んどど〃ど川 ac ん / 〃ど instance in refusing tO have as many children as they are able tO. But in this respect man IS a very special case, as we shall see. What has all this to do with altruism and selfishness? I. am trying tO build up the idea that animal behaviour, altruistic or selfish, is under the control of genes in only an indirect, but still very powerful, sense. By dictating the way survival machines and their nervous systems are built, genes exert ultimate power over behaviour. But the moment—to-moment decisions about what tO dO next are taken by the nervous system. Genes are the primary policy—makers; brains are the exeCUt1Ves. But as brains became more highly developed, they t00k over more and more 0f the actual policy decisions, usmg tricks like learning and simulation in dOing SO. The logical conclusion tO this trend, not yet reached ln any species, would be for the genes tO give the survival mach- lne a single overall policy instruction: dO whatever you think best tO keep us alive. Analogies with computers and with human decision—taking are all very well. But now we must come down tO earth and remem— ber that evolution in fact occurs step-by-step, through the differ- ential survival Of genes in the gene POOI. Therefore, in order for a behaviour pattern—altruistlc or selfish¯to evolve' it IS necessary that a gene 、 for' that behaviour should survwe in the gene POOI more successfully than a rival gene or allele 'for' some different behaviour. A gene for altruistic behaviour means any gene which influences the development Of nervous systems ln such a way as t0 make them likely t0 behave altruistically. ls there any experi- mental evidence for the genet1C inheritance Of altruist1C behaviour? No, but that is hardly surprising, since little work has been done on the genetics 0f any behaviour. lnstead' let me tell you about one study 0f a behaviour pattern which does not hap- pen t0 be obviously altruistic, but which is complex enough t0 be interesting. lt serves as a model for hOW altruistic behaviour might be inherited. Honey bees suffer from an infectious disease called foul brood. This attacks the grubs in their cells. Of the domestic breeds used by beekeepers, some are more at risk from foul brood than others' and it turns out that the difference between strams IS, at least in some cases, a behavioural one. 、 here are SO¯called hygiemc strains which quickly stamp out epidemics by locating infected

6 ル 4 を inhibitory nerve centres, it is possible that the female improves the male's sexual performance by eating his head. If so, this is an added benefit. The primary one is that she obtains a good meal. The word 'selfish' may seem an understatement for such ex- treme cases as cannibalism, although these fit well with our defi— nitIOn. Perhaps we can sympathize more directly with the reported cowardly behaviour of emperor penguins in the Antarctic. They have been seen standing on the brink of the water, hesitating before diving in, because of the danger of being eaten by seals. If only one 0f them would dive in, the rest would know whether there was a seal there or not. NaturaIIy nobody wants tO be the gulnea P1g, SO they wart, and sometlmes even try tO push each Other in. More ordinarily, selfish behaviour may simply conSISt in refus- ing tO share some valued resource such as fOOd, territory, or sexual partners. NOW for some examples Of apparently altruistic behaviour. The stinging behaviour 0f worker bees a very effective defence against honey robbers. But the bees who do the stinging are kamikaze fighters. ln the act Of stinging, vital internal organs are usually torn out Of the bOdy, and the bee dies soon afterwards. Her suicide mission may have saved the colony's vital 応 od stocks, but she herself is not around to reap the benefits. By our defini- tion this is an altruistic behavioural act. Remember that we are not talking about conscrous motlves. They may or may not be present, both here and in the selfishness examples, but they are irrelevant tO our definition. Laying down one's life for one's friends is obviously altruistic, but so also is taking a slight risk for them. Many small birds, when they see a flying predator such as a hawk, give a characteris- tic 'alarm call', upon which the whole flock takes appropriate evaslve action. There is indirect evidence that the bird whO gives the alarm call puts itself in special danger, because it attracts the predator's attention particularly t0 itself. This is only a slight additional risk, but it nevertheless seems, at least at first sight, tO qualify as an altruistic act by our definition. commonest and most consPIcu()US acts 0f animal altruism are done by parents, especially mothers, towards their children. They may incubate them, either in nests or in their own bodies,

