The Selfish Gene

by Richard Dawkins

They express a preference for ‘natural’ methods of population limitation, and a natural method is exactly what they are going to get. It is called starvation.

are not passed on to future generations. There is no need for altruistic restraint in the birth rate, because there is no welfare state in nature. Any gene for over-indulgence is promptly punished:

Our conclusion from this chapter is that individual parents practise family planning, but in the sense that they optimize their birth rates rather than restrict them for public good.

Genes for investing in more helpless individuals in preference to oneself can prevail in the gene pool, even though the beneficiaries may share only a proportion of one’s genes. This is why animals show parental altruism, and indeed why they show any kind of kin-selected altruism.

An elder brother may have exactly the same grounds for altruism as a parent: in both cases, as we have seen, the relatedness is , and in both cases the younger individual can make

As soon as a runt becomes so small and weak that his expectation of life is reduced to the point where benefit to him due to parental investment is less than half the benefit that the same investment could potentially confer on the other babies, the runt should die gracefully and willingly.

A. Zahavi has suggested a particularly diabolical form of child blackmail: the child screams in such a way as to attract predators deliberately to the nest. The child is ‘saying’ ‘Fox, fox, come and get me.’ The only way the parent can stop it screaming is to feed it. So the child gains more than its fair share of food, but at a cost of some risk to itself.

This is analogous to holding a pistol to your brother’s head rather than threatening to blow yourself up.

It seems to me just conceivable that the true explanation has nothing to do with cuckoos at all. The blood may chill at the thought, but could this be what baby swallows do to each other? Since the firstborn is going to compete with his yet unhatched brothers and sisters for parental investment, it could be to his advantage to begin his

egg; a share by tipping out another. Translating into gene language, a gene for fratricide could conceivably spread through the gene pool, because it has 100 per cent chance of being in the body of the fratricidal individual, and only a 50 per cent chance of being in the body of his victim.

If there is a human moral to be drawn, it is that we must teach our children altruism, for we cannot expect it to be part of their biological nature.

We had usually thought of sexual behaviour, copulation, and the courtship that precedes it as essentially a cooperative venture undertaken for mutual benefit, or even for the good of the species!

These criteria for judging the sex of an individual are all very well for mammals but, for animals and plants generally, they are no more reliable than is the tendency to wear trousers as a criterion for judging human sex.

This therefore places a limit on the number of children a female can have, but the number of children a male can have is virtually unlimited. Female exploitation begins here.*

Males, then, seem to be pretty worthless fellows, and on simple ‘good of the species’ grounds, we might expect that males would become less numerous than females. Since one male can theoretically produce enough sperms to service a harem of 100 females we might suppose that females should outnumber males in animal populations by 100 to 1. Other ways of putting this are that the male is more ‘expendable’, and the female more ‘valuable’ to the species.

There is no reason why a man should not inherit a tendency to develop a long penis from his mother.

Since she starts by investing more than the male, in the form of her large, food-rich egg, a mother is already at the moment of conception ‘committed’ to each child more deeply than the father is. She stands to lose more if the child dies than the father does.

The female sex is exploited, and the fundamental evolutionary basis for the exploitation is the fact that eggs are larger than sperms.

From the point of view of a female trying to pick good genes with which to ally her own, what is she looking for? One thing she wants is evidence of ability to survive.

To begin with, then, we have to imagine females choosing males on the basis of perfectly genuine labels or indicators which tend to be evidence of good underlying genes.

The result of this is that one of the most desirable qualities a male can have in the eyes of a female is, quite simply, sexual attractiveness itself.

Originally, then, females may be thought of as selecting males on the basis of obviously useful qualities like big muscles, but once such qualities became widely accepted as attractive among the females of the species, natural selection would continue to favour them simply because they were attractive.

under the name of sexual selection.

succeed in convincing the females. In other words Zahavi believes that a he-man must not only seem to be a good quality male: he must really be a good quality male; otherwise, he will not be accepted as such by sceptical females.

