lamoran{at}bioinfo.med.utoronto.ca (Larry Moran) wrote in
news:bvjhhu$1b75$1{at}darwin.ediacara.org: 

> On Sat, 31 Jan 2004 00:52:40 +0000 (UTC), 
> William Morse  wrote:
>> lamoran{at}bioinfo.med.utoronto.ca (Larry Moran) wrote in
>> news:bv23as$25ct$1{at}darwin.ediacara.org: 
 
> In order for beauty to be selected you have to have certain alleles
> segregating within the population. There have to be alleles that
> control beauty and alleles that control our reponse to this beauty.
> Furthermore, the hypothesis has to do far more than just explain
> why we think something is beautiful. It has to explain why this 
> might have an effect on the ability to reproduce. So far, I haven't
> seen any data to suggest that there's a serious difference in the
> ability of beautiful men and women to reproduce. I also haven't
> seen any serious attempt by the hypothesis to describe this. (In
> fainess, it's probably assumed to be obvious that only people
> with beautiful faces will get a mate. The fact that's there's no
> data to support this assumption seems to be ignored ... as is the 
> common sense observation that most men and women have children
> eve if they aren't beautiful.)

As has been pointed out, there do not have to be alleles that control 
beauty if what we perceive as beautiful is based on features (symmetry, 
averageness) that are surrogates for good health. There only have to be 
alleles that control our response to the beauty . And, as I think you are 
well aware, the hypothesis does _not_ have to explain a difference in 
"ability" to reproduce. It only has to explain a  long term higher 
reproductive success  in those who choose to reproduce with attractive 
people than in those who choose to reproduce with unattractive people. In 
a reasonably large population with significant mixing (where drift is, of 
course, irrelevant) a relatively small difference in reproductive success 
will result in an appreciation for beauty being selected.


 
> I prefer explanations based almost exclusively on cultural (societal)
> patterns of behavior and what we learn when we are growing up. To
> me, this explains the wide variety of different perceptions of
> beauty in different cultures and the change in this perception
> within a single culture over time. In other words, this behavior
> doesn't have a direct genetic component and doesn't have anything much
> to do with evolution, in my opinion.

I am glad that you prefer such explanations. But there is not in fact a 
"wide" variety of perceptions of beauty. Faces considered attractive in 
one culture are also considered attractive in other cultures, and very 
young infants will preferentially look at faces that are considered 
attractive by adults.  So culture is not  an "exclusive" explanation, 
although it certainly plays a role. Now there have been explanations put 
forward for cross-cultural facial attractiveness based on built-in bias 
in our perceptual system, and this may be the correct explanation. 


 
> I also like to compare human behavior with that of our closest 
> evolutionary relatives in order to get a reality check on the latest 
> evolutionary speculations about human behavior. In this case, I don't 
> think that there's any evidence for chimps being particularly picky 
> about their choice of mating partners. Thus, the speculators have to 
> add one more thing to their hypothesis. Not only do they speculate 
> about genes for beauty and genes for the perception of beauty but now 
> they have to speculate that these genes mostly arose within the human
> lineage in the past 5 million years. That's asking an awful lot for
> a speculation that doesn't even have any evidence to support it.
> (I'm talking about evidence for evolution.)

I also like such reality checks. Unfortunately there is a significant 
difference in mating behavior between humans and chimpanzees - we are 
monogamous, they are not. And there is no way to know whether our LCA was 
picky about  choice of mating partner. If it was, then _you_ would have 
to explain why chimps are not picky, and would similarly have to 
speculate that those genes mostly arose within the chimp lineage in the 
past 5 million years. Living primates exhibit almost the entire range of 
mating behaviors, based on ecological niche rather than cladistics, so 
comparisons to chimps are not necessarily germane. One of the interesting 
things I found out while looking into this subject is that in gibbons, 
many species of which  are monogamous, the females sing!
 
 
> If there is no strong genetic component to beauty and no strong
> *genetic* connection between being beautiful and preferring beautiful
> partners, then we're not talking about evolution.

Why does "genetic" have to be involved.Your own definition of evolution 
is "heritable", not "genetic". So a memetic explanation
should be 
allowable - but that is a subject best left to another thread. I think we 
both have serious, albeit different, reservations about memetics.
 
 
> A lot of people seems to making the assumption that just because we
> have an idealized image of (culturally derived) beauty it means that 
> we will only marry the ideal woman or man. This isn't the kind of
> world that I see around me. How about you?

You may be right about a lot of people. _My_ argument is assortative 
mating. That _is_ the kind of world that I see around me - beautiful 
women marry rich and successful men (or sometimes poor but handsome men), 
while poor, dumb, and ugly men marry similar women. I happen to have been 
extraordinarily lucky in that my lovely and talented wife was willing to 
marry me :-) 



> This is just one part of the speculation. The idea being challenged
> above is that selection for beauty can be explained by a correlation
> between beauty and health. I'm going further. I'm challenging the
> entire idea that beauty is being selected in human populations for
> whatever reason.

Is your argument that:

1) there is no such thing as a cross-cultural standard for beauty, so it 
can not be selected? 

2) beauty is adaptive, but selection for it is overwhelmed by drift?

3) beauty exists, but it is not genetic? 

4) Some other that I am missing?


Yours,

Bill Morse
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