Received: by alpheratz.cpm.aca.mmu.ac.uk id RAA04523 (8.6.9/5.3[ref firstname.lastname@example.org] for cpm.aca.mmu.ac.uk from email@example.com); Mon, 28 Jan 2002 17:34:50 GMT Message-Id: <firstname.lastname@example.org> X-Sender: email@example.com X-Mailer: QUALCOMM Windows Eudora Version 5.1 Date: Mon, 28 Jan 2002 12:32:17 -0500 To: firstname.lastname@example.org From: Keith Henson <email@example.com> Subject: Origin of Depression In-Reply-To: <3C55714D.14344.821EB1@localhost> References: <firstname.lastname@example.org> <3C533158.8424.4352F6@localhost> Content-Type: text/plain; charset="us-ascii"; format=flowed Sender: email@example.com Precedence: bulk Reply-To: firstname.lastname@example.org
At 03:42 PM 28/01/02 +0100, <email@example.com>
>On 27 Jan 2002, at 12:45, Keith Henson wrote:
> > It is actually remarkable simple. As Hamilton said one time, he should be
> > willing to die if it would save more than 2 brothers or more than 8
> > cousins. If you understand that a brother carries half your genes and a
> > cousin one eighth of your genes it is obvious math to see that genes
> > favoring this level of sacrifice would be favored over the long term.
>Hm, but what about those family fathers who murder their whole
>family and commit suicide afterwards?
You don't need to include the family to ask evolutionary questions about
suicide and the depression that drives most of it. Evolutionary psychology
principles tell you that something which looks horribly counter survival
for the genes is generally a side effect of some character that in a lesser
amount or in the ancestral environment promoted reproductive success.
It is a good assumption (because most genes work that way) that a number of
genes contribute to characteristics we observe. I think skin color has
been estimated to be the outcome of 15-20 genes, plus the environmental
effect of sun exposure darkening the skin.
I don't know what the purpose might be of the genes which (in excessive
numbers) lead to depression. They could have been a way to conserve energy
when the prospects of hunting were unfavorable. They might be a way to
keep mania in check. Mania could be an outcome of having too many genes
for excessive optimism and/or working hard--and that we can understand that
since our ancestors who worked hard to feed their families left more
offspring. (Though not so many as the ones who figure out how to get
*others* to work hard for them. <grin>)
So it is a good bet to assume an assortment of "mood" genes out there. You
draw some from each parent. Most of the time you get a decent mix and are
fine, but if you get too many either way chances are high you will be
"trimmed" from the end of the bell curve, like those who are on the extreme
ends of the smart/stupid or the short/tall curves. "Trimming" here means
death before reproduction or failure to reproduce. In equilibrium
individuals far out on the curves fail to reproduce in about equal
numbers. If this was not the case, the center point of the curve would
drift up or down over generations until this condition was being met.
Questions like this are a lot more interesting to consider in the light of
evolutionary psychology and other such mental tools.
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