This is because females with a taste for handicapped males will automatically tend to be selecting males with good genes in other respects, since those males have survived to adulthood in spite of the handicap.

birds. Now in nature this shaping of the calls must have been produced by natural selection, and we know what that means. It means that large numbers of individuals have died because their alarm calls were not quite perfect.

It was Hamilton who brilliantly realized that, at least in the ants, bees, and wasps, the workers may actually be more closely related to the brood than the queen herself is!

If a male is known to possess a gene A, what are the chances that his mother shares it? The answer must be 100 per cent, since the male had no father and obtained all his genes from his mother. But now suppose a queen is known to have the gene B. The chance that her son shares the gene is only 50 per cent, since he contains only half her genes. This sounds like a contradiction, but it is not. A male gets all his genes from his mother, but a mother only gives half her genes to her son.

Therefore the relatedness between hymenopteran full sisters is not as it would be for normal sexual animals, but

It follows that a hymenopteran female is more closely related to her full sisters than she is to her offspring of either sex.*

Genes trying to manipulate the world through queen bodies are outmanoeuvred by genes manipulating the world through worker bodies.

True warfare in which large rival armies fight to the death is known only in man and in social insects.

Trivers goes so far as to suggest that many of our psychological characteristics—envy, guilt, gratitude, sympathy, etc.—have been shaped by natural selection for improved ability to cheat, to detect cheats, and to avoid being thought to be a cheat.

Language seems to ‘evolve’ by non-genetic means, and at a rate which is orders of magnitude faster than genetic evolution.

really shows what cultural evolution can do. Language is only one example out of many. Fashions in dress and diet, ceremonies and customs, art and architecture, engineering and technology, all evolve in historical time in a way that looks like highly speeded up genetic evolution, but has really nothing to do with genetic evolution.

The new soup is the soup of human culture. We need a name for the new replicator, a noun that conveys the idea of a unit of cultural transmission, or a unit of imitation. ‘Mimeme’ comes from a suitable Greek root, but I want a monosyllable that sounds a bit like ‘gene’. I hope my classicist friends will forgive me if I abbreviate mimeme to meme.

memes should be regarded as living structures, not just metaphorically but technically.

God exists, if only in the form of a meme with high survival value, or infective power, in the environment provided by human culture.

Does anything analogous occur in meme pools? Has the god meme, say, become associated with any other particular memes, and does this association assist the survival of each of the participating memes? Perhaps we could regard an organized church, with its architecture, rituals, laws, music, art, and written tradition, as a co-adapted stable set of mutually-assisting memes.

The idea of hell fire is, quite simply, self perpetuating, because of its own deep psychological impact. It has become linked with the god meme because the two reinforce each other, and assist each other’s survival in the meme pool.

Memes for blind faith have their own ruthless ways of propagating themselves. This is true of patriotic and political as well as religious blind faith.

When we die there are two things we can leave behind us: genes and memes.

Socrates may or may not have a gene or two alive in the world today, as G. C. Williams has remarked, but who cares? The meme-complexes of Socrates, Leonardo, Copernicus, and Marconi are still going strong.

We are built as gene machines and cultured as meme machines, but we have the power to turn against our creators. We, alone on earth, can rebel against the tyranny of the selfish replicators.*

many wild animals and plants are engaged in ceaseless games of Prisoner’s Dilemma, played out in evolutionary time.

The temptation to defect must be better than the reward for mutual cooperation, which must be better than the punishment for mutual defection, which must be better than the sucker’s pay-off.

The conclusion is that, regardless of which card you play, my best move is Always Defect.

That is why the game is called a dilemma, why it seems so maddeningly paradoxical, and why it has even been proposed that there ought to be a law against it.

you will see that neither has any choice but to betray the other, thereby condemning both to heavy sentences. Is there any way out of the dilemma? Both players know that, whatever their opponent does, they themselves cannot do better than defect; yet both also know that, if only both had cooperated, each one would have done better.

The iterated game