The Selfish Gene

by Richard Dawkins

The more you think about it, the more you realize that life is riddled with Iterated Prisoner’s Dilemma games,

nice strategy is defined as one that is never the first to defect. Tit for Tat is an example. It is capable of defecting, but it does so only in retaliation.

when psychologists set up games of Iterated Prisoner’s Dilemma between real humans, nearly all players succumb to envy and therefore do relatively poorly in terms of money. It seems that many people, perhaps without even thinking about it, would rather do down the other player than cooperate

an ‘I win, you lose’ tussle? The chances are, only the lawyers. The hapless couple have been dragged into a zero sum game. For the lawyers, however, the case of Smith v. Smith is a nice fat nonzero sum game, with the Smiths providing the pay-offs and the two professionals milking their clients’ joint account in elaborately coded cooperation.

I was having tea with A company when we heard a lot of shouting and went to investigate. We found our men and the Germans standing on their respective parapets. Suddenly a salvo arrived but did no damage. Naturally both sides got down and our men started swearing at the Germans, when all at once a brave German got on to his parapet and shouted out ‘We are very sorry about that; we hope no one was hurt. It is not our fault, it is that damned Prussian artillery.’

The live-and-let-live system could have been worked out by verbal negotiation, by conscious strategists bargaining round a table. In fact it was not. It grew up as a series of local conventions, through people responding to one another’s behaviour

Natural selection favours some genes rather than others not because of the nature of the genes themselves, but because of their consequences—their phenotypic effects.

V. Imp

‘The rabbit runs faster than the fox, because the rabbit is running for his life while the fox is only running for his dinner.’

In the world of the extended phenotype, ask not how an animal’s behaviour benefits its genes; ask instead whose genes it is benefiting.

A body, then, is not a replicator; it is a vehicle.

‘A gene is defined as any portion of chromosomal material that potentially lasts for enough generations to serve as a unit of natural selection.’

genes ‘determine’ behaviour only in a statistical sense

Hurting religious sensibilities is a perilous business these days, so I had better oblige.

genes do not control their creations in the strong sense criticized as ‘determinism’. We effortlessly (well, fairly effortlessly) defy them every time we use contraception.

A gene could be defined as any hereditary information for which there is a favorable or unfavorable selection bias equal to several or many times its rate of endogenous change.

It is one of the most important consequences of the universally admitted fact that the ‘Lamarckian’ theory of inheritance is false.

am reminded of P. B. Medawar’s remark about the attractions of ‘philosophy-fiction’ to ‘a large population of people, often with well-developed literary and scholarly tastes, who have been educated far beyond their capacity to undertake analytical thought’.

The mind, with its serial stream of consciousness, is a virtual machine, a ‘user-friendly’ way of experiencing the brain, just as the ‘Macintosh User Interface’ is a user-friendly way of experiencing the physical computer inside its grey box.

An ESS is a strategy that does well against copies of itself.

was this macabre habit, in the related Ichneumon wasps, that provoked Darwin to write: ‘I cannot persuade myself that a beneficent and omnipotent God would have designedly created the Ich-neumonidae with the express intention of their feeding within the living bodies of Caterpillars … ’ He might as well have used the example of a French chef boiling lobsters alive to preserve the flavour.

So the whole ‘strategy’, ‘If dominant behave as a “slave”, if subordinate behave as a “master” ’, is rewarded and therefore stable.

Altruism is expected towards individuals whose relatedness is higher than the baseline, whatever the baseline happens to be.

‘Twelve Misunderstandings of Kin Selection’

He also tells us the right and wrong way to calculate costs and benefits to genetic relatives.

Why has natural selection favoured these genes, even though some of them end up in the bodies of sterile soldiers and are therefore not passed on? Because, thanks to the soldiers, copies of those very same genes have been saved in the bodies of the reproductive non-soldiers.

Moreover, being a true clone, the aphids are no more ‘social’ than the cells of your body. There is a single animal feeding on the plant. It just happens to have its body divided up into physically separate aphids, some of which play a specialized defensive role just like white blood corpuscles in the human body.

snail shell is an exquisite logarithmic spiral, but where does the snail keep its log tables; how indeed does it read them, since the lens in its eye lacks ‘linguistic support’ for calculating m, the coefficient of refraction? How do green plants ‘figure out’ the formula of chlorophyll?

If C is my identical twin …

Such Olympic ideals are too much of a luxury for the Darwinian games: effort in one direction is always paid for as lost effort in another direction. It is as if the more effort you put into any one race, the less likely you are to win future races because of exhaustion.

The key idea here is that a small initial difference between the sexes can be self-enhancing: selection can start with an initial, slight difference and make it grow larger and larger, until the As become what we now call males, the Bs what we now call females. The initial difference can be small enough to arise at random. After all, the starting conditions of the two sexes are unlikely to be exactly identical.

‘Why don’t male mammals lactate?’

Briefly, then, we can draw two conclusions: (a) that the battle of sexes has much in common with predation; and (b) that the behaviour of lovers is oscillating like the moon, and unpredictable as the weather.

He believes that hereditary disease-resistance among males is the most important criterion by which females choose them. Disease is such a powerful scourge that females will benefit greatly from any ability they may have to diagnose it in potential mates. A female who behaves like a good diagnostic doctor and chooses only the healthiest male for mate will tend to gain healthy genes for her children.

But erection failure is a known early warning of diabetes and certain neurological diseases.

So selection pressure from females forced males to lose the os penis, because then only genuinely healthy or strong males could present a really stiff erection and the females could make an unobstructed diagnosis.

Advertising is costly. In other words, if we could somehow ignore the effects of quality and attractiveness, a male would be better off not advertising (thereby saving energy or being less conspicuous to predators). Not only is advertising costly; it is because of its costliness that a given advertising system is chosen. An advertising system is chosen precisely because it actually has the effect of reducing the success of the advertiser—all other things being held equal. 4. Advertising is more costly to worse males. The same level of advertising increases the risk for a puny male more than for a strong male. Low-quality males incur a more serious risk from costly advertising than high-quality males.

The essential feature of haplodiploid animals, from the point of view of social evolution, is that an individual can be genetically closer to her sibling than to her offspring. This predisposes her to stay behind in the parental nest and rear siblings rather than leaving the nest to bear and rear her own offspring.

Either we must be ‘genetic determinists’ or we believe in ‘free will’; we cannot have it both ways. But—and here I presume to speak for Professor Wilson as well as for myself—it is only in the eyes of Rose and his colleagues that we are ‘genetic determinists’. What they don’t understand (apparently, though it is hard to credit) is that it is perfectly possible to hold that genes exert a statistical influence on human behaviour while at the same time believing that this influence can be modified, overridden, or reversed by other influences. Genes must exert a stastical influence on any behaviour pattern that evolves by natural selection.