126 お 4 襯 / ケが 4 / 〃 g family sizes are no longer limited by the finite resources which the individual parents can provide. If a husband and wife have more children than they can feed, the state, which means the rest of the population, simply steps in and keeps the surplus children alive and healthy. There is, in fact, nothing to stop a couple with no material resources at all having and rearing precisely as many children as the woman can physically bear. But the welfare state IS a very unnatural thing. ln nature, parents who have more children than they can support do not have many grandchildren, and their genes are not passed on to future generations. There is no 〃ノ for altruistlc restraint in the birth-rate, because there is no welfare state ln nature. Any gene for over—indulgence promptly punished: the children containing that gene starve. Since we humans dO not want to return to the old selfish ways where we let the children of too-large families starve to death, we have abolished the family as a unit of economic self- sufficiency, and substituted the state. But the privilege of guaran— teed support for children should not be abused. Contraception IS sometrmes attacked as unnatural'. S() it is, very unnatural. The trouble is, SO is the welfare state. I think that most of us believe the welfare state is highly desirable. But you cannot have an unnatural welfare state, unless you alSO have unnatural birth—control, otherwise the end result will be misery even greater than that which obtains ln nature. The welfare state is perhaps the greatest altruistic system the animal kingdom has ever known. But any altruistic system IS inherently unstable because it is open to abuse by selfish individuals, ready to exploit it. lndividual humans who have more children than they are capable Of rearing are probably too ignorant in most cases [ 0 be accused Of consclous malevolent exploitation. Powerful institu— t10ns and leaders whO deliberately encourage them to do so seem tO me less free from susplC1()n. Returning to wild animals, the Lack clutch-size argument can be generalized to all the other examples Wynne-Edwards uses: territorial behaviour, dominance hierarchies, and SO on. Take, for instance, the red grouse that he and his colleagues have worked 0 圧 These birds eat heather, and they parcel out the moors ln territories containing apparently more 応 od than the territory owners actually need. Early in the season they fight over ter-

8 ル 4 尾卯を are competing in what Darwin called the struggle for existence, the individual seems best regarded as a pawn in the game, tO be sacrificed when the greater interest of the species as a whole requires it. TO put it in a slightly more respectable way, a group, such as a specles or a population within a species, whose individual members are prepared to sacrifice themselves for the welfare of the group, may be less likely to go extinct than a rival group whose individual members place their own selfish interests first. Therefore the world becomes populated mainly by groups consisting 0f self-sacrificing individuals. This is the theory of group selection', long assumed tO be true by biologists not familiar with the details of evolutionary theory, brought out into the open in a famous book by V. C. Wynne-Edwards, and popularized by R0bert Ardrey in ど SociaI Co 厩 ra The orthodox alternative IS normally called 'individual selection although I personally prefer to speak of gene selection. The quick answer of the 'individual selectionist' to the argument just put might go something like this. Even ⅲ the group Of altruists, there will almost certainly be a dissenting mlnority WhO refuse tO make any sacrifice. If there is Just one selfish rebel, prepared to exploit the altruism of the rest, then he, by definition, is more likely than they are to survrve and have children. Each of these children will tend to inherit his selfish traits. After several generations Of this natural selection, the 、 altruistic group' will be over-run by selfish individuals, and will be indistinguishable from the selfish group. Even if we grant the lmprobable chance existence initially Of pure altruistic groups without any rebels, it is very difficult to see what is to stop selfish individuals migrating in from neighbouring selfish groups, and, by inter-marrlage, contamlnating the purity Of the altruistlc groups ・ The individual-selectionist would admit that groups do indeed die out, and that whether or not a group goes extinct may be influenced by the behaviour of the individuals in that group. He might even admit that 0 〃な the individuals in a group had the gift of foresight they could see that in the long run their own best interests lay in restraining their selfish greed, to prevent the de- structlon Of the whole group. HOW many times must this have been said in recent years to the working people of Britain? But

