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Why are women more brightly colored (whereas in other animals males usually are)?

by Khantazm
Tags: animals, brightly, colored, males, women
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Khantazm
#1
Oct23-12, 03:45 PM
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So, possibly I'm looking for the explanation according to Richard Dawkins, but I'd welcome all points of view. Why do women dress more brightly (when men still do the courting), while in other animals the sex that is courting is more bright (and loud)?
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Hermes0128
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Oct24-12, 11:32 PM
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In my opinion, our society is more complex than animal societies and the relationships are more complex, so the "courting rituals" are more complex. People aren't just looking for someone to mate with, they are looking for someone they are personally and emotionally compatible with, to the ends of being able to sustain a relationship for many years. I think some women dress brightly because they want to attract the type of person that is drawn to the personality they present - I think they're informing males of the criteria they're looking for in order to comfortably maintain a relationship long enough to raise a child.
arildno
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Oct25-12, 05:53 AM
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Quote Quote by Khantazm View Post
So, possibly I'm looking for the explanation according to Richard Dawkins, but I'd welcome all points of view. Why do women dress more brightly (when men still do the courting), while in other animals the sex that is courting is more bright (and loud)?
Do they, as a general historical rule??

Ryan_m_b
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Oct25-12, 06:52 AM
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Why are women more brightly colored (whereas in other animals males usually are)?

Quote Quote by Khantazm View Post
So, possibly I'm looking for the explanation according to Richard Dawkins, but I'd welcome all points of view. Why do women dress more brightly (when men still do the courting), while in other animals the sex that is courting is more bright (and loud)?
I don't agree that as a general rule across all human societies women dress up and men pursue. Is there any literature on this?
Darwin123
#5
Oct25-12, 09:13 AM
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Quote Quote by Khantazm View Post
So, possibly I'm looking for the explanation according to Richard Dawkins, but I'd welcome all points of view. Why do women dress more brightly (when men still do the courting), while in other animals the sex that is courting is more bright (and loud)?
I conjecture that it has something to do with the way that chromosomes determine sex. In animals where the gender is determined by the chromosomes, a pair of sex chromosomes determines the gender of the individual. There is usually one sex chromosome that is very small which the other sex chromosome doesn’t cross with. I’ll call that the unsocial chromosome. The other sex chromosome is large and tends to cross with other sex chromosomes like it. I’ll call that the social chromosome.

One gender has a matched set of sex chromosomes, which is called the homozygous gender. By matched, I mean that it has a pair of social chromosomes. The other gender has a mismatched set of chromosomes, which is called the heterozygous gender. By mismatched, I mean that it has one social chromosome and one unsocial chromosome.

The more ornamented gender is usually the heterozygous gender. I conjecture that is due to natural selection on the gene level. If two copies of the same gene are in the same individual, then the genes can augment each other. Therefore, genes in the social chromosome have a fitness incentive to pair with genes in another social chromosome. So genes that make ornamentation and which make the attraction toward the ornamentation have a better chance to survive than genes that don’t attract the corresponding chromosome.

Mammals are different from birds. In mammals, the male is the heterozygous gender. The male has an XY pair of sex chromosomes, and the female has an XX pair of chromosomes. Among mammals, the female tends to be the more ornamented gender. In birds, the female is the heterozygous gender. The male has a WW pair of sex chromosomes, and the female has a ZW pair of sex chromosomes. Among birds, the male tends to be the more ornamented gender. In both cases, the homozygous gender is the more oriented.

There are some other animals where the male is the homogenous gender. It appears to me that the homogenous gender tends to be the more ornamented.

I don't remember where I heard this conjecture. It may have been from Richard Dawkins, but I am not sure. In any case, it is a "gene centric" conjecture. The idea is that the genes in chromosomes that cross over to other chromosomes are more likely to be beneficial to copies of themselves.



Here are some links associated with sex chromosomes. The first presents the hypothesis that I just stated, although it doesn’t go into it in great detail.

http://www.ucl.ac.uk/mank-group/imag...DosageComp.pdf
“Is it possible that in ZW taxa, where the sex-determination system is predicted to favor the evolution of exaggerated male ornaments through female choice (e.g., birds and butterflies: Reeve and Pfennig 2003; Kirkpatrick and Hall 2004; Albert and Otto 2005), incomplete dosage compensation has enabled differential gene expression in males and females of other Z-linked loci important in sexual dimorphism to occur? To date, there are no data available linking gene expression levels of such sexually selected traits in butterflies and birds to examine this possibility.”



This link just says that in most animals other than mammals, the male is the homogenous gender.

http://en.wikipedia.org/wiki/Sex-determination_system
“The ZW sex-determination system is found in birds, reptiles, some insects and other organisms. The ZW sex-determination system is reversed compared to the XY system: females have two different kinds of chromosomes (ZW), and males have two of the same kind of chromosomes (ZZ). In the chicken, this was found to be dependent on the expression of DMRT1.[22] In birds, the genes FET1 and ASW are found on the W chromosome for females, similar to how the Y chromosome contains SRY.[11] However, not all species depend upon the W for their sex. For example, there are moths and butterflies that are ZW, but some have been found female with ZO, as well as female with ZZW.[20]”
arildno
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Oct25-12, 10:36 AM
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Quote Quote by Ryan_m_b View Post
I don't agree that as a general rule across all human societies women dress up and men pursue. Is there any literature on this?
Indeed.
In strongly patriarchal societies, like current islamist regimes, or ancient Rome, the women are, in their PUBLIC appearance to be kept in intentionally drab clothing.

It is, by the way, my personal opinion that the (relatively speaking) humungous, exposed penes of the human males have developed in this way, as result of sexual selection.
In particular, I believe that, because there are numerous physical disadvantages with exposed testes and penis, and that this vulnerable trait cannot have been developed unless there was a strongly selective advantage for this peculiarity of the human male.
Khantazm
#7
Oct25-12, 12:38 PM
P: 27
Thanks, Darwin123, although you lost me there a bit (maybe not a bit) with my layman background. I think I got the gist of it. It appears rather far-fetched, even though I'm partial to the gene-centric view of evolution. I think I'll have to ponder it.

As for generalizations, I do appear to recall (or maybe confabulate) that whoever it was he spoke about ornamentation in modern European women specifically... So... Yeah, if it's the XY thing it's long been overridden by culture... So I could have met it in a less biology-related book by that author. It could even have something to do with feminism.

P.S. Darwin123, you don't happen to have a pop-sci version of your conjecture?
nitsuj
#8
Oct25-12, 12:40 PM
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Quote Quote by arildno View Post
It is, by the way, my personal opinion that the (relatively speaking) humungous, exposed penes of the human