Hamilton's rule

I want to thank the person who explained the meanings
of the symbols used in Hamilton's rule a couple of
days ago, but I can't find the post and don't remember who
it was. Anyway, thank you. Now everything people are
saying makes more sense: "b" is benefit, "c" is cost, etc.

In this post I intend to describe my understanding of
what Hamilton's rule says, gleaned from this newsgroup
plus some logic and common sense. I'm not claiming that
it is or isn't what Hamilton described; it's my version
of something that makes sense to me that might be
the same or similar. Comments welcome.

The rule talks about the circumstances under
which genes for altruistic behaviour tend to
be evolutionarily successful.

The rule applies in contexts in which reciprocal altruism can
be ignored. By reciprocal altruism I mean acts of
generosity or cooperation which are done with an
expectation of reward. Contexts in which this can
be ignored include: contexts in which the recipient of
the generosity doesn't know who did it or is not
even aware that an act of generosity occurred; contexts
in which the receiver has no opportunity to provide
a reward; contexts in which no reward-giving behaviour
has evolved in that species; and contexts in which the
entire expected lifetime set of cascading rewards from an
act have already been counted as part of the "cost"
and "benefit" of the act.

Definitions:

relatedness (The famous "r"!): A factor varying from
0 (two unrelated individuals) to 1 (fully related;
the same individual). This factor is calculated using
the part of the family tree for which the organism
can reasonably be expected to have reasonably complete
and accurate information. "r" is the ratio of the
number of genes that would be expected to be identical
between the two individuals as a result of being
passed down through that part of the family tree,
to the total number of genes in an individual.
For example,
for mammals, "r" for direct offspring is 0.5, the expected
value of "r" for full siblings is 0.5 and
for half-siblings 0.25, for cousins is 1/8, etc.

benefit, "b": the value in terms of evolutionary
fitness of an organism of the benefit to the recipient
from an act of altruism.

cost, "c": the cost, similarly in terms of fitness, to the
one doing the act of altruism.

Here's the rule:

A gene is evolutionarily stable if it causes the
organism to carry out the act of altruism whenever
rb > c, and not to carry out the act
whenever rb < c.
--
Cathy Woodgold
http://www.ncf.ca/~an588/par_home.html
We are all Iraqis now.

.

Relevant Pages

  • Re: Hamiltons rule
    ... > The rule applies in contexts in which reciprocal altruism can ... > expectation of reward. ... Contexts in which this can ... > even aware that an act of generosity occurred; ...
    (sci.bio.evolution)
  • Re: Hamiltons rule
    ... This is an interesting inversion of the way kin selection is usually treated ... think) than Trivers' model of reciprocal altruism, ... Contexts in which this can ... > even aware that an act of generosity occurred; ...
    (sci.bio.evolution)
  • Re: Property sheet, ad hoc, property page, flexible data
    ... Just like ACT allowed you ... to have "property sheets" we would like to do something similar. ... > The other requirement is that the data in the data base be sharable and ... This is not a requirement or expectation. ...
    (comp.databases.theory)
  • Re: Future generations
    ... conserve energy and other natural resources simply because someone ... act, call on their energy providers, etc... ... be saying we should fix social security or reduce the deficit simply ... In academic circles 'intergenerational altruism' is often used to mean ...
    (alt.usage.english)
  • Re: Applying TDF (was understanding y)
    ... >>> chooses to carry out an act of altruism whenever ... >>> an act of altruism. ... >>> Many generations later, what genes are likely ... Of course, if a and b are rare, any selection pressure favouring ...
    (sci.bio.evolution)
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