by Mark Pagel
Vehicles—the individual amoeba in the case we have been discussing—are just the ways that genes act on the outside world to get themselves transmitted. The tower-building amoebae each carry a copy of a gene we can call the altruism gene. That gene, by causing a disposition to build a tower, is more likely to get itself replicated than a gene for remaining solitary, because the solitary amoeba will find itself alone on the forest floor. The advantage to the tower-building gene is slight, but it is better than the solitary choice. This is true even if some or even most of the individual amoebae in which that altruism gene resides die in spite of building the tower. The key point is this: the death of these amoebae promotes copies of this same gene that reside in the other amoebae in the stalk, even though in every other respect those others are not relatives, and could even be “strangers.”
Once we understand how the amoebae’s altruism works, the problem of getting altruism to evolve seems easy to solve. But the real challenge of making altruism work lies in coming up with some way that altruists can identify and then associate with other altruists, and thereby exclude those who lack the altruistic gene. How can I possibly know whether, if I help you, you won’t take my help and run? The social amoebae solve this problem by building the shared multicellular body or vehicle, the carpet that eventually forms the tower. The mere presence of another amoeba in the carpet automatically identifies it as one that carries the altruistic disposition to build a tower. The tower is itself, then, the collection of “like-minded individuals.”
Geneticists would describe the tower-building social amoebae as related to each other at a single locus. This is just a technical term for saying that at a single place in their genomes these amoebae share identical versions of the altruism or tower-building gene (as a comparison, parents and their offspring are normally related at 50 percent of their many thousands of genetic loci). It is extraordinary that a single gene can produce such profound effects against the background of all the amoeba’s other genes, but it can do so because building the tower benefits not just the gene for that disposition but all of these other genes. Those genes have no reason to oppose the building of the tower, even though for most of them the fate is death, because they can do no better than try their luck in the tower. The towers align individual with group interest—the amoebae have a shared fate—and so what might seem like foolish and gullible behavior is really their best bet for getting transmitted into a future generation of amoebae.
We set out in this chapter to understand a puzzling side of our nature—our tendency to help others, even when that help might not be directly reciprocated. If this altruism extended no further than to holding doors for people or giving up seats on trains, we might be tempted to dismiss it as just a charming side of our nature, although even doing that would simply raise the question of why we have evolved minds that find helping others an attractive thing to do—don’t expect this of an orang-utan or a gorilla. But we’ve seen that our behaviors go well beyond this, including risking our health and well-being or even sometimes giving our lives in war. That surely cannot just be a charming side of our nature; or if it is, we need to know how, in a Darwinian world in which the fittest survive, people willing to give their survival away can have prospered.
But if our journey into the details of amoebae sociality has done its work, you will be able to see the answer in the reflection of our cultural survival vehicles in their towers. For at least the last 160,000 to 200,000 years humans have resided in small, close-knit cultural societies that develop strong identities, often around their common language, and restrict the flow of people, ideas, and technology. The amoebae show us that these are just the behaviors that can favor the evolution and spread of the sort of ultra-sociality that makes our species so puzzling, because they create the conditions that allow altruists to surround themselves with other altruists. Then, something of a mutual aid society arises in which dispositions toward costly acts can more than pay their way because these other altruists are just as likely to help you, as you are to help them. As a result, everyone is better off than had they tried to go it alone, just as a solitary amoeba has little chance on its own.
What form might these dispositions take in our species? Humans seem to be equipped with emotions that encourage us to treat others in our societies as if they were “honorary relatives.” This is more than just a metaphor: we seem to practice a special and limited form of nepotism in which—just like the amoebae—we target our aid toward others who might not be related to us save for the fact that they are members of the same cultural group. Our nepotism is “special” and “limited” because our helpful emotions on the one hand, and prejudicial ones on the other, might be based on being related to these other members of our societies at just a single locus among our thousands of other genes. That single locus is the helping gene, and it would have spread in our evolutionary past, just as it has in the amoebae, by identifying others who carry copies of that gene and then helping them. For instance, the gene might simply code for an emotion that disposes people to be friendly toward those they perceive to be members of their societies.
In fact, nearly everyone will have experienced the vivid and controlling emotions that get us to favor members of our own societies over members of other societies for the simple reason that they are members of our societies. Maybe it is the feeling you get at a sports event, or hearing of your country’s troops in battle, or when your country is attacked by terrorists. We call these emotions “nationalism” or “patriotism,” or when directed against people from other groups, “jingoism,” “bigotry,” “xenophobia,” or “prejudice.” Most of us probably have no idea where these feelings come from; they appear spontaneously, they are visceral in nature, and they are alarmingly easy to teach to the young. They can also direct some of our most poignant and some of our most repugnant actions, and this leads us to believe they have played significant roles in our history in promoting our cultural survival vehicles, and more to the point, ourselves.
