I read that in "The Red Queen" by Matt Ridley. Racism and xenophobes are samples of these behavior.

Is this true? And if it's true, how does that work?

For example. Evolutionary psychology predict that humans tend to be altruistic to relatives. A gene that motivate me to sacrifice my life for 2 of my children, 2 brothers or 8 cousins will propagate.

In the 1930s J.B.S. Haldane had full grasp of the basic quantities and considerations that play a role in kin selection. He famously said that, "I would lay down my life for two brothers or eight cousins".[8] Kin altruism is the term for altruistic behaviour whose evolution is supposed to have been driven by kin selection.

By the way Haldane is half joking. For those who want to know the Math, genetic similarity between 2 relatives can be measured 1/2^(distance among relatives) multiplied by common ancestors. Your brothers have 1/2 genetic similarity with you and your cousins have 1/8 genetic similarity with you.

Curiously the way it works is not by humans actively want to max out their relative genetic success. The gene it self selfishly try to max out his reproductive success by main controlling the host (humans) to "lay down my life for two brothers or eight cousins". Okay I may be wrong here so please correct me on this one.

It's the main idea of Selfish Gene by Richard Dawkins. The gene itself, not you, is selfish. The reason why you are selfish is because genes that promote selfishness selfishly reproduce. So individuals are not purely selfish and are often altruistic to friends (reciprocal altruism) and to familes (kin altruism).

But what about non relatives that are similar? I do not see similar mechanism show up? Can anyone explain how.

Note: This is indeed a notable claim. I read that in the Red Queen. I just couldn't find a reference on that yet. We can sort of guess it's notable though because xenophobia is real and evolutionary psychology is sort of "comprehensive" in figuring out humans' nature.

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    The text is slightly confusing (or -ed): what you’re describing is not the main idea of The Selfish Gene; rather, it’s the main idea of kin selection. TSG formulates the premises necessary to make kin selection work. Which, by the way, were already implicitly apparent to Haldane. But TSG itself is not a book about kin selection, it’s much more general. Commented Oct 30, 2011 at 11:31
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    Different note (hence different comment): “non relatives” in the above is a red herring. We are all related through our genes. So the same mechanism that applies to kin selection applies (at least mathematically) to the more distantly related organisms. And yes, the claim is certainly notable in that it’s the working hypothesis that most evolutionary biologists subscribe to. Commented Oct 30, 2011 at 11:34
  • Matt Ridley himself covered the ground better in his later book The Origins of Virtue. And it is obvious that the narrow Haldane-spoofed view isn't enough to explain altruistic behaviour.
    – matt_black
    Commented Oct 30, 2011 at 20:44

2 Answers 2


Cooperation is far more common than any theory based on "cooperate with people like you" would predict

The trouble with this question is that is is a very big one which others have written whole books about so any summary will be incomplete and perhaps overly simple.

The most important conclusion is that cooperation between people goes far beyond what Haldane's numbers would predict and that reciprocal altruism base on consanguinity is not a good explanation for actual cooperation.

There are three key books that describe these ideas well: The Evolution of Cooperation by Robert Axelrod; The selfish Gene by Richard Dawkins; the Origins of Virtue by Matt Ridley (all links to latest editions on Amazon).

Haldane's numbers describe the mathematics of rational cooperation from the point of view of genetic success. It makes sense to display some degree of self sacrifice of an individual if their genes are preserved in the other relatives saved by the sacrifice. The theme of Dawkins' book is working out the implications of that view for biological behaviour. But rather too many people read the title and not the book and somehow never get to the penultimate chapter which (in my edition at least) is called Nice Guys Finish First. The chapter gives a summary of the work of Axelrod. Matt Ridley's book explores this theme in more detail.

What Axelrod did provides a powerful illustration that cooperation can be very effective for the individual and the group in ways that are far more significant for real behaviour than preferential behaviour to relatives. His basic idea was to create a computer model of individuals who would compete against each other in interactions with a Prisoner's Dilemma style payoff. The prisoner's dilemma is just about the simplest description of a two player game where the results are not trivial and where something like a real-world tradeoff between short and long term payoffs matters (the rational strategy in a single game is selfish, but if you know you will play repeatedly, you can do much better if you are not selfish). The beauty of the very simple game is how it captures the essence of some real interactions between people where the result is not zero-sum (i.e. the size of the pie can get bigger or smaller depending on how you play so there is more at stake than just what share you get).

