Lately, I've become a believer in the limits of reductionist explanations especially in areas like complex systems and biology. So, without wasting any more time, I'll get to my question..

Whenever we think of something like cooperation, the most common explanation that comes up is that of genetic fitness. It is said that evolution would have selected for psychological mechanisms of cooperation because it is beneficial in a society in which reciprocity is possible. You scratch my back, and I scratch yours. Add to the mix the ability to name names, and reputation becomes a kind of proxy signal for fitness.

Now, the major problem I have with this is does it all have to boil down to fitness? Can't it be a phenomenon that is culture-specific? Different cultures go to different lengths to help a stranger. Yet, we all share the same evolutionary history. This seems like a strong indicator that cooperation can't be reduced to one's genetic or reputational fitness alone. Should the study of cooperation be handed off to the anthropologists?

  • $\begingroup$ All animals are not humans ! So handing over to anthropologists - Bad option ! $\endgroup$
    – biogirl
    Feb 19, 2014 at 12:19
  • 1
    $\begingroup$ Sorry, I should have been more specific that I meant human altruism. $\endgroup$
    – Joebevo
    Feb 19, 2014 at 12:20
  • $\begingroup$ Ok! then I completely agree with you. Human altruism is far more complex than other animal altruism. (I also suggest that you edit your question to be more specific) $\endgroup$
    – biogirl
    Feb 19, 2014 at 12:23
  • $\begingroup$ You have to define altrusim here. In evolutionary biology altruism often refers to an evolutionary adaptation where some individuals in a species are unable to reproduce, supporting a breeding caste. e.g. ants and bees. Humans do not do this. I think you are actually thinking of what biologists call Cooperation. $\endgroup$
    – shigeta
    Feb 19, 2014 at 20:04
  • $\begingroup$ Inclusive fitness proponents will tell you that this explanation is completely wrong, by they way (without being an expert, I tend to agree). $\endgroup$ Feb 20, 2014 at 13:36

2 Answers 2


Interesting question!

I think that in terms of 'tribal' fitness, altruism would be strongly selected for, as communities would tend to be quite small (relative to, say, a town today). In modern civilization cultures have developed differing levels of altruism, but I imagine this is a result of upbringing rather than inherent differences in tendency toward altruistic actions.

So in my opinion you cannot rule out altruism being selected for because it is clearly an advantage (in terms of survival / fitness) in smaller communities - we just don't live in that kind of society any more; people don't have to be altruistic to get by, and this kind of mind-set can 'evolve' culturally, outside genetics. But on the whole I would still argue that most people are inclined toward altruism - ether because they feel naturally inclined to help others, or feel that by helping others some benefit (such a reputation) would be bestowed upon them (the former may be the same as the latter, but at an unconscious level).


There are many various model used in order to explain evolution of cooperation. Here is a small list:

  • kin selection

  • group selection (levels of selection)

  • lineage selection

  • Reciprocity

    • direct
    • indirect
    • network
  • Memetics

People from many different background study social evolution including

  • mathematicians
  • biologists
  • philosophers
  • computer scientists
  • paleontologists

Social evolution is studied through fundamental science (using mathematical modelling and computer simulation) or by looking for common trait among species that are very social. For example, it seems that having a high extrinsic mortality rate "helps" a species evolving altruistic behaviors. Or sex determination mechanism such as haplo-diploidy seem to be important too. There are many experimental studies on human behavior too.

The field you referenced to ("Can't it be a phenomenon that is culture-specific") is called memetics. A meme (named by analogy with the word gene) is a cultural unit which reproduces according to their "memetic fitness" and mutates. There are lots of computer simulations on the subject and there are several empirical observations such as the evolution of a joke.

I think that none of the field we manage to think it would help explaining the evolution of cooperation is neglected. There are several articles who investigate the co-evolution between genes and memes. I don't know any of them who focused on the question of altruism. I have to confess that I have never read any article who considered the combined effects of several models from several fields in the study of altruism. But I don't think we have a sufficient level of understanding of each field in order to combine these models. For example, it's been argued that kin selection and group selection is actually the same process.


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