Naturalist 25th Anniversary Edition

by Edward O. Wilson

  The optimistic prospect for sociobiology can be summarized briefly as follows. In spite of the phylogenetic remoteness of vertebrates and insects and the basic distinction between their respective personal and impersonal systems of communication, these two groups of animals have evolved social behaviors that are similar in degree of complexity and convergent in many important details. This fact conveys a special promise that sociobiology can eventually be derived from the first principles of population and behavioral biology and developed into a single, mature science. The discipline can then be expected to increase our understanding of the unique qualities of social behavior in animals as opposed to those of man.*

  Where might I go next? Originally I had no intention of extending my studies beyond the social insects. If honeybees are excluded for the moment—apiculture was in 1975 a major applied discipline unto itself, with hundreds of practitioners—the vertebrate animals, comprising fishes, amphibians, reptiles, and mammals, had at least ten times more zoologists attending to their behavior than was the case for insects. The mainstream journals of evolutionary biology tilted toward the natural history of the biggest animals, and vertebrates prevailed among the textbook case studies of ethology. Vertebrate behavior seemed too formidable a subject to enter from the direction of entomology. But I found out I was wrong. After probing a bit, talking with specialists, I had a revelation. Vertebrates weren’t difficult at all. Very few zoologists appeared to be aiming toward an integrated sociobiology of these animals, at least not with an emphasis on population biology or with the speed and directness that Hamilton and I and a few others had achieved for the social insects. With my inquiry expanding, I saw that entomology is a technically more difficult subject than vertebrate zoology, partly because insects are so much more diverse—750,000 known species versus 43,000 vertebrates—and partly because they seem so alien to Homo sapiens, the giant bipedal vertebrates who can see them clearly only through microscopes. They receive little attention in college curricula, and few students turn to them for a career. Not least, advanced insect societies are more complicated and variable than those of the nonhuman vertebrates. So I reasoned that it should be easier for an entomologist to learn about vertebrates than for a vertebrate zoologist to learn about insects.

  Once again I was roused by the amphetamine of ambition. Go ahead, I told myself, pull out all the stops. Organize all of sociobiology on the principles of population biology. I knew I was sentencing myself to a great deal more hard work. The Insect Societies had just consumed eighteen months. When added to my responsibilities at Harvard and ongoing research program in ant biology, the writing had pushed my work load up to eighty-hour weeks. Now I invested two more years, 1972 to 1974, in the equally punishing and still more massive new book, Sociobiology: The New Synthesis. Knowing where my capabilities lay, I chose the second of the two routes to success in science: breakthroughs for the extremely bright, syntheses for the driven.

  In fact the years spent writing the two syntheses were among the happiest of my life. In 1969 Larry Slobodkin invited me to join him in a summer ecology course at the Marine Biological Laboratory in Woods Hole, Massachusetts. In late June Renee, Cathy, and I journeyed to the small coastal village and moved into one of the cottages maintained by the MBL at Devil’s Lane. One mile away, at the end of a winding country road, sat the spectacular lighthouse on Nobska Point, and beyond the lighthouse hill Little Harbor, and yet farther out, across the sail-dotted sound, the vacation island of Martha’s Vineyard. Cathy, just then entering kindergarten age, fell in with a gang of other faculty youngsters. She and I also spent hours gazing at butterflies, birds, and, in the swamp behind our cottage, a colony of muskrats. In the late afternoons and evenings the three of us explored the southern reaches of Cape Cod by car. After lunch, outside class time, I took long runs over the Quissitt Hills along the coastal road to Falmouth. The rest of my free time I wrote, and read, and wrote. We continued to return to Wood’s Hole for another eighteen summers, through Cathy’s college years. It was a balanced life during that long period, deeply fulfilling.

  In the preparation of the vertebrate sections of Sociobiology, I was boosted by an exceptional quality of support resulting, I am inclined to think, from sheer good luck. Decisive parts of the bibliographic search and manuscript editing were conducted by Kathleen Horton, who had joined me in 1965 and acquired a high level of expertise in the difficult and sometimes arcane disciplines that feed into sociobiology. Nearly thirty years later, she continues this vital role across a broad range of biological subjects.