Axelrod ran a simulation of many competing strategies for playing the game and ran competitions to see if experts in computer science, game theory and biology could develop effective strategies. The successful algorithms were allowed to grow in number; the less successful killed off in a long game with many rounds (in modern language he created a simulated ecosystem where individual bots with a particular strategy could recognise other bots they had interacted with before). The critical finding is what sort of strategy is successful in the long term: a selfish one, a greedy one, an altruistic one, a complex one and so on. Naively "nice" algorithms get exploited by nasty ones but if the population is all nasty, nasty ones don't do well either. Amazingly one of the simplest algorithms possible often comes out on top: tit-for-tat. It has the characteristics (as described by Dawkins) of

Tit for tat... is 'nice' meaning never the first to defect, and 'forgiving' meaning it has a short memory for past misdeeds. Tit for tat is also 'not envious' ...[which is] to be quite happy if the other player wins just as much money as you do.

There is a lot more detail which I highly recommend people to read, but the key point relevant to this question is just this: Axelrod's simulation demonstrates that cooperative behaviour can emerge from interacting individuals with no concept at all of kin selection (at least if you are playing a non zero-sum game).

Many creatures have the capability to cooperate for mutual benefit with their own species and with entirely different species (e.g. those small birds or fish that clean carnivores' teeth and never get eaten). Many species exhibit self-sacrificial behaviour with non-related individuals. Dawkins ends the description of this by describing mutualistic behaviour in Vampire bats where individuals who have had a good feed will regurgitate blood for unrelated bats who have not had a good feed. he ends the chapter with these words:

Vampires could form the vanguard of a comfortable new myth,a myth of sharing, mutualistic cooperation. They could herald the benignant idea that, even with selfish genes at the helm, nice guys can finish first.

The key point of all this is you don't need to be related to engage in and benefit from cooperative behaviour and that many of the actual examples of cooperation are not derived from the rules about how related we are, but from this, more powerful, drive for mutual benefit.

And, perhaps even more importantly for the original question, cooperation doesn't depend on whether the cooperating parties are similar. Otherwise different species couldn't develop symbiotic relationships. The critical issue driving cooperation is repeated interaction between people who recognise each other. This suggests that the correct prediction is that people will be more altruistic to other people they repeatedly interact with and those others may be completely unrelated.

  • +1 Well, so how do we resolve racism then? Also why would a terrorist commit an altruistic act of suicide bombing against swinger? I called that altruistic because the individual is death (lost), but his fellow anti sex outside marriage bigots will have less competition and hence survive better in the gene pool because of his act.
    – user4951
    Commented Feb 27, 2012 at 5:22
  • There are several problems with the work of Axelrod. Ken Binmore, a well-known expert on evolutionary and classical game theory, gave a very critical assesment in a review of one of Axelrods books. Commented May 29, 2012 at 20:06
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    "cooperation doesn't depend on whether the cooperating parties are similar", it is however a lot more likely between related individuals. Especially when you account for the difficulties in detecting relatedness.
    – John
    Commented Jan 22, 2019 at 21:47
  1. Appearance is governed by relatively few genes compared to the total number (better studied in dogs than humans), so appearance alone isn't a good indication that you share genes with others.

  2. Humans have a strong tendency to be altruistic towards an in-group and hostile towards an out-group (Wikipedia has a good summary). Part of the evolutionary advantage of this may come from factors you describe (i.e. those genes that promote that behavior tend to be found in reproductively successful tribes; and people within a tribe look a bit more similar than those outside, so it's something to run the in/out distinction off of).

  • The rest is math I guess. Can we conclude that this may explain suicide bombing? After all the cost of just one life (even though it's your own) may be well compensated by increased reproductive success of your kind.
    – user4951
    Commented Oct 30, 2011 at 7:55
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    @Jim “Can we conclude that this may explain suicide bombing?” – Most certainly not! That is too far a leap of faith (pardon the pun). Commented Oct 30, 2011 at 11:36
  • @Jim Thio - Depends what you mean by "explain". Non-altruistic beings would not conduct suicide bombings except perhaps to save their own children. So in that this is one of many necessary conditions, it could be part of the explanation. Not the most relevant part, I don't think, since most people are altruistic (and have in/out group rivalries) and yet are not suicide bombers.
    – Rex Kerr
    Commented Oct 30, 2011 at 17:19
  • @Jim - suicide bombing is no different than any other tactics where you use the increased risk to yourself as leverage (e.g. force multiplier). The only difference is that specifically with a bomb, the value of the multiplier is higher.
    – user5341
    Commented Nov 1, 2011 at 0:25
  • @JimThio the only difference is that historically suicide bombings in the last century were heavily used in uncivilized context (e.g. by attacking civilians), or in attacks - in violation of Geneva convention - without a uniform. That cultural context doesn't make the tactics any special as far as game theory goes.
    – user5341
    Commented Nov 1, 2011 at 1:44

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