by Oren Harman
If in a gene’s-eye view individuals are “vehicles,” the genes within the body saddled together as if on the very same boat, then a multilevel approach showing that groups are vehicles, too, can be translated into a gene’s-eye view model.24 Everything depends on whether the right conditions render individuals in a group akin to genes within a body, if “mechanisms of nonrandom assortment,” in other words, do in fact really exist. Relatedness can be one such mechanism, but it needn’t be the only one. Goodness depends on association, not necessarily family.25
It took him some time, but Hamilton began to grasp this after the cryptic phone conversation with George (“I thought you’d see that,” George told him when he finally came around). Suddenly Maynard Smith’s 1964 Nature article attacking Wynne-Edwards, the one that had made Hamilton so mad, didn’t look so unequivocal: Sharply distinguishing between kin selection and group selection, after all, no longer seemed always to the point.26 Hamilton made this clear in a paper he wrote in 1975 showing how the evolution of altruism between relatives is just an instance of group selection rather than an alternative explanation for an “apparent” altruism. It was the first application of George’s full covariance equation to an evolutionary problem.27
Not only kin selection but games of reciprocation, too, could now be viewed from an entirely new angle. If two hamadryas baboons grooming each other are playing a kind of prisoner’s dilemma they can easily be defined as a group. Clearly if one is an altruist and the other a free rider, the free rider will always win a benefit without paying any cost, and the altruist will always pay a cost without winning any benefit: Within the “group” it pays to be selfish. But what happens if the pair is compared with a second “group” made up of two altruistic baboons that groom each other loyally? Now, suddenly, selfishness becomes an impediment, for group B will be cleaner on average than group A, and therefore healthier and more likely to sire more off spring. The question then becomes whether between-individual/within-group forces are as strong as between-group/within-population ones. If association between the baboons is random, then they will be, and selfishness will beat out altruism. But if association is not random—if altruists, say, can choose to unite and stick together, leaving selfish types to pair vacuously with one another—altruistic genes enhancing grooming behavior will be able to evolve.28
Amazingly, Hamilton’s paper fell on deaf ears. Even though George had succeeded in changing his mind about group selection, and even though, starting in the late seventies, Hamilton began to be referred to by many as the greatest Darwinian since Darwin and to win every possible accolade, group selection remained under the shadow of the gene’s-eye point of view. If group selection exists in theory, most people said, it is too weak a force to play a role in nature. Into the eighties and nineties, and into the twenty-first century, theorists like Sloan Wilson continued to speak, frustrated, to those who would not listen.29
Slowly this is beginning to change.30 In 1981 Hamilton’s female-biased sex-ratio paper was exposed for what it really was—an instance of the test George Williams had asked for, showing group selection at work.31 A further oft-cited example, which Lewontin caught on to very early, involves the virulence of pathogens: If evolution acts on each single pathogen within a host, a “race” will begin between the pathogen and the host’s immune system, and the more hypervirulent the individual viruses the greater the chance they will all perish together with the host. On the other hand, if selection works on the entire virus population, attenuating it somewhat, there is a greater chance that the host will come into contact with other potential hosts (since not incapacitated or dead), and therefore a greater chance for the virus population to move on and survive. Just such an example was occurring in Australia: A virus, Myxoma, was introduced in the late sixties by its department of agriculture to help subdue a rabbit population wreaking havoc and growing dangerously out of control. At first the virus was devastating, but soon it began to attenuate. Lewontin explained:
