The Price of Altruism Read online

  Walking nature’s trails, Hamilton was once again where he wanted to be. It would take nine months to resubmit the corrected manuscript, “The Genetical Evolution of Social Behavior, Parts I and II.” Oblivious to the world, he did not know that in that space of time John Maynard Smith, citing only the shorter American Naturalist article, wrote and published “Kin Selection and Group Selection,” giving “inclusive fitness” its catchy name. Nor, of course, did he know that Maynard Smith had been the anonymous reviewer responsible for its delay. When he did find out, it would ignite in his humble soul a feeling it rarely countenanced. But this was still far off in the future. “Very probably,” he later wrote of the present,

  the sun of the day that saw my paper going into the post from JTB…would have seen me weaving my old American jeep between the corrugations, stones, and potholes of the Belém-Brasilia road…. At midday it would have blazed near vertically on the top of my head as I stopped at the roadside and collected wasps from some nest; later at sunset, if still able to pierce the haze, it would have seen me and my Brazilian companion…slinging our hammocks between low cerrado trees not far from the stony or sandy piste where occasional lorries still groaned on into the night. For sure, both that day and that night I was blissfully untroubled about the finer points of measuring relatedness.44

  No one hated group selection more than George Williams. A lanky American fish specialist with the beard-but-no-mustache look of what some described as an Easter Island statue, he was determined to fight Wynne-Edwards. As a student he’d heard a talk by Emerson: Death, the Chicago man argued, was an adaptation for the good of the group. Williams wouldn’t believe it. Organisms dying just to “get out of the way”? That couldn’t be right. “If this was evolutionary biology,” he said to himself, “I wanted to do something else—like car insurance.”45

  Across the Atlantic in Oxford, meanwhile, Lack was doing his damnedest to put the notion of the “greater good” to rest. There was no reason to assume with Wynne-Edwards that birds restrain their reproduction to strengthen the group. If a mother bird produced a smaller clutch of eggs, it wasn’t because she was in cahoots with all the other mothers to lessen the number of progeny. On the contrary, if resources were slim that year, it made perfect sense to sire fewer younglings in order to be able to care properly for those who were born: In a season of dearth, a mother might feed three goslings to health, whereas if there were seven all might die of hunger. No, natural selection didn’t fashion adaptations for the good of the group; always, inexorably, it was “looking out” for individuals.46

  It was 1966. Nine years earlier Williams had worked out a model, better than Wright’s, that revealed the conditions under which group selection might work.47 But like Maynard Smith he’d become convinced that while possible theoretically, it was improbable in nature. Lack was right: If behavior could be explained by selection working at different levels, there was no reason to choose the higher level over the simpler one. Walking Occam’s razor, the evolutionist should be guided by parsimony.

  However powerful a tool, though, parsimony was a matter of interpretation; it was difficult to settle unequivocally whether selection was working at the level of the individual or the group. What Williams really needed to kill group selection was a prediction that could generate a natural test. And he found what he was looking for buried in a paragraph in the pages of The Genetical Theory of Natural Selection.48

  Fisher had argued that sex ratios in any species should always evolve to an equal number of males and females. The reason was simple: A male born into a species with a female-biased sex ratio is at an advantage, since he has more mating opportunities than a female. If genes determine sex, then in a population with more females, the male-making gene will be favored by natural selection. Eventually the frequency of that gene will reach a point where the sex ratio of the species is now male-biased, whereupon its alternative, a gene promoting the production of females, will be favored. The dancing dialectic would ensure a symmetry of sexes: The wisdom of selection fashions males and females one-to-one.

  Even though he didn’t know it, Fisher was playing a game, just like the ones John von Neumann loved. Whether a mother should produce a son or a daughter, after all, depended on what other mothers were doing—the requisite condition for the application of game theory. But beyond the convergence of economics and biology, what Williams now saw was that Fisher had done a blessed service: Figuring out the logic of the symmetry of the sexes, he’d delivered the deathblow to the notion of the “greater good.”

