Spike Jones <firstname.lastname@example.org> writes:
> Anders Sandberg wrote:
> > ...Since sexual responsiveness in depression is usually strongly
> > decreased, I don't think it helps reproduction at all. I'm sceptical
> > about arguments for an evolutionary "meaning" of depression; it
> > doesn't have to be a feature, just a weakness that ordinarily doesn't
> > matter much...
> You may be right Anders, but I can see a way around this particular
> argument. If male sex drive decreases during a long-winter induced
> depression, then presumably it would result in fewer October babies.
> Perhaps this would compensate for the otherwise higher number of
> October babies caused by increased face time by mates in January
> and February. Presumably an April or May baby in the far north
> would have a higher probability of survival?
> The argument then would be ancient populations were much more
> limited by food shortages than by lack of sexual activity.
This certainly makes sense, at least in far northern areas. It is
interesting to note that seasonal affective disorder is most common in
Scandinavia and among people descended from scandinavians. Also,
testosterone levels are apparently lower in early spring which could
also be an evolved control.
> I have only myself to experiment upon, but I find it interesting that
> my own appetite decreases noticeably in the darkest months. I
> could see where this would create a survival advantage in those
> populations that had this feature, if they lived in the far northern
> latitudes. Someone here has said evolution does not work at
> this level but still I cannot understand why not. spike
It seems like a gene for SAD would likely spread just due to less
chance of babies being born in the wrong season, so i think your idea
makes much sense. There are likely other similar ways of controlling
when reproduction occurs, but since we evolutionarily speaking left
the tropics yesterday (where the seasons and food availability are
different and presumably human reproduction can be done the year
arond) there is no rigid reproduction control like in most other
animals, rather just influences of likeliehood of reproducing.
-- ----------------------------------------------------------------------- Anders Sandberg Towards Ascension! email@example.com http://www.nada.kth.se/~asa/ GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y
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