Thursday, March 12, 2009

The origins of virtue

I read Matt Ridley's 'The origins of virtue' just now. It was full of engaging anecdotes and irrelevant details, which I don't find that useful for understanding, so I wrote down the interesting points. On the off chance anyone else would like a summary, I publish it here. I recommend reading it properly. Things written in [here] are my comments.



The aim of this book: How did all this cooperation and niceness, especially amongst humans, come about evolutionarily?

Chapter 1

There are benefits to cooperation: can do many things at once, [can avoid costs of conflict, can enjoy other prisoners' dilemmas, can be safer in groups]

Cooperation occurs on many levels: allegiances, social groups, organisms, cells, organelles, chromosomes, genomes, genes.

Selfish genes explain everything.

Which means it's possible for humans to be unselfish.

There are ubiquitous conflicts of interest to be controlled in coalitions at every level.


Relatedness explains most groupishness ( = like selfishness, but pro-group). e.g. ants, naked mole rats.

Humans distribute reproduction, so aren't closely related to their societies. They try to suppress nepotism even. So why all the cooperation?

Division of labour has huge benefits (trade isn't zero sum)

[cells are cool because they have the same genes, so don't mutiny, but different characters so benefit from division of labour]

Division of labor is greater in larger groups, and with better transport.

There is a trade-off between division of labour and benefits of competition.

By specialising at individual level a group can generalise at group level: efficiently exploit many niches.

Division of labour between males and females is huge and old.


Prisoners' dilemmas are ubiquitous.

Evolutionarily stable strategies = nash equilibria found by evolution.

Tit-for-tat and related strategies are good in iterated prisoners' dilemmas.

This is because they are nice, retaliatory, forgiving, and clear.

If a combination of strategies play against one other repeatedly, increasing in number according to payoffs, the always-defectors thrive as they beat the always-cooperators, then the tit-for-taters take over as the defectors kill each other.

Reciprocity is ubiquitous in our society.

Hypothesis: it's an evolutionarily stable strategy. It allowed us to benefit from cooperation without being related. This has been a major win for our species.

Reciprocity isn't as prevalent between related individuals (in ours and other species).

Tit-for-tat can lead to endless revenge :(


Reciprocity requires remembering many other individuals and their previous behavior. This requires a large brain.

Reciprocity requires meeting the same people continually. Which is why people are nastier in big anonymous places.

Other strategies beat tit-for-tat once tit-for-tat has removed nastier strategies. Best of these is pavlov, or win-stay/lose-shift, especially with learned probabilities.

In asynchronous games 'firm-but-fair' is better – similar to pavlov, but cooperates [once presumably] after being defected against as a cooperator in the last round.

In larger populations reciprocity should be less beneficial – most interactions are with those you won't see again.

Boyd's suggestion: this is the reason for morality behaviour, or punishing those who don't punish defection.

Another solution: social ostracism: make choosing who to play with an option.

A strategy available to humans is prediction of cooperativeness in advance. [Why can we do this? Why don't we evolve to not demonstrate our lack of cooperativeness? Because others evolve to show their cooperativeness if they have it? There are behaviours that only make sense if you intend do be cooperative.]


We share food socially a lot, with strangers and friends. Not so much other possessions. Sex is private and coveted.

Meat is especially important in shared meals.

Hypothesis: meat hunting is where division of labour was first manifested.

Monkey males share meat with females to get sex, consequently hunting meat more than would be worth it for such small successes otherwise.

Hypothesis: humans do this too (some evidence that promiscuous natives hunt more), and the habit evolved into a sexual division of labour amongst married couples (long term relationships are usual in our species, but not in chimps). Males then benefit from division of labour, and also feeding their children.

Hypothesis: sexual division of labour fundamental to our early success as a species – neither hunting or gathering would have done alone, but together with cooking it worked.

Hypotheses: food sharing amongst non-relatives could have descended from when males of a tribe were mostly related, or from the more recent division of labour in couples.

Chimps share and show reciprocity behaviour, but do not offer food voluntarily [doesn't that suggest that in humans its not a result of marriage related sexual division?]

Why do hunter-gatherers share meat more, and share more on trips?

Hypotheses: 1. meat is cooperatively caught, so have to share to continue cooperation. 2. High variance in meat catching – sharing gives stable supply.

What stops free-riding then?


Mammoth hunting introduced humans to significant public goods. You can't not share a mammoth, especially if others have spear throwers. [mammoth hunting should have started then when it became easier to kill a mammoth than to successfully threaten to kill a tribesman who killed a mammoth]

Tolerated theft: the idea that people must share things where they can't use all of them, and to prevent others from taking parts is an effort. That is, TT is what happens once you've caught a public good (e.g. mammoth). Evidence that this isn't what happens in reality; division seems to be controlled. Probably reciprocity of some sort (argument over whether this is in the form of material goods or prestige and sex). Evidence against this too; idle men are allowed to share (if the trade is in sex, they aren't the ones the trading is aimed at, and miss out on the sex trade).