  Sarah Landry, then as now one of America’s best wildlife illustrators, was miraculously available in the early part of her career as I started work on my big books. She depicted animal societies with composites of animals in behavioral acts that could never be brought together in a single photograph. With a passion for accuracy, she went beyond the effort required for an ordinary book on animal behavior, traveling to zoos and aquaria to sketch captive animals and visiting herbaria to render in detail the plant species found in the natural habitats of the animal societies. To Sarah, the bushes among which a mountain gorilla foraged meant as much as the gorilla itself.

  My uneasiness about vertebrate zoologists subsided when I found that they were going to treat me as an ally rather than an intellectual poacher. I sold myself, honestly so, as their chronicler and friendly critic. Literally all with whom I communicated encouraged me to go forward. Many showered me with books, articles, and evaluations of the large literature.

  Nineteen seventy-four was one of the earliest years in which a critical mass of sociobiological theory could be assembled. Studies of important species such as the Florida scrub jay and whiptail wallaby were in their final stages. And new elements of theory continued to pour in. One of the new theoretical concepts destined to be most influential was the natural selection of parent-offspring conflict, originated by Robert Trivers of Harvard. Like Hamilton, Trivers attained the key concept as a graduate student; I had just finished serving on his Ph.D. review committee. Trivers both benefited and suffered from a case of manic-depressive syndrome (now cured). When he was up he was dazzling; when he was down he was terrifying. We came into contact only during the peaks. He would stride through my office door and sit down, oblivious or uncaring of the old Harvard custom of making appointments. Thereupon I figuratively fastened my seat belt and prepared for swift and rocky travel to some unknown destination. Then would come a flood of ideas, new information, and challenges, delivered in irony and merriment. Trivers and I were always on the verge of laughter, and we broke down continually as we switched from concept to gossip to joke and back to concept. Our science was advanced by hilarity. My own pleasure in these exchanges was tinged with a sense of psychological risk, as though testing a mind-altering and possibly dangerous drug. Nor could I just sit and listen to Trivers, and let his mental productions wash over me. It is my nature, my conceit if you wish, to try to match any person with whom I converse fact for fact, idea for idea, and never quit. This is the reason I get killed in the company of my friends Murray Gell-Mann and Steven Weinberg, Nobel laureates in physics, egocentric, supremely self-confident, and said to be competing for the title of World’s Smartest Human. Two or three hours with Trivers left me exhausted for the day.

  For five spectacular years, 1971 through 1974, Trivers blazed new paths in sociobiological theory. He generated a model of reciprocal altruism, by which humans and more intelligent animals evolve contract rules that reach beyond self-sacrifice based on kin selection. What is undoubtedly his most important contribution, the theory of the family, and especially its undergirding models of parent-offspring conflict, set the foundation for today’s substantial research enterprise on these subjects within behavioral biology. The selection pressures that bear on the evolution of nurturing, he pointed out, are different and sometimes opposite for parent and offspring. Shifting in direction and intensity as the young mature, these pressures account for youthful rebellion and family tensi
ons better than the more proximate, conventional explanations of personal maladjustment and stress. At the least, Trivers provided a plausible argument for the ultimate causation of conflict, which persists regardless of the day-to-day proximate stressing events that trigger it.

  It was Trivers who finally found the flaw in Hamilton’s argument. Then he fixed it in a way that lent kin selection even greater credence. The flaw is the following. So long as social hymenopterans—ants, bees, and wasps—raise an equal number of males and queens among the brood destined to start the next generation of colonies, there is (contrary to Hamilton) no advantage for sisters to behave toward one another with any unusual degree of altruism. As a result of haplodiploidy they share three-fourths of their genes with sisters and only one-fourth with brothers, instead of one-half with both sexes, which is the case in animals using ordinary modes of sex determination. The imbalance in the Hymenoptera would seem to favor the formation of female colonies: more of a worker’s genes will go into the next generation if she raises sisters instead of daughters. But, Trivers noted, if the haplodiploid ants, bees, and wasps rear equal numbers of sisters and brothers, they end up with an average relationship for all the offspring of one-half; canceling the apparent advantage. Mathematically, we can express this conclusion as follows:

