Excerpt from Human Instinct: How Our Primeval Impulses Shape Our Modern Lives, by Lord Robert Winston (Bantam Press, 2003). Reprinted with permission from the author.
From Chapter 7: Co-operation and Altruism
Selfish gene theory
Some species come together simply to mate; they spend most of their time as lone individuals, feeding, sleeping, sheltering and killing as self-sufficient organisms. On the Pleistocene savannah, humans would have been virtually incapable of living alone, not necessarily because of an emotional need to have people around, rather through a sheer inability to survive. Finding food, battling the elements, warding off predators, and bringing up children demanded co-operation. It is likely, therefore, that material needs came first. We must examine whether the mind has adapted to seek co-operative and trusting alliances with people around us. Do we have an instinct for collaboration and sociability? Is not human nature essentially selfish and self-interested?
In 1976, the evolutionary biologist Richard Dawkins published his most famous and brilliant book, The Selfish Gene, and the work has often been misunderstood ever since. His metaphor of the selfish gene was founded on William Hamilton’s work in the early 1960s which emphasized the role of the individual gene as the focus of evolutionary change. As a reminder, the following is a crude version of his thesis. It begins by stating that any gene that promotes its own survival and replication will spread at the expense of other genes. In other words, genes that do well – genes that spread throughout a population – do so because they are, in a sense, self-interested and further their own chances of replication. Genes, of course, do not have any thoughts, feelings or desires, conscious or unconscious, so we should rephrase this: successful genes operate as if they are self-interested entities. This is the first half of the selfish gene theory. The second half goes like this. Organisms are built by genes. Therefore organisms are machines created by genes to enhance the chances of the genes’ replication.
This is an extremely powerful idea, one that even Richard Dawkins himself says continually surprises him. But first let me add another caveat. Genes are not the only factor in the development of an organism. Genes are in many respects quite distant from the coal-face of development. They send protein messengers that instruct other proteins to build structures in the body or the brain, and in different organisms the same gene does not necessarily produce exactly the same structure – consider the small physical differences between ‘identical’ twins. Moreover, the environment can have a considerable effect on how an organism develops.
Broadly speaking, however, the development and final form of an organism are largely dependent on the genes, and they are changed by mutations within the genome. This leads inescapably to Dawkins’ conclusion. To understand the implications of his point of view it is useful to imagine the very beginnings of life on Earth. Before life began there was just the primeval soup, and in the soup there was a mixture of molecules, particularly carbon dioxide and methane, both carbon-based, and water from the gases hydrogen and oxygen. From these simple inorganic molecules and atoms it is relatively easy to make amino acids. Such more complex organic molecules can be synthesized in laboratory conditions that mimic the kind of environment we think existed soon after the beginning of time, an atmosphere with regular electrical discharges, high temperatures and ultraviolet light. It is postulated that these amino acids – the building blocks from which all proteins are composed, essential to life on this planet – started to form chains. Similarly, relatively simple carbon-containing compounds such as sugar and purines were also formed. All these substances are the basic components of nucleotides, and hence DNA. Proteins were made which possibly broke up and recombined randomly. Eventually, by chance, there appeared a few molecules that could make copies of themselves. By combining other amino acids as raw material, they happened to be able to copy their own chemical structures. These molecules, which we can call replicators, spread throughout the primeval soup, reproducing and increasing in number.
But some replicators did not last long. The replication process might have been flawed, thus they made copies that were riddled with errors; the errors built up and eventually, in the final generation of copies of copies, the molecules could no longer replicate themselves. Like a lengthy game of Chinese whispers, the last molecule in the line was effectively gibberish. Others might have been able to make exact copies, every single time, but they would never change and never evolve. They would produce molecule after molecule, copy after copy, without ever developing into something more complex, until they ran out of the more simple proteins that provided the raw material for replication. So exact replication did not guarantee success. Once again, they were an evolutionary dead end.