Alternative hypothesis: is treated as a public good, but so big that it's possible to sneak the best bits to girls and get sex.

Trade across time (e.g. in large game) reduces exposure to fluctuations in meat.

Hypothesis: hunter-gatherers are relatively idle because they have to share what they get, so stop getting things after their needs are fulfilled.

Hypotheses: when people hoard money they are punished by their neighbours because they are defecting in the reciprocal sharing that usually takes place, yet they have no incentive to share if they have an improbably large windfall – the returned favours won't be as good. Alternatively can be seen as tolerated theft: punishment for not sharing is an attempt to steal from huge good.

When instincts for reciprocity are in place, gifts can be given 'as weapons'. That is, to force future generosity from the recipient.

Gift giving is less reciprocal (still prevalent, just not carefully equal) amongst human families than amongst human allies.

Gifts can then also signal status; ostentatious generosity demands reciprocity – those who can't lose face. The relative benefit of buying status this way depends on the goods – perishables may as well be grandly wasted. In this case reciprocity is zero sum: no benefits from division of labour, status cycle is zero sum.


Humans are better at solving Wason test when it is in terms of noticing cheating than in terms of other social contexts, or abstract terms.

Hypothesis: humans have an 'exchange organ' in their brains, which deals with calculating related to social contracts. This is unique amongst animals. Evidence: brain damage victims and patients who fail all other tests of intelligence except these, anthropomorphic attitudes to nature heavily involve exchange, anthropomorphizing of objects heavily involves exchange related social emotions (anger, praise).

Moral sentiments appear irrational, but overcome short term personal interests for long term genetic gains.

Commitment problem: when at least one side in a game has no credible threat if the other defects, how can cooperation occur? The other can't prove they will commit. e.g. kidnap victim can't prove she won't go to police, so kidnapper must kill her even if both would be better off if he let her go in return for her silence.

Various games have bad equilibria for rational players in one off situations, but emotions can change things. e.g. prisoners' dilemma is solved if players have guilt and shame. Where player would be irrational to punish other for defection (punishment costly to implement, loss already occurred), anger produces credible threat (will punish in spite of self).

Many emotions serve to alter the rewards of commitment problems, by bringing forward costs and benefits.

For this to work, emotions have to be hard to fake. Shouldn't defectors who are good at faking emotions invade a population of people who can't? No, because in the long run the people who can't find each other and cooperate together. [that's what would happen anyway – you would cooperate the first time, then don't go back if the other defects. Commitment should be a problem largely in one off games – are more emotions shown in those things? In one off games can't have the long run to find people and make good liars pay].

Emotions make interests common, which stops prisoners' dilemmas. Interests of genes are not common, so emotions must be shared with other emotional ones.

Ultimatum game variations suggest that people are motivated more by reciprocity than by absolute fairness.

People lacking social emotions due to brain damage are paralyzed by indecision as they try to rationally weigh information.

We like and praise altruism much more than we practice it. Others' altruism and our looking altruistic are useful, whereas our own selfishness is. [why aren't people who behave like this invaded by slightly more altruistic ones who don't cooperate with them? Why is the equilibrium at being exactly as selfish as we are? Signaling means that everyone looks more altruistic than they are, so everyone is less altruistic than they would be if others were maximally altruistic?]

Hypothesis: economics and evolutionary biology are held in distrust because talking about them doesn't signal belief in altruism etc. Claiming that people or genes are selfish suggests that you are selfish.


Cooperation began (or is used primarily in monkey society) in competition and aggression.

The same 'tricks' will be discovered by evolution as by thought [if their different aims don't matter], so if we share a behaviour with animals it's not obvious that it's evolved in our case, though often it is.

Our ancestors were: social, hierarchical (especially amongst males), more egalitarian and with less rigid hierarchies than monkeys.

Differences between primates:

Monkey hierarchies rely on physical strength more than chimp ones, which rely on social manipulation.

Baboons use cooperation to steal females from higher ranking males, chimps use it to change the social hierarchy.

Chimp coalitions are reciprocal, unlike monkeys.

Power and sexual success are had by coalitions of weaker individuals in chimps and humans.

Bottlenose dolphins (the only species other than us with brain:body ratio bigger than chimps): males have coalitions of 2-3 which they use to kidnap females. All mate with her. These coalitions join to form super-coalitions to steal females from other coalitions. This is reciprocal (on winning, one coalition will leave the female with the other coalition in the super-coalition, in return for the favor next time)

Second order alliances seem unique to dolphins and humans.

Chimp males stay in a troop while females leave, with monkeys it is the other way around. Could be related to aggressive xenophobia of chimp males. Seems so in human societies: matrilineal societies are less fighty.

Chimp groups, rather than individuals, possess territory (rare, but not unique: e.g. wolves).

Hypothesis: this is an extension of the coalition building that occurs for gaining power in a group. Alpha males prevent conflict within the group, making it stable, which is good for all as they are safer from other groups if they stick together.