4 Ⅲ 4 尾 / Of modern human behaviour, if we really are unique among animals in this respect, it is, at the very least, still interesting tO inquire about the rule tO which we have SO recently become the exception. And if our specles IS not SO exceptional as we might like tO think, it is even more important that we should study the rule. The third thing this book is not is a descriptive account of the detailed behaviour Of man or Of any Other particular animal species. I shall use factual details only as illustrative examples. I shall not be saying: 'lf you 100k at the behaviour 0f baboons you will find it to be selfish; therefore the chances are that human behaviour is selfish also'. The logic of my 'Chicago gangster argument is quite different. lt is this. Humans and baboons have evolved by natural selection. If you look at the way natural selec- tion works, it seems t0 応Ⅱ ow that anything that has evolved by natural selection should be selfish. Therefore we must expect that when we go and 0k at the behaviour of baboons, humans, and all other living creatures, we will find it t0 be selfish. If we find that our expectation IS wrong, if we observe that human behaviour is truly altruistic, then we will be faced with something puzzling, something that needs explaining. Before going any further, we need a definition. An entity, such as a baboon, IS said tO be altruistic if it behaves ln such a way as tO lncrease another such entity's welfare at the expense Of its own. SeIfish behaviour has exactly the opposite effect. 、 WeIfare' defined as 'chances Of survival', even if the effect on actual life and death prospects is so small as t0 ど襯 negligible. One 0f the surpr1S1ng consequences Of the modern verSIOn Of the Darwiman theory is that apparently trivial tiny influences on survival proba- bility can have a maJOr lmpact on evolution. This is because Of the enormous time available for such influences tO make them— selves felt. lt is important tO realize that the above definitions Of altruism and selfishness are みどん 40 〃′ 4 / , not sub)ective. I れ not con— cerned here with the psychology 0f motives. I am not going t0 argue about whether people wh0 behave altruistically are 'really' dOing it for secret or subconsclous selfish motives. Maybe they are and maybe they aren't, and maybe we can never know, but in any case that is not what this bOOk is about. 、 ly definition is

ル〃なな 2 concerned only with whether the く〃とは Of an act is tO lower or raise the survival prospects Of the presumed altruist and the sur— vival prospects 0f the presumed beneficiary. lt is a very complicated business tO demonstrate the effects Of behaviour on long—term survival prospects. ln practice, when we apply the definition t0 real behaviour, we must qualify it with the word 'apparently'. An apparently altruistic act is one which looks, superficially, as if it must tend t0 make the altruist more likely (however slightly) t0 die, and the recipient more likely t0 survive. lt Often turns out on closer lnspection that acts Of apparent altruism are really selfishness in disguise. Once again, I dO not mean that the underlying motives are secretly selfish, but that the real effects Of the act on survival prospects are the reverse Of what we originally thought. I am going to give some examples 0f apparently selfish and apparently altruistic behaviour. lt is difficult t0 suppress subjec- tive habits Of thought when we are dealing with our own species, SO I shall choose examples from Other animals instead. First some miscellaneous examples of selfish behaviour by individual animals. BIackheaded gulls nest in large colonies, the nests being only a few feet apart. When the chicks first hatch out they are small and defenceless and easy to swallow. lt is quite common for a gull t0 wart until a neighbour's back is turned, perhaps while it IS away fishing, and then pounce on one 0f the neighbour's chicks and swallow it whole. lt thereby obtains a good nutritlous meal, with- out having to go t0 the trouble 0f catching a fish, and without having tO leave lts own nest unprotected. More well known is the macabre cannibalism of female praymg mantises. Mantises are large carmvorous lnsects. They normally eat smaller insects such as flies, but they will attack almost any- thing that moves. When they mate, the male cautiously creeps up on the female, mounts her, and copulates. If the female gets the chance, she will eat him, beginning by biting his head off, either as the male is approaching, or lmmediately after he mounts, or after they separate. lt might seem most sensible for her tO walt until copulation is over before she starts tO eat him. But the IOSS of the head does not seem to throw the rest of the male's body off its sexual stride. lndeed, since the insect head is the seat Of some 5