Long-term success needs a happy medium. It needs a molecule that replicates and makes just enough errors to evolve and adapt to the conditions in which it lives. If one particular variation of this replicator runs out of raw materials, or maybe gets ‘eaten’ – used as raw material to feed another kind of replicator – there will be other variations which may be more successful. Just like the bacteria that mutate and develop immunity to antibiotics, these early replicators will develop immunity against being eaten.
Eventually there was one especially prosperous kind of replicator. By chance, the mechanics of this molecule struck a perfect balance in the copying process – not too exact and not too careless. This replicator had enough adaptability to spread, flourish and eat up all the other kinds of replicator while still retaining its own core ability to reproduce itself. We have a name of the modern descendants of this fantastically successful replicator – DNA. Its offspring are contained within every single cell in every single plant and animal on this planet.
Along the long, twisted double helix of the nucleotides of the DNA replicator lie the parcels of coded information we call genes. Over time, genes mutate and change randomly. Most mutations are pointless, or, worse, are damaging to the survival chances of the genes, but some are helpful, and evolution has shown which genes are good and which are bad.
There is no species of free-swimming DNA in the world’s oceans. The closest that we know about are simple viruses, strands of replicators enclosed by a protective sheath of protein. The instructions for making the protective jacket are encoded in the DNA and these organisms are the precursors of every other kind of animal. The point is that every organism, including human beings, is a kind of protective jacket for DNA. Our cells, which in turn group together to make tissue, bone, skin, blood and nervous systems, are all integral components of our DNA’s extraordinarily complex survival machine. This view is the logical outcome of gene-centred evolution, a bewildering yet unavoidable conclusion. The human body and mind are adaptations ‘designed’ to further the survival of our DNA replicators.
It has long been said, and rarely meant seriously, that a hen is only an egg’s way of making another egg. No-one realized how close this adage was to the truth. Metaphors can go too far; as the geneticist Steve Jones remarked, ‘Evolution is to analogy as statues are to bird-shit’. Possibly Richard Dawkins might be criticized for his evocative labelling of genes as ‘selfish’. However, the central idea – that genes are intent on their own survival – is extremely apt. The individual organism merely becomes a machine for carrying the genes, and the microbe, plant or animal is not the real focus of natural selection.
Why does Dawkins call our genes selfish? They are selfish because their raison d’être is their own survival. The fact that they exist in a current genome means that they have replicated more successfully than their rivals, which are now extinct. Natural selection is all about the spread of successful genes at the expense of not-so-successful genes. These genes do not have to make life pleasant for their or anyone else’s survival machines. As long as the genes can replicate, life for its host organism can be miserable, painful, or just plain dull. Genes do not care. The male redback spider who allows himself to get eaten during copulation is following genetic instructions that have already proven themselves good at making as many copies of themselves as possible; no matter that their host ends his life as lunch for a hungry mother-to-be.
For Dawkins, the gene is not just the primary unit of selection, it can be seen as being a self-interested entity whose overriding ambition is its own survival. Selfishness is therefore a cardinal quality in a gene in which paradoxically its own survival comes before the survival of the host organism. A case in point is the existence of sterile worker castes among social insects.
Many people assumed that because our genes are selfish, so are human beings in their relationships with one another. This is only partly true. Siblings will fight over a last chocolate biscuit. Lovers will fight over commitment or infidelity. Rivals will fight over sexual partners, sometimes resorting to violence, sometimes using psychological ploys or deceit. We all compete over territory, each of us attempting to gain ground at the expense of the other; neighbours squabble over garden boundaries, modern military states clash over disputed land. We are, in these many respects, solely interested in our own well-being, or the well-being of our group, and this self-interest is backed up by a sophisticated armoury of tools and tactics.
But selfishness is not the whole story. Gene-centred evolution – as described by Hamilton, Williams, Trivers and Dawkins – tell us that co-operation and altruism can often be as beneficial to our genes as can competition. After all, our bodies and our brains do not just blindly follow one genetic blueprint. We are ‘designed’ to react in different ways to different situations, and, indeed, in different ways to similar situations. On the savannah our genes played a three-million-year-long game of roulette, random mutation after random mutation, most failing to get the winning number, but a few mutations found themselves useful, even essential, and perpetuated the mortal coil of which they were a part.