  Here is why: Imagine a mother parrot mating and then flying off alone to a deserted island in the middle of the sea. Imagine that she lays 10 eggs, half of which hatch into males, the other half into females, and imagine that her daughters do the same. What will happen? The population will grow rather quickly: From 10 in the first generation, it will balloon into 50 in the next (25 females and 25 males), 250 in the generation after that (125 of each sex), and so on.49

  But what if the mother parrot lays 10 eggs that hatch into 9 females and just 1 male, and her daughters do the same: How then would the population grow? In the first generation, as before, there would be 10 parrots (9 females and one male). But in the next generation there would be 90 (81 females and 9 males) and in the one after that 810 (729 females and 81 males). Compared with a 1:1 sex ratio, a female-biased ratio would run much faster. Before long the island would be teeming with parrots.

  But there was a twist. Even though siring more females would benefit the growing group, it would actually reduce the individual fitness of the mothers who did so. Imagine two mother parrots arriving on the island: Linda sticking to the 1:1 sex ratio, Barbara to the 9:1. Together they will produce 20 offspring in the first generation: 5 + 9 = 14 females added to 5 + 1 = 6 males. When these off spring mate among one another, while each female continues to lay 10 new eggs, the average male sires 23 children (140 divided by 6), since he fathers the offspring of more than 2 females. The results for Linda and Barbara are surprising: After three generations, Linda, who stuck to the slower 1:1 sex ratio but had more males, will have 165 grand-offspring whereas Barbara, who went for the 9:1, will have only 113.

  When it came to the sex ratio there was a conflict between community and individual: If the group counts, “altruistic” Barbara is the winner, but if the individual is selection’s client, “selfish” Linda prevails. Wynne-Edwards had shown that in times of dearth it is not always to the advantage of the population to breed as much as possible. But assuming sex ratio was an adaptation, when the times of dearth were over one would expect a switch to a female-biased sex ratio. Scouring the literature, Williams saw that this never happened—not in flies, not in pigs or rabbits, not even in humans. Over time and across all vagaries the 1:1 sex ratio remained stable—the very prediction that selection working to maximize individual fitness required.

  It was a mortal blow to the doctrine of the “greater good.” Practically overnight, Adaptation and Natural Selection became a classic and group selection a theory to stay away from like the plague. Finally “Wynne” had been felled, though, like Sisyphus, he would keep on fighting his battle. Williams ended with a tip of the hat to Fisher: Beyond a doubt, fulmars and red grouse notwithstanding, natural selection produces adaptations optimizing individual fitness. “I am convinced,” he wrote triumphantly, “that it is the light and the way.”50

  Back from Brazil, Hamilton had news of his own: In countless species of ants, thrips, wasps, beetles, and mites there are extraordinary sex ratios, major departures from Fisher’s pristine one-to-one. Hamilton, unlike Fisher (and even Williams), would know: He had found them peeling back bark from capirona and kapok trees, stripping weeds of larvae beneath shallow jungle streams, and munching on figs with internal surprises. Mellitobia acasta was an example: A tiny parasitic wasp, its female lays her eggs inside the living pupae of bumblebees. When the eggs hatch they eat their way out of the pupa, but not before each female engages in sex with the sole male
, their only brother. After all, it makes sense for their mother to use the confined body of the pupa to lay as many female eggs as possible and only one male to inseminate them: Once they’ve been fertilized, they can fly away to lay their own eggs in another poor bumblebee pupa, while their exhausted brother and lover, the wingless male, wastes away in the abandoned cocoon.51

  By now Hamilton had a research position at Imperial College Field Station near Ascot, an institution eminent in the study of insect ecology. Around its rotten-wood grounds in Silwood Park, in the asphalt cracks of his cramped Berkshire home, and on walks in the royal forests around Windsor he discovered the Western European cousins of his Amazonian friends. Parasitism, he was learning, could get complicated—and fast: Sometimes two females laid their eggs in the same caterpillar or pupa, sometimes progeny dispersed and sometimes they didn’t; sometimes ruthless males, like “maniacal homicides armed with knives,” fought over amorous sisters to the death. Each situation changed the rules of fitness entirely. How would a miniature acasta know what precise proportion of male-to-female eggs to lay?