When rabbits from the wild were tested against laboratory strains of virus, it was found that the rabbits had become resistant, as would be expected from simple individual selection. However, when virus recovered from the wild was tested against laboratory rabbits, it was discovered that the virus had become less virulent, which cannot be explained by individual selection.32
In fact group selection even emerged as a clinical concept, since hospital procedures and public health practices can be employed to favor the evolution of low-virulence strains. This became known as “Darwinian medicine,” and George Williams himself emerged as a pioneer late in his career.33 Slowly but surely further examples began to surface.34 And while group selection remains hotly contested, and good experimental examples are still few and far between, there’s no arguing that it’s making a comeback, at the very least in theory.35 Today even the entomologist Edward O. Wilson, whose 1975 book Sociobiology was a central pillar of the gene’s-eye-view approach, has come to believe that selection works at different levels. “Superorganisms” like bee and ant communities are literally giant vehicles, and the altruism they foster, Allee and Emerson would have been glad to know, is in that sense genuine and real.36
The possibility of selection at many levels, of course, makes the covariance equation all the more important. And so, drawn from the closet, dusted, and sparkled, the “Price equation,” as it has become known, is increasingly gaining new life. Theorists, among them notably Steven Frank, Alan Grafen, and the philosopher Samir Okasha, are finally joining in Hamilton’s enchantment, showing just how powerful a tool George invented and building further on its foundations.37 Ben Kerr and Peter Godfrey-Smith have recently even contributed a small improvent, adding a second covariance on the right hand side of the equation to make the causal structure more symmetrical and therefore more general, a development Price himself would undoubtedly very much have liked.38 Still, like any tautology, it’s sometimes unclear whether the Price equation is valuably invaluable or invaluably valuable: to really explain the natural world, it’s clear, the pristine mathematical beauty of the equation needs to be filled with the messiness of biology.39 But if the Price equation is better for framing a problem than for figuring out its messy biological details, it remains a crucial tool for understanding evolution in structured populations, where interdependence is just as important as either dependence or independence. Its generality means that it can be applied to evolution not only of genes but also to other forms of nongenetic evolution, based on epigenetic or behavioral inheritance. Alongside its ability to represent selection working on different levels simultaneously, this is a major, if still untapped, attribute. Besides altruism, the Price equation has already proved useful in attacking problems as diverse as reproductive value, evolutionary epidemiology, genetic programs, human cultural evolution, rogue genes, meiotic drive, biodiversity, and ecology. And the more we think of it the more it stands a chance to help us understand many other problems.40
Hindsight is a wise master. Having thrown down the rope of game theory, it’s now apparent, George Price helped others scale Mount Modern-Evolutionary-Biology with a stamina and strength that have proved enduring. But even more important, by providing the penetrating spectacles of covariance through which to measure all other ropes, he has helped us see more clearly than ever before that we are all climbing the very same mountain. It’s a legacy that will continue to transform the view of what Darwin called the “entangled bank,” a dramatically exciting window into the complexity and grandeur of life.41
They could hardly have imagined it when they met behind the curtain at the Belasco Theatre, but William Edison “Isak” Price and Alice “Clara” Avery would have much to be proud of in their son.
What about altruism in humans: Is any of this relevant to us?
Return to the hamadryas baboons playing a prisoner’s dilemma. Imagine first that each baboon is either altruistic or selfish by no fault of its own: Each is born the way it is, and can no more change its nature than a v
egetable become a fruit. But imagine further that each baboon has both capacities and can begin to choose whether it wants to be a Good Samaritan or a cheat. Suddenly we are in a completely new game: We have entered the world of mind.