It might seem incredible that some of our most profound actions as a species could be based on such a simple mechanism, but we must take seriously the possibility that the nature of our cultural survival vehicles evolved because it creates the conditions that make our peculiar and yet powerful kind of altruism possible, and this is why they have been such formidable vehicles of our success. As we saw with the amoebae, even a single locus is enough to motivate costly ultra-social actions when cooperation serves all of our genes’ interests and not just the gene for cooperation. Next time you feel that warm nationalistic pride at the sound of your national anthem or the news of one of your country’s soldiers’ valor, think of the amoebae!
Still, maybe this is just a fanciful story in which our similarities to the amoebae are merely coincidental, and not of great significance. So before we are willing to accept that we are just jumped-up social amoebae with jingoistic tendencies, we want to find that this explanation somehow fits with other sides of our behavior. It is easy to say that the amoebae surround themselves with like-minded individuals because the mere presence of an amoeba in the tower means it carries the tower-building gene, and it is the act of building the tower that is altruistic and normally self-sacrificial. But it is not so easy for us. Someone’s mere presence in your society might not tell you anything about whether they share your altruistic dispositions. So we are forced to look for more than mere presence, and this might be why as a species we are so sensitive to cues of a shared cultural history, and so eager to create them. All those shared beliefs, customs, religious systems, languages, accents, rituals, songs, styles of dress, and mannerisms are the cues we instinctively and subconsciously use to assess our cultural relatedness to others. Our societies’ tendency throughout history to restrict the movement of people and ideas, and to develop strong identities around their languages and cultures, makes these cues more reliable.
The search for shared history can take powerful, dangerous, and even amusing turns, but it is ne
ver dull, and always revealing of our nature. I do not know whether it is true but I have heard it said of the “troubles” between Protestants and Catholics in Northern Ireland that Catholic youths upon encountering strangers would often ask them to recite the catechism as a way to determine if these strangers were fellow Catholics. Failure to get it right could mean a severe beating, or worse. I was once selling a house and it emerged that a person interested in it had attended the same university as me, although at a different time. I am sure this helped clinch the sale. In 1993, the then Welsh secretary (a position that at that time was a little like a governor general sent from London to oversee the running of a far-flung nation) was a man called John Redwood, and a member of the ruling Tory government. Redwood was prone to controversy, but his most famous gaffe came at a public meeting in Wales at which everyone sang the Welsh anthem. Redwood didn’t know the words, but aware this would offend the Welsh, he attempted to mime them. His strangely animated attempt was caught on camera and Redwood was broadcast to the nation looking like a marionette on the end of its puppeteer’s strings. At America’s Super Bowl in 2011 Christina Aguilera lost her way singing “The Star-Spangled Banner” and suffered weeks of abuse on the Internet. Ask any Briton what “LBW” means and they are likely to know, but it is doubtful that a visiting American would. Someone from America is likely to know what “RBI” means, but it is doubtful a British person will (hint: they are both related to sports).
I use some of these examples whimsically, but that is not to say the emotions that accompany them are mild or indifferent. Our special and limited form of cultural nepotism can even produce a disposition toward self-sacrifice that is eerily like that of the social amoebae. The journalist Sebastian Junger in his book War describes the experiences of a small platoon of U.S. soldiers in a remote, brutal, and violent region of Afghanistan known as the Korangal Valley. Junger spent time embedded with these men, who were on their own, with few amenities, ramshackle shelters, almost completely cut off at any given time from outside aid, and almost constantly under attack from deadly guerrilla forces. The men knew their fates rested on how well they performed together as a fighting force, and Junger came to realize that at the core of the platoon was a commitment on the part of each of the men to sacrifice his life for the others in battle.
It is tempting to romanticize such a commitment as the expression of noble heroes willing to die for their comrades, and this is the popular image of war films and national propaganda. But we have to ask ourselves how such dispositions could ever become widespread when for every noble hero there are many others of less noble disposition whose genes survive at the hero’s expense. We saw that the solution to this problem lies in recognizing that a disposition toward self-sacrifice can evolve so long as those who share it can identify each other. Then the deaths of some copies of the genes carrying this disposition help other copies of those genes to survive. Weirdly, a tendency to give your life can be adaptive to the gene that causes that disposition by virtue of promoting copies of itself that reside in others. Put more bluntly, your disposition toward self-sacrifice can be beneficial to you so long as you can surround yourself with like-minded people, because one of those people could save your life.
For many soldiers, one of the most disabling fears is the thought of being wounded and left to die, or of being captured and tortured. It can cause soldiers to hold back and not take chances. And yet, it is one of the tenets of small-scale battle that the group that escalates to violence most quickly often comes out on top. Junger describes how the men’s commitments to each other reduced their fears, and allowed them to fight more confidently. This meant the platoon was more likely to be triumphant in battle. And so, remarkably, the men were individually more likely to survive when they were all prepared to die for each other. This is not to say that anyone had a good chance of surviving, just a better one when they all pulled together. Holding back is not an option because anyone who shows signs of wavering in their commitment knows they will be left alone on the battlefield, where they would be almost certain to die. Generals know that groups of men who fight together are more likely to survive, and this is why armies spend so much time drilling these instincts into combat troops. But it might just be true that the dispositions to behave this way are already a deep part of our psychology.