In our case, these genes were best served by upgrading their early model host, Australopithecus, into the sociable, co-operative, group-living Home sapiens we are today.
The huge dunes of sand that can be seen along the palm-fringed beaches of Central America contain the nurseries of what must be the worst mother in the world. Each nest, dug some two feet or so into the damp sand, is a dark hiding-place for up to two hundred eggs laid by a female leatherback sea turtle. But having used her massive paddle flippers to scoop out this shallow hole which resembles a shallow grave, she does not stay around. In the dark before dawn, she lumbers back into the warm sea. Around sixty days later, her little hatchlings, miniature, soft-shelled turtles each less than three inches in length, break the shell of their eggs and crawl out of their fragile with hermitage. Digging up through the sand, they take their first tottering steps on a journey of perhaps a hundred metres down the beach to the ocean. These vulnerable little babies must find their own food and fend for themselves. Most will be picked up by birds of prey, lizards and crabs before they even reach the water. Once they reach the sea, a barracuda or a dolphin can swallow a baby turtle in one bite. Their chances of surviving to adulthood are poor. Of those two hundred eggs, an average of two from each nest will survive their youth and grow to sexual maturity.*
Human beings take the opposite tack. We have very few children and make an enormous investment – in terms of time, energy and resources, even placing ourselves at risk of injury or death – in each of them to ensure their survival. Our generosity even extends beyond our children to our close relatives, but the closer the blood relation the more we are willing to do for them. This is a direct result of kin selection and an inescapable consequence of the fact that we share the genes with our children, our parents and our siblings.
We have already seen how social insects provide a vivid example of the degree to which kin selection can affect behaviour. It is so powerful a force, in fact, that worker ants and killer bees will undergo kamikaze missions without a moment’s hesitation. We have also seen the terrible consequences of ‘anti-kin’ selection – male lions killing cubs in their adoptive pride. We, too, are influenced by the mathematics of kin selection, which predicts that a parent who shares one half of his or her genes with a child would be willing to die for two children or two siblings (or four grandchildren, or eight cousins). But behaviour does not adhere to such mechanical calculation. Kin selection gives us a predisposition only, one that makes us more likely to place ourselves in danger to save our children. When a mother dives into a surging river to save her infant, she does not consciously or unconsciously make a calculation; she simply dives in (or not, as the case may be).
Family ties account for a part of our social instinct. The nuclear family structure, such as we see in many birds and other mammals, might have marked the beginnings of our sociability. Modern hunter-gatherers like the Inuit or the Pygmies of the Ituri Forest live in groups tightly bound by family links. Their social organization is fluid. Sometimes they will live in so-called ‘minimal bands’ of around twenty-five or thirty people containing half a dozen nuclear families, but all are firmly connected by family relationships. When food is scarce these bands may split up and each family travel alone. Equally, a number of minimal bands may gather together in one place if there is plentiful food.
So, does Stone Age family life provide the basis for our modern co-operative instincts?
Excerpted from Human Instinct by Lord Robert Winston. Copyright © Robert Winston, 2002. All rights reserved.
Robert Winston is Professor of Science and Society and Emeritus Professor of Fertility Studies at Imperial College, and a member of the British House of Lords. He runs a research programme in the Institute of Reproductive and Developmental Biology on improvements in transgenic technology in animal models, with a long-term aim of improving human transplantation. He has around 300 scientific publications in peer-review journals on reproduction and embryology. He is also Chancellor of Sheffield Hallam University, Chairman of the Royal College of Music, and was voted “Peer of the Year” by his fellow Parliamentarians in June 2008 for his expertise and work on the Human Fertilisation and Embryology Bill. He is committed to scientific education and regularly writes or hosts popular science programmes for the BBC’s main channel, the Discovery and ABC networks. He has published fourteen books for lay readership: What Makes Me Me won the Aventis Prize in 2005, and The Human Mind was short-listed for the same prize in that year. He regularly gives seminars in schools and universities.
Human Instincts – BBC Documentary
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