Trivers' Reciprocal Altruism

From: Jon Wright (
Date: Wed Oct 29 1997 - 17:20:21 GMT

Trivers's model of altruism works as an exchange of acts between
any two organisms. They need not be of the same species just so long as
one reciprocates to the other will the altruistic relationship flourish.

It differs from the previous idea that altruism is kin selection,
based in a certain amount of relatedness between benefactor and
recipient. In the case of relatives it may well be the case that one
gives far more than it recieves (typical of parents giving
unconditionally to offspring) but maybe the relatedness is overriding
the reciprocal nature of altruism.

Altruism functions most reliably when three conditions are

1) there are many altruistic acts performed over a lifetime, or
rather that the lifetime of a relationship is long enough to reciprocate

2) the altruist acts within a small set of other individuals so
that altruistic 'debts' are more easily repaid

3) partners are mutually dependent, ie. that two (or more)
people can do better than alone, for example the big grouper fish cannot
survive for long without the cleaner fish or hunter-gatherer packs.

I think that in a moment of crisis, the way people behave is
more likely to be dependent on their general attitude toward others and
their past experiences and influences (like Superman, perhaps). Some
people are more likely to be leaders than others and those will be more
likely to place themselves at greater risk. In the PiperA disaster, the
two workers who tried to get back to the control room from the
accomodation quarters would most likely have been more predisposed to
such actions and taking charge than others.

Human altruism is very complicated and indeed the whole argument
could be reduced to the point where one only does things because one
wants to and so that in itself is a satisfying experience. It makes it
impossible to be disinterested in the outcome of any act.

The notion that subjective feelings of guilt, gratitude,
friendship, sympathy and so on are the result of evolution is not
unconvincing (to me), as seemed to be the general opinion in the
seminar. It is useful to be able to explain these feelings in terms of
the regulation of altruistic situations and exchanges. Gratitude is felt
towards someone who does you a favour and as such the favour is repaid
(assuming no cheats). The repayment of the favour causes a positive
feeling between those people (trustworthiness) and future cooperation is
more likely, ensuring survival and the passing on of genes. A gene
favouring 'gratitude' will survive.

Cheats always muscle in on this, and it is because of these
cheats that altruism needs to be reciprocated, else it would stop after
one act.

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