A willingness to die in battle—or at least some sort of disposition for it—might reside to a greater or lesser degree in all of us as an emotion that draws on the same kinds of motivations that get us to protect our own families, although here the group assumes the role of the family. It might indeed be this part of our makeup that responds to real threats, but that can also be exploited by propagandists to produce Kamikaze-like or other suicidal behaviors. It is certainly relevant to this discussion that the political narrative that is offered up to justify such acts is normally one of intergroup conflict and great honor bestowed on one’s family. The act of suicide then becomes a way that one set of genes or ideas promotes others like itself by killing off ones that compete with it. Imagine what havoc a suicide bomber amoeba could do that broke away from its tower and somehow joined and then destroyed a competing tower, perhaps by releasing a poison. Its death would promote large numbers of copies of its altruism gene in the others back in its tower. The psychology of suicide bombers could be just this simple and cold-blooded, derived ultimately from our special and limited form of cultural nepotism.
Taking a step back, our more general tendencies to help others in our groups at some expense to ourselves should not be taken as evidence that we are “nice” or robotically dedicated to our groups. We are nice, but we should recognize this as an emotion that encourages us to cooperate, because cooperation pays individual—not just group—dividends. Indeed, our social nepotism, being based on just a single locus, is an emotion that is easily overrun by the cacophony of our other genes when their interests might be better served by selfishness. We can be cooperative and collaborative on the one hand, opportunistic, calculating, and selfish on the other, even toward members of our own groups. This is the unavoidable tension of group living: even with shared fates and shared purpose, what is best for your group can conflict with what is best for you. Soldiers in combat platoons, for instance, know that their colleagues will become less helpful near the end of their tours. When soldiers have fewer than thirty days remaining on their tours, they are called “short timers” or just “short,” as if to acknowledge that they have shifted out of the mutual aid society.
In a less deadly situation, the Tour de France bicycle race covers around 2,000 miles in a series of long stages spread out over several weeks. During a race a small group of riders might try to lead what is called a “breakaway,” riding off to the front of the main pack of riders. The riders in this small group must then work together, taking turns to ride in the lead, the rest saving energy by riding in the slipstream behind the lead rider. Every time a rider takes the lead, he is sacrificing some of his endurance, and this benefits all of the other riders. But it is a sacrifice that each of them must make to have any chance of staying ahead of the larger pack. On the other hand, cyclists in the breakaway pack will often try to do less than their share, and the pack will sometimes swerve and veer to try to shake them off. But it is when the race nears the finish line that the riders are clearly revealed not as selfless altruists but as self-interested competitors. If this breakaway group has managed to stay ahead of the larger pack behind them, the mutual altruism now unravels, the riders break ranks and sprint to the line, doing everything they can to beat those they have been helping.
Even the social amoebae’s sociality turns out to be shrewd and calculating. The outwardly serene towers of cooperating altruists conceal a society of competing strains for which making the tower is an act draped with suspicion and the potential for duplicity and manipulation. The tower provides only one route into the future, but it is open to whichever amoebae can get to the top first. Some strains of related amoebae within the stalk
cheat, advancing more of their members into this privileged collection of spores. Even before the tower is constructed, a carpet made up of many different strains moves more slowly across the forest floor than those composed of a single strain or of just a few. The delays arise from conflicts and jostling over desirable positions in the moving mass, just as the selfish riders in the breakaway packs ultimately slow their escape from the larger pack behind them.
Before leaving this discussion of how our altruism toward members of our societies might have evolved, I want to point out how the principle of identifying like-minded others invades another part of our lives: it is the same principle that governs our altruistic dispositions to favor our actual relatives, not just our honorary ones. Our nationalism really is a special case of a disposition to protect “our own.” Relatives, by definition, share many of their genes, so they are also likely to share any disposition that someone might have to “help relatives.” Surrounding yourself with relatives makes it likely you will receive as well as dispense benefits. There is nothing special about relatives, then, at least not from an evolutionary point of view, except that our relatives share many of their genes with us.
This weight of shared genes is why our familial nepotistic emotions are so strong—many genes are pulling in the same direction. In fact, the arbitrariness of the disposition we have toward relatives is revealed when we realize that we don’t really know who our relatives are—we merely assume they are the people around us in early life. This rule can go wrong, as when infants are mistakenly assigned to parents other than their own in hospital, but then reared normally with no one knowing. But this just proves that as we don’t really know who our relatives are, we use a rule of thumb. And that rule of thumb has worked well throughout our evolutionary past as a means of identifying people who are likely to share genes and hence our altruistic dispositions. Similar rules of thumb govern our dispositions to help other members of our societies.