Humans pursue status through fighting between groups, whereas chimps only do it within groups [how do you know?]


Group selection can almost never happen.

Large groups cooperating are often being directly selfish (safer in shoal than alone).

50:50 sex ratio is because individual selection stronger than group selection. A group would do better by having far more females, yet a gene to produce males would make you replicate much faster, bringing ratio back.

Humans appear to be exception: culturally, not genetically, different groups compete.

Conformism would allow group characteristics to persist long enough that there would be group selection before groups dissolved or were invaded by others' ideas.

Why would conformism evolve?

Hypothesis: we have many niches which require different behaviors. If you move it's beneficial to copy your behavior from your neighbors.

Imitation should be more beneficial if there are more people doing it; better to copy something tried by many than the behavior of one other. How did it get started then?

Hypothesis: seeing what is popular amongst many gives you information.

Hypothesis: keeps groups together. If receptive to indoctrination about altruism we will find ourselves in more successful groups [I don't follow this].

Humans don't actually live in groups; they just perceive everything in terms of them.

A persons' fate isn't tied to that of their group. They don't put the group's wellbeing first. They are groupish out of selfishness – it's not group selection.

Ritual is universal, but details of it are particular.

Hypothesis: Ritual is a means to conformity keeps groups together in conflict, and they survive [How would this begin? Why ritual? Why do they have to be different? Why is conformity necessary to keep groups together? Seems just that we are used to conformity being linked to staying together we assume one leads to the other].

Music and religious belief seem to have similarly group grouping properties.

Cooperation within groups seems linked to xenophobia outside them [cooperation for safety in conflict is of course. What about cooperation for trade? Has that given us non-xenophobia induced cooperative feelings? Earlier chapters seemed to imply so].


Weak evidence of trade 200,000 years ago – not clear when it started.

Trade between groups is unique to humans.

Trade is the glue of alliances between groups; it appears that some trade is just an excuse for this.

Trading rules predate governments. Governments nationalize preexisting trading systems. e.g. 11th C Europe merchant courts [is this a general trend? why is everything in anecdotes? aargh].

Speculation isn't beneficial because there is no division of labour [?].


Natives are not ecologically nice. They do not conserve game. They sent many species extinct.

We tie environmentalism up with other morality [is it pro-social morality, as the book has been about, or purity?].

As with other morality, we are more programmed to preach than to practice.

It doesn't look like people have an instinctive environmental ethic [it's a big prisoners' dilemma – can't we make use of something else in our repertoire?].


Property rights emerge unaided where it is possible to defend them [if you see a tragedy of the commons coming, best to draw up property rights – no reason you will be the free rider].

Nationalization often turns property-divided 'commons' into a free for all, as the govt can't defend it and nobody has reason to protect what they are stealing from.

Ordered and successful systems can emerge without design. e.g. Bali subak traditions could have resulted from all copying any neighbour who did better than them.

Lab experiment suggests that communication encourages a lot of cooperation in tragedy of commons games (better than ability to fine defectors)

If humans can arrange property rights unaided, why all the extinctions last chapter?

Hypothesis: property rights can't be enforced on moving things. Animals that could have property rights asserted on them did have in some cases. e.g. Beavers.

Hoarding taboo (as a result of reciprocity instinct) is to blame for environmentalist dislike of privatisation as a solution.

Hoarding isn't allowed in primitive tribes, but as soon as more reliable lifestyle allows powerful individuals to do better by hoarding than relying on social insurance, they do. Yet we retain an aversion to it.


Humans are born wanting to cooperate, discriminate trustworthiness, commit to trustworthiness, gain a reputation, exchange goods and info, and divide labour.

There was morality before the church, trade before the state, exchange before money, social contracts before Hobbes, welfare before rights, culture before Babylon, society before Greece, self interest before Adam Smith and greed before capitalism.

Also tendency to xenophobic groups is well inbuilt.

How can we make use of our instincts in designing institutions?

Trust is fundamental to cooperative parts of human nature being used.

This has been part of an endless argument about the perfectability of man, famously between Hobbes and Rousseau. Also about how malleable human nature is. [The book goes into detail about the argument over the centuries, but it's an irrelevant story to me].

To say that humans are selfish, especially that their virtue is selfish, is unpopular because saying so encourages it supposedly.

Big state doesn't make bargains with the individual, engendering responsibility, reciprocity, duty, pride – it uses authority. How do people respond to authority?

Welfare state replaces existing community institutions based on reciprocity and encouraging useful feelings, having built up trust over the years. Centralised replacements like the National Health Service. Mandatory donation → reluctance, resentment. Client feelings changed from gratitude to apathy, anger, drive to exploit the system.

:. Government makes people more selfish, not less.

We must encourage material and social exchange between people, for that is what breeds trust, and trust is what breeds virtue.

Our institutions are largely upshots of human nature, not serious attempts to make the best of it.

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