Re: Underestimating 'r'
- From: Tim Tyler <tim@xxxxxxxxxxx>
- Date: Wed, 5 Oct 2005 21:22:59 -0400 (EDT)
Jim McGinn <jimmcginn@xxxxxxxxx> wrote or quoted:
> Tim's interested in understanding the
> selective origins of altruism and related social behaviors. There are
> many people that believe (wrongly IMO) that Darwin's understanding of
> natural selection is inconsistent with the observations that many
> species--including our own--have high degrees of altruism and social
> behaviors. Some people, mistakenly IMO, believe that Hamilton's rule
> solves this mystery. Tim is pointing out that when you actually
> examine the evidence closely and honestly it is apparent Hamilton's
> rule predicts something very different from what is actually observed.
I did include this in the post:
``If so, what's the practical effect of this? As far as I can
tell, the effect would be pretty limited. It ought to make
individuals behave somewhat altruistically to other members
of their species. However there are a raft of other theories
that predict this sort of thing (e.g. reciprocal altruism) -
so the effect may be hard to tease out. It wouldn't make
*much* difference to how relatives are treated - since
their relative relatednesses would remain pretty much
the same. [...]''
I'm not really arguing with Hamilton's rule - just wondering
to what extent factors such as inbred populations and distant
shared ancestry influence "r" upwards.
[Re: The key is to have clearly stated definitions, understood
by all involved]
> I definitely agree with this last statement. If Hamilton had done this
> he'd have seen the error of his ways. Hamilton never defined
> relatedness. Instead he just through out the assumption that it was
> defined by genes IBD = R.
In "TGEOSB I", Hamilton wrote: "the coefficient r measures the expected
fraction of genes i.b.d in a relative".
Hamilton also clamed that this was equal to Sewal Wright's coefficient
of relationship, r in a non-inbred population.
Hamilton later had a rethink of all this, resulting in - among other
things - the idea that r could be negative.
> People that believe that Hamilton's rule has causal validity have been
> duped by he ambiguity of Hamilton's use of the word relatedness. They
> assume falsely that Hamilton's notion of relatedness indicates the
> degree the behavior in one lifeform can be predicted in the related
> lifeform.
That would be a *very* bad assumption.
That's practically never what the term "relatedness" means in biology -
and I'd be rather suprised to learn that there are very many students
of biology who think the term commonly has that meaning.
--
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- Underestimating 'r'
- From: Tim Tyler
- Re: Underestimating 'r'
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- Underestimating 'r'
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