どを 7 feed them at enormous cost tO themselves, and take great risks in protecting them from predators. TO take just one particular example, many ground-nesting birds perform a so-called 'distrac- tion display' when a predator such as a fox approaches. The parent bird limps away from the nest, holding out one wmg as though it were broken. The predator, sensing easy prey, is lured away from the nest containing the chicks. Finally the parent bird gives up its pretence and leaps intO the air Just in time tO escape the fox's jaws. lt has probably saved the life 0f its nestlings, but at some risk tO itself. I am not trying to make a point by telling stories. Chosen examples are never serl()us evidence for any worthwhile gener— alization. These stones are simply intended as illustrations Of what I mean by altruistrc and selfish behaviour at the level 0f individuals. This book will show how both individual selfishness and individual altruism are explained by the fundamental law which I am calling g ど訪雇 But first I must deal with a particular erroneous explanation for because it iS widely known, and even widely taught in sch001s. This explanation is based on the misconception which I have already mentioned, that living creatures evolve tO dO things 、応 r the good of the species' or 'for the good 0f the group'. lt is easy t0 see how this idea got its start in biology. Much 0f an animal's life is devoted tO reproduction, and most Of the acts Of altruistic self— sacrifice WhiCh are observed in nature are performed by parents towards their young. 、 Perpetuation Of the specles IS a common euphemism for reproduction, and it is undeniably a CO 〃イ〃ど〃 Of reproduction. lt requires only a slight over-stretching Of logic tO deduce that the 、 function' Of reproduction is tO perpetuate the species. From this it is but a further short false step tO conclude that animals will in general behave in such a way as tO favour the perpetuation Of the species. Altruism towards fellow members Of the specles seems tO 応Ⅱ OW. This line of thought can be put int0 vaguely Darwiman terms. Evolution works by natural selection, and natural selection means the differential survival Of the 'fittest'. But are we talking about the fittest individuals, the fittest races, the fittest species, or what? For some purposes this does not greatly matter, but when we are talking about altruism it is obviously crucial. If it is specres which

much that is Of interest 応Ⅱ OWS. For instance, altruistic behaviour could evolve, not because 0f benefit to the genes 0f the individual himself, but solely because of benefit to his parents' genes. paren- tal manipulation, tO use Alexander's term, becomes an alternatlve evolutionary cause Of altruistic behaviour, independent of straightforward kin selection. lt is therefore important that we examine Alexander's reasomng, and convmce ourselves that we understand why he is wrong. This should really be done mathe- matically, but we are avoiding explicit use of mathematics in this bOOk, and it is possible to give an intuitive idea of what is wrong with Alexander's thesis. His fundamental genetic point is contained in the following abridged quotation. 'Suppose that a Juvenile . cause(s) an uneven distribution Of parental benefits in its own favor, thereby reducing the mother's own overall reproduction. A gene which in this fashion improves an individual's fitness when it IS a Juvenile cannot 信ⅱ tO lower its fitness more when it is an adult, for such mutant genes will be present in an lncreased proportion Of the mutant individual's offspring. ' The fact that Alexander is con- sidering a newly mutated gene IS not fundamental tO the argument. lt is better tO think Of a rare gene inherited from one Of the parents. 、 Fitness' has the special technical meaning Of reproductive success. What Alexander is basically saymg is this. A gene which made a child grab more than his fair share when he was a child, at the expense Of his parent's tOtal reproductive output, might indeed increase his chances Of survivmg. But he would pay the penalty when he came to be a parent himself, because his own children would tend tO inherit the same selfish gene, and this would reduce his overall reproductive success. He would be hoist with his own petard. Therefore the gene cannot succeed, and parents must always win the conflict. Our suspicions should be immediately aroused by this argument, because lt rests on the assumptlon Of a genetic asym— metry which is not really there. Alexander is using the words parent' and 'offspring as though there was a fundamental genetic difference between them. As we have seen, although there are pra な 4 / differences between parent and child, for instance parents are Older than children, and children come out Of parents bodies, there is 1 ℃ ally no fundamental g ど〃ど行 c asymmetry. The 146