  ½ (fraction of females) × ¾ (genes shared)

  + ½ (fraction of males) × ¼ (genes shared) = ½

  One-half of the genes shared on average is the same payoff as from the ordinary production of sons and daughters without haplodiploidy. Only if the workers can raise a higher percentage of sisters in the royal brood can they reap the larger rewards of altruism twisted by haplodiploidy. The best possible overall degree of relationship in the Hymenoptera is five-eighths, reached by investing three-fourths of the resources in sisters:

  ¾ (fraction of females) × ¾ (genes shared)

  + ¼ (fraction of males) × ¼ (genes shared) = ⅝

  Five-eighths beats one-half and gives the advantage to colonial existence, if all other conditions are equal. Subsequent studies showed that this is indeed approximately the ratio reared by ants. Somehow ant workers manage to obey the expectations of kin selection worked out in the heads of two zoologists.

  I meant Sociobiology: The New Synthesis to serve as a network of such theory, as a vade mecum, and, not least, as an encyclopedia. I covered all organisms that could even remotely be called social, from colonial bacteria and amoebae to troops of monkeys and other primates. I recognized four “pinnacles” of social evolution, groups of species whose societies were, first, independently derived in evolution, and second, complex or sophisticated in organization, and, finally, possessed of genetic structures and organizations differing radically from those of the others. The pinnacles are respectively the corals, siphonophores, and other invertebrates; social insects; the social vertebrates (especially the great apes and other Old World primates); and man. Yes, man; that is the word I used in 1975, before it became unacceptably sexist and still meant generic humanity, while it still exercised the same resonant monosyllabic authority as earth, moon, and sun.

  Perhaps I should have stopped at chimpanzees when I wrote the book. Many biologists wish I had. Even several of the critics said that Sociobiology would have been a great book if I had not added the final chapter, the one on human beings. Claude Lévi-Strauss, I was later reminded by his friend the historian Emmanuel Ladurie, judged the book to be 90 percent correct, which I took to mean true through the chimpanzees but not a line further.

  Still I did not hesitate to include Homo sapiens, because not to have done so would have been to omit a major part of biology. By reverse extension, I believed that biology must someday serve as part of the foundation of the social sciences. I saw nothing wrong with the nineteenth-century conception of the chain of disciplines, in which chemistry is obedient to but not totally subsumed by physics, biology is linked in the same way to chemistry and physics, and there is a final, similar connection between the social sciences and biology. Homo sapiens is after all a biological species. History did not begin 10,000 years ago in the villages of Anatolia and Jordan. It spans the 2 million years of the life of the genus Homo. Deep history—by which I mean biological history—made us what we are, no less than culture. Our basic anatomy and physiology and many of our elementary social behaviors are shared with the Old World nonhuman primates. Even our unique qualities, the tool-using hand with its bizarre opposing thumb and the capacity for swift language acquisition, have a genetic prescription and presumably a history of evolution by natural selection. It felt appropriate to use provocative language as I opened the final chapter of Sociobiology:

  Let us now consider man in the free spirit of natural history, as though we were zoologists from another planet completing a catalog of social species on Earth. In this macroscopic view the humanities and social sciences shrink to specialized branches of biology; history, biography, and fiction are the research protocols of human ethology; and anthropology and sociology together constitute the sociobiology of a single primate species.

  *E. O. Wilson, “The Ergonomics of Caste in the Social Insects,” American Naturalist 102 (1968)141–66; George F. Oster and E. O. Wilson, Caste and Ecology in the Social Insects (Princeton: Princeton University Press, 1978).

  *“Competitive and aggressive behavior,” in J. F. Eisenberg and W. Dillon, eds., Man and Beast: Comparative Social Behavior (Washington, D.C.: Smithsonian Institution Press, 1971), pp. 183–217.