It was Trivers who saw where this was heading. If cooperation and ultimately altruism are games of reciprocal good faith, what better way to police the system than to be able to detect deceit? Benevolence, he reasoned, requires a strong sense of justice, because a sense of justice is necessary in order to appreciate dishonesty. Over evolutionary time, and beginning with animals, a genuine instinct of fairness would have been born out of the need to distinguish the trustworthy from the swindlers. This has been demonstrated in recent experiments with capuchin monkeys: Experimenters rewarded monkeys with sweet grapes when the monkey handed them a stone, but when the monkeys were divided into two groups, one of which was handed grapes in return for the rocks and the other much less attractive cucumbers, many of the monkeys in the second group would not accept the offer. In fact the sense of unfairness could even be magnified: When, in return for their rocky offering monkeys were given absolutely nothing, some began pelting the experimenters with stones in outrage. Both our human sense of right and wrong and our discretion over when and where to use it are, it seems, legacies of natural selection.42
This may help to explain why we are so good at detecting cheats. A number of neat experimental designs suggest that this betrays a human cognitive bias: We are better at solving logical riddles that have to do with exposing shysters in real-life situations than we are solving the very same puzzles presented in the abstract. Whether detecting cheats also requires a system of punishment is a question that is argued. While some find punishment requisite for cooperation, others claim that it’s effective, but only for establishing dominance. True egalitarian cooperation, on the other hand, is best served by withholding recrimination: At least when it comes to peers (as opposed to the state), taking the law into your own hands is unprofitable.43
Whether punishment is necessary or not, it’s clear that people often cooperate altruistically even when they have absolutely nothing to gain: The classical economic assumptions of self-interest cannot explain the richness of human behavior, Adam Smith’s long shadow notwithstanding.44 This may not be all that surprising if one considers how valuable regard, and its subtler cousin, self-regard, is to human beings. But why should this be so?
Following in Trivers’s footsteps, the economist Robert Frank proposed that it all comes down to trust. To do well in life, our simian and hunter-gatherer ancestors needed to forsake the short-term temptation of self-interest, since they lived in small, mutually dependent groups. Emotions, or what used to be called “moral sentiments,” helped to ease the retreat from egoism by establishing commitment (“I love you and won’t leave you”) and eliciting reciprocity (“I love you, love me back!”). Since in evolutionary terms life is a game in which one seeks trusted partners to play with, emotions that trigger loyalty and altruism (even irrational ones) are adaptations for regulating behavior. According to this view we have a genuine conscience underlying our emotional repertoire in order to help us join hands with other conscientious sorts to everyone’s mutual advantage.45
But the logic is tricky. The possibility of deceit raises the probability of ever more subtle mechanisms for spotting deceit, which raises the probability for mechanisms of self-deceit. Trick yourself to trick another; what better way to conceal true intentions? This in fact seems rampant in unsuspecting man: Ask a hundred people whether they are above average in intelligence, or beauty or kindness or virtue, and considerably more than fifty, hand on heart, will tell you that they are. Still, if an arms race was put in place in evolution between cheaters and detectors, perhaps the result has ultimately been felicitous: After all, the best way to seem trustworthy and giving is to actually be trustworthy and giving.46
Which is it, then: pure genuine selflessness or an egoism so cunning that even the trickster is tricked? Some argue that the genuineness of goodness can be demonstrated scientifically, though their arguments seem really quite feeble. The strongest case that can be made for pure unsullied selflessness is that it is just as plausible as unadulterated egoism. Proponents call this “pluralism,” but in truth it is more of an admonition: There are questions that, however much we’d like it to, science simply cannot solve.47
Whether goodness is genuine or not, it was the father of the theory of evolution by natural selection who instructed that the moral sense has natural foundations. “Mr J.S. Mill speaks, in his celebrated work, ‘Utilitarianism,’” Darwin wrote in The Descent of Man in 1871,
of the social feelings as a “powerful natural sentiment,” and as “the natural basis of sentiment for utilitarian morality.”…But…he also remarks, “…the moral feelings are not innate, but acquired.” It is with hesitation that I venture to differ from so profound a thinker, but it can hardly be disputed that the social feelings are instinctive or innate in the lower animals; and why should they not be so in man?…[Several thinkers] believe that the moral sense is acquired by each individual during its lifetime. On the general theory of evolution this is at least extremely improbable. The ignoring of all mental qualities will, as it seems to me, be hereafter judged as a most serious blemish in the works of Mr. Mill.48
In private, rhetorical deference could duly be abandoned: “He who understands baboon,” Darwin scribbled in his personal notebook years before, “would do more towards metaphysics than Locke.” The mind had been crafted by millions of years of evolution. If man wanted to comprehend his own morality, he’d need to take a careful look back at the animals.