7 ・、んど g ど〃ど川〃 C ん / 〃ど for their lives. They are judged according t0 the success of their programs in copmg with all the hazards which life throws at their survival machines, and the judge is the ruthless judge of the court Of survival. Ⅵ発 shall come later tO ways in which gene survival can be fostered by what appears t0 be altruistic behaviour. But the obvious first priorities Of a survival machine, and of the brain that takes the decjsions for it, are individual survival and reproduction. All the genes in the 'colony' would agree about these priorities. Animals therefore go t0 elaborate lengths t0 find and catch fOOd; tO avoid being caught and eaten themselves; tO avoid disease and accident; tO protect themselves from unfavour— able climatlc conditions; tO find members Of the opposite sex and persuade them tO mate; and tO confer on their children advan- tages similar t0 those they enJOY themselves. I shall not give examples—if you want one Just 100k carefully at the next wild animal that you see. But I dO want tO mentlon one particular kind of behaviour because we shall need to refer to it again when we come tO speak Of altruism and selfishness. This is the behaviour that can be broadly labelled 川襯〃〃れ、 10 〃 . A survival machine may be said tO have communicated with another one when it influences its behaviour or the state Of its nervous system. This is not a definition I would like tO have tO defend for very long, but it is good enough for present purposes. By influence I mean direct causal influence. Examples Of com— mumcatlon are numerous: song in birds, frogs, and criAts; tail— waggmg and hackle-raismg in dogs; grinmng in chimpanzees; human gestures and language. A great number Of survival- machine actions promote their genes' welfare indirectly by influencing the behaviour Of Other survival machines. Animals go tO great lengths tO make this communlcation effective. The songs Of birds enchant and mystify successlve generations Of men. I have already referred tO the even more elaborate and mysterlous song 0f the humpback whale, with its prodigious range, its frequencles spanning the whole 0f human hearing from subsonic rumblings to ultrasomc squeaks. M01e-crickets amplify their song tO stentorian loudness by singing down ln a burrow which they carefully dig in the shape of a double exponential horn, or mega- phone. Bees dance in the dark tO give Other bees accurate infor— mation about the direction and distance Of fOOd, a feat Of

50 7 ど g ど〃ど川 ac ん feel like a unit, not a colony. This is to be expected. SeIection has favoured genes which cooperate with others. ln the fierce com— petition for scarce resources, in the relentless struggle tO eat Other survival machines, and tO avoid being eaten, there must have been a prermum on central coordination rather than anarchy within the communal body. Nowadays the intricate mutual co- evolution Of genes has proceeded tO such an extent that the com- munal nature Of an individual survival machine IS virtually unrecognizable. lndeed many biologists dO not recognize it, and will disagree with me. FortunateIy for what journalists would call the 、 credibility' of the rest of this book, the disagreement is largely academic. Just as it is not convenient tO talk about quanta and fundamental par- ticles when we discuss the workings Of a car, SO it iS ()ften tedious and unnecessary tO keep dragglng genes in when we discuss the behaviour Of survival machines. ln practice lt IS usually conven— ient, as an approximation, tO regard the individual bOdy as an agent 'trying tO increase the numbers Of all its genes in future generatlons. I shall use the language Of convenlence. Unless Other— Wlse stated, 'altruistic behaviour' and 'selfish behaviour' will mean behaviour directed by one animal bOdy toward another. This chapter is about みどん 4 物・ 0 〃たーー the trick of rapid movement which has been largely exploited by the animal branch of survival machines. Animals became actlve go—getting gene vehicles: gene machines. The characterlStic Of behaviour, as biologists use the term, is that it is fast. Plants move, but very slowly. 、 Vhen seen ln highly speeded-up film, climbing plants look like active animals. But most plant movement IS really irreversible growth. Animals, on the other hand, have evolved ways of moving hundreds of thousands Of times faster. Moreover, the movements they make are reversible, and repeatable an indefinite number Of times. The gadget which animals evolved to achieve rapid movement was the muscle. Muscles are engines which, like the steam englne and the internal combustion engine, use energy stored in chemical fuel tO generate mechanical movement. The difference is that the immediate mechanical force Of a muscle is generated in the form Of tension, rather than gas pressure as in the case of the steam and internal combustion engmes. But muscles are like engmes in that they Often exert their force on cords, and levers