a predetermined number of cells for each particular function in a body; or, if there were, this would strikingly limit a body’s ability to adapt to new or changing conditions. There are exceptions. The worm known as
C. elegans
does normally assign the same number of cells to each function. But this creature is constructed from a mere 959 of them and is about 1 millimeter long; it doesn’t have a wide range of behaviors; and it lives in a fairly constant environment in soils where all of them do the same thing.

Equally, and for the same reasons, no one could plan our societies, and there could not be a predetermined number of people in a society with a predetermined number in each of many different occupations. What if all of a sudden the society needed more of one particular commodity? When societies have been designed—Moore’s Utopia, Pol Pot’s Year Zero, the vast sprawling social housing estates of Western European social democracies, or the hugely controlling and interfering theocracies of the world—they have usually proved far from utopian. And human-engineered societies such as planned cities might be “optimal” in some respects but often fail to meet our expectations in other ways. Natural and cultural selection have found a set of rules that our minds haven’t yet discovered. Orgel’s second rule yet again?

If the properties of self-organization tell us how it is we can produce large societies and develop within them merely by following local rules, they cannot tell us why we allow them to grow so large and be led by so few. So we need to know why large societies of people in their millions or even billions have been useful when our pattern and our instincts throughout our history have been to live in small tribal societies. The answers will follow from the other two characteristics of these self-organizing systems mentioned earlier. One is that they can often become more efficient as they grow larger; the other is that they frequently acquire smaller structures within the larger whole.