Everyone says humans are special, and, undoubtedly, this is so. Even if each and every species is idiosyncratic, if uniqueness is really not unique, however we like to spin it, our culture does set us apart.49 Hamilton saw that this meant that group selection might play an even more central role in humans: The kind of cohesiveness borne by living in small hunter-gatherer groups and developing language might help solve the “free-rider” problem and would only have been strengthened by religion and lore. This left him cold: Group selection bumping whatever the opposite of altruism is to the next level was nothing to gain any solace from. For in order for true goodness to be born, a ruthless rival to the group was mandatory. This would both foster xenophobia between groups and necessitate a closing of the ranks within, a realization that led Trivers to dub Hamilton’s 1975 study his “Fascist paper.”50
It’s a sobering thought, but it needn’t always be true. A recent study in rats showed that the more a rat benefits from the altruism of a stranger rat, the more he will later act benevolently towards stranger rats himself.51 This happened in a laboratory, in rats that were trained by humans to pull a lever that released food for a stranger rat in another cage—perhaps not the best approximation of what happens in nature. But we humans constantly find ourselves in situations where complete strangers need our help. In fact the notion that as egalitarian morality spreads through education and culture to an ever-greater number of people, the costs of altruism are reduced may mean that we have developed a unique capacity for altruism. It’s true: History continues to serve up a litany of factious wars over religious and political influence.52 But this doesn’t mean things can’t change. Cheap airfare, integrated markets, the Worldwide Web, and the extinction rate of languages are just a few of the harbingers of our increasing interdependence. And even if globalism fails or infinitely worse—the promise of universal tranquillity crashes—something else may end up uniting us. A classic Hardin “tragedy of the commons,” the threat of a degrading environment, could graduate mankind to a higher level. And if Earth can serve as a genuine “vehicle,” then the environment will be a proxy for a ruthless enemy. Short of recognizing the inherent goodness in universality and peace, coming together to protect our planet may prove a saving grace for a still-fractured humanity. In the end it may even lead to an expansion of our circle of morality to other creature
s besides ourselves.53
These are grand affairs. What direction history takes is known only to prophets and fools, and from the dawn of time distinguishing between the two has been impossible. Increasingly, however, science is training its gaze inward, to the brain, in search of clues to the origin of altruism. The neuroscientists Jorge Moll and Jordan Grafman placed volunteers in a functional MRI unit and asked them to imagine either donating a sum of money to charity or keeping it to themselves. They found that thoughts of generosity activated a primitive part of the brain that lights up with reference to food and to sex, a result interpreted by them to mean that altruism is as hard wired as our most basic functions.54 The psychologist Marc Hauser agrees. His research shows that all over the world people process ethical dilemmas in very similar ways, suggesting that the capacity for moral judgment, like language, should be thought of as intrinsic to our nature rather than a product of our culture. It is a well-documented fact that injuries to particular parts of the brain result in patients who seem to have lost their moral sense: Perfectly intelligent otherwise, they remain unable to tell right from wrong.55
But science is going further. In the most reductionist attempts to date to locate a “moral sense,” researchers have begun searching for genes for goodness: A team led by the psychologist Ariel Knafo, the geneticist Richard Ebstein, and their graduate student Salomon Israel gave fifty shekels to two hundred students and asked each of them to play what is called a dictator game: The person with the money, the “dictator,” must make a one-shot, nonreciprocated decision on how much of his pot to share with an anonymous “recipient.” Not surprisingly there is quite a bit of variation: some split their loot judiciously down the middle, others selfishly keep it to themselves, still others give most of the money away. What the researchers found when they genotyped the students was that there is a significant correlation between the degree of giving and the length of a tiny DNA microsatellite in and around a gene encoding for a receptor of the neurotransmitter oxytocin in the brain. The same was true for a related neurotransmitter called vasopressin. According to these studies, and however incredible, altruism is literally in (and around) our genes.56