  *The Insect Societies (Cambridge, Mass.: Harvard University Press, 1971), p. 460.

  chapter seventeen

  THE SOCIOBIOLOGY CONTROVERSY

  THE SPATE OF REVIEWS THAT FOLLOWED THE PUBLICATION OF Sociobiology in the summer of 1975 whipsawed it with alternating praise and condemnation. Biologists, who as a rule had little stake in the human implications, were almost unanimously favorable. They included Lewis Thomas and C. H. Waddington, elder statesmen of the day. Researchers closest to sociobiology were especially supportive, and they grew more so as time passed. In a 1989 poll the officers and fellows of the international Animal Behavior Society rated Sociobiology the most important book on animal behavior of all time, edging out even Darwin’s 1872 classic, The Expression of the Emotions in Man and Animals.

  Social scientists already engaged in biology-accented research also leaned in favor. They included Napoleon Chagnon, ethnographer of the “Fierce People,” the Yanomamö of Brazil and Venezuela; and the sociologists Pierre van den Berghe and Joseph Shepher, who sought biological explanations of incest avoidance, marriage customs, and other key aspects of human behavior. Paul Samuelson, Nobel laureate economist turned public philosopher, favored the approach in one of his Newsweek columns but said beware—this subject is an intellectual and doctrinal minefield.

  Samuelson was right. A wave of opposition soon rose among social scientists. Marshall Sahlins, a cultural anthropologist, made a strong attempt to exempt human behavior from the tenets of sociobiology in his 1976 book, The Use and Abuse of Biology. In November of that year the members of the American Anthropological Association, gathering in Washington for their annual meeting, considered a motion to censure sociobiology formally and to ban two symposia on the subject scheduled earlier. The arguments of the proposers were mostly moral and political. During the debate on the matter Margaret Mead rose indignantly, great walking stick in hand, to challenge the very idea of adjudicating a theory. She condemned the motion as a “book-burning proposal.” Soon afterward the motion was defeated—but not by an impressive margin.

  Because such events were widely publicized, with some journalists calling the controversy the academic debate of the 1970s, it is easy to exaggerate the depth of the opposition. The serious literature was in fact always strongly disposed toward human sociobiology. In the nearly twenty years since 1975, more than 200 books have been published on human sociobiology and closely related topics. Those more or less in agreement outnumber those against by a ratio of twenty to one. The basic ideas
of sociobiology have expanded (their critics might say metastasized) into fields such as psychiatry, aesthetics, and legal theory. Four new journals were created in the late 1970s to accommodate a rising number of research and opinion articles.

  Regardless of its real strength, much of the controversy might have been avoided, and for that I must bear the responsibility. I had written Sociobiology as two different books in one. The first twenty-six chapters, composing 94 percent of the text, was an encyclopedic review of social microorganisms and animals, with the information organized according to the principles of evolutionary theory. The second, the twenty-nine double-columned pages of Chapter 27 (“Man: From Sociobiology to Sociology”), consisted mostly of facts from the social sciences interpreted by hypotheses on the biological foundations of human behavior. The differences in substance and tone between books one and two give rise to the dual sociobiologies of popular perception. The first is sociobiology as I intended to portray it: a discipline, the systematic study of the biological basis of social behavior and advanced societies. And then there is the evil twin as perceived by Marshall Sahlins and some members of the American Anthropological Association, the scientific-ideological doctrine that human social behavior is determined by genes.

  Genetic determinism, the central objection raised against book two, is the bugbear of the social sciences. So what I said that can indeed be called genetic determinism needs saying again here. My argument ran essentially as follows. Human beings inherit a propensity to acquire behavior and social structures, a propensity that is shared by enough people to be called human nature. The defining traits include division of labor between the sexes, bonding between parents and children, heightened altruism toward closest kin, incest avoidance, other forms of ethical behavior, suspicion of strangers, tribalism, dominance orders within groups, male dominance overall, and territorial aggression over limiting resources. Although people have free will and the choice to turn in many directions, the channels of their psychological development are nevertheless—however much we might wish otherwise—cut more deeply by the genes in certain directions than in others. So while cultures vary greatly, they inevitably converge toward these traits. The Manhattanite and New Guinea highlander have been separated by 50,000 years of history but still understand each other, for the elementary reason that their common humanity is preserved in the genes they share from their common ancestry.