  To figure out himself what the answer should be, Hamilton journeyed into London many days to use the UCL computer center at Gordon Square. It wasn’t a pretty affair: Programming in the dinosaur FORTRAN language, which still preserved its nineteenth-century Hollerith punched-card six-space markings—“those once-useful claws that are now diminished to useless toe nails,”—Hamilton would queue along the old kitchen staff’s route to the basement, roll of five-punched tape ready in hand, watch as the technician set the toggles to guide the “magic monster” Mercury computer, walk across to collect the spaghetti-like tape spewing chatteringly out the far side, and rush to an adjacent room to view the results via a teletype. It was a far cry from sitting in front of a laptop.52

  But despite the hassle and beneath the natural complications, the teletypes disclosed a pristine river of logic. Whether you were an ant in a weevil egg, a wasp in a wild fig, or a mite inside your own mother, there always existed an optimal solution to the problem of the precise proportion of female to male eggs to lay. Hamilton called it the “unbeatable strategy,” and discovered to his great astonishment that, with no Mercury and toggles and teletype and FORTRAN, the little critters always found it on their own.

  It was mind-blowing. Mites “calculating” fractions as precise as 3/14ths? Hamilton was godless, but this was as close to faith as anything. Now, he knew, he’d discovered a powerful tool that would help to fathom nature’s wonders. Back when he was a student at Cambridge he had idly read von Neumann’s great book, never imagining that it might have anything to do with biology. But there was no mistaking that here was an evolutionary analog to the prisoner’s dilemma: Fitness was a “payoff,” the opposing sex-determining genes the “players.” In parasitic wasps and sex ratios he was dealing in the theory of games.53

  No one seemed to notice at the time that extraordinary sex ratios provided the very test that Williams had sought to apply to group selection.54 Hamilton himself contributed to the confusion: Extraordinary sex ratios couldn’t be an adaptation for the good of the population, he wrote, since even a tiny bit of outbreeding would destroy any “altruistic” genes.55 No, once again this was a family affair; small spaces like pupae, after all, were like isolated cottages. In line with the times, parasitic wasps were interpreted as just another nail in the coffin of the “greater good”: It was gene frequencies that were being maximized, after all, and they could only do it by manipulating the behavior of related individuals.

  Laying down his pencil, Hamilton might have smiled. First rB > C and now sex ratios: The mathematics of the “gene’s-eye-view” was turning biology into a “hard” predictive science. Fisher had been right: Selection was a mechanism for generating an exceedingly high degree of improbability; even altruistic behavior was fashioned by its unsentimental, ruthless cull. He ended his equation-filled article, in the grand natural-history tradition of humble cooperation, by thanking a Dr. Bevan “for information about bark beetles” and a Dr. Lewis “for information about thrips.”

  Group or Individual, Optimization or Chance: Where had true goodness come from? Wright and Haldane and Fisher had begun the work, uniting Darwin and Mendel, selection and genes, in a bold evolutionary synthesis. They had argued among themselves over the relative role of mutation, drift and selection, but their project had been one of foundation. Now, on the back of Wynne-Edwards and the “greater good,” younger men like John Maynard Smith, George Williams, and Bill Hamilton were penetrating further into Nature’s puzzles. Theirs had been a thought experiment as audacious as Einstein’s, only from the point of view of the gene rather than a man traveling on a beam of light. Finally, they thought, they were solving the mysteries of behavior.

  In the Amazonian jungle in 1964, Hamilton received a letter from a girlfriend in London. She was breaking up with him. That week in the forest he had met two Brazilian kids, Romilda and Godofredo. Alone and morose, he was having serious doubts whether he’d ever marry or have children of his own. Turning to their parents, he offered to educate and take care of them as a foster parent back in England.

  Now, four years later, his glum misgivings had proved premature. He was married to a wonderful woman, Christine, and thinking of starting a family. But a promise was a promise. The year after publishing “Extraordinary Sex Ratios” in Science he and Christine were back again in the forest and would be taking Romilda and Godofredo to Berkshire. Evolution hadn’t selected him to behave this way toward nonkin, he was now more than ever certain. But lying in his hammock listening to the beat of the wings of an iridescent dragonfly and a seriema pealing its dawn call like cracked bells from the hills, he knew it was in his lonely heart, still.56

  A letter from Alice Price to her son George, November 6, 1963

  No Easy Way

  In the spring of 1957 Senator Hubert Humphrey had introduced a bill offering income tax credit for tuition paid to institutions of higher learning. George wrote a letter of thanks. It was all about education, he thought, and the bill was a step in the right direction. Still, really, intervention was needed much earlier. Why not exempt the first six thousand dollars received for teaching in grade school? After all, the greatest weapon against the Soviets was undoubtedly the first-grade teacher. “I belong to the ‘as the twig is bent, the tree grows’ school,” George explained.1

  He had struck up a correspondence with his old senator from Minnesota, and there were further suggestions to help win the Cold War: Why not send every Russian two pairs of shoes if their government would free Hungary? Or ten million dollars worth of polio vaccine if the Hungarian police would stop torturing prisoners? Or what about radio messages broadcast in Russian extolling the advantages of butter over guns? And could the senator please send a copy of his “U.S. Foreign Policy and Disarmament” speech to Congress in April? And the hearings of the Johnson Preparedness Subcommittee? And had he seen the piece by Donald Harrington yesterday in the Times? “Of course! Why didn’t I think of that myself?”: an international court of law to help restrain the Chinese in Formosa. Could the senator perhaps “plant the idea tactfully within Mr. Dulles’s mind?” George would very much appreciate it.2

  The senator replied politely that he would welcome his advice and counsel. George’s views were “eminently sane,” the idea about creating a strong UN police force just along the lines he had imagined. Price’s overanxious manner might have struck the senator as somewhat odd, but his replies made George exceedingly proud. Nothing felt better than a man of stature recognizing his potential.

  Increasingly, writing popular science articles became the perfect vehicle for gaining notoriety. It was the journalist’s prerogative, after all, to get in touch with famous people. And so, between “The Physics of Bowling,” “U.S. Begins Search for Beings in Other Worlds,” and “What We’re Learning from Animals” (all for Popular Science Monthly), he drove to his old hero Claude Shannon’s home to write a profile on him for IBM’s mag
azine, THINK—the two “paddling around” his lake in “glorious” silence. Between “Achievements of American Science,” “The Real Threat from Red China” (government brainwashing), and “How to Hatch an Egghead” (motivate him), he contacted the Nobel laureate Hermann J. Muller, to ask his views about evolution on other planets. On each occasion the excuse developed into a conversation, with George trying his very best to impress. Muller, who was considered by many to be the greatest living geneticist, remembered “Science and the Supernatural” and complimented him on it; George replied with quotes from Poe and Keats, and his thoughts about people reading too much science fiction. Muller thanked him kindly, and the correspondence ended at that. It was a pattern: the brushup, the exchange, the titillation.3

  If IBM had been stupid enough not to hire him, George was not about to give up and roll over. On the strength of the piece in Life he had been offered a contract by Harper & Brothers, and was hard at work on a book now that he hoped would help to save the world.

  It was right about then that Skinner came along.

  Adored as a messiah and abhorred as a menace, Harvard professor Burrhus Frederic Skinner was the most influential psychologist in America. He had an elongated face and an unsettling smile. The leader of the “behaviorists,” who likened man to machine, he was reviled by Freudians and humanists. Some called him “totalitarian,” others “Orwellian” others thought his ideas man’s only hope.4

  George was intrigued. Early Christian thinkers thought it was the “soul” that set man apart from animal: God-given, immaterial, impalpable, otherworldly. But what if man were just an animal, firmly planted in the natural world? And what if men and animals were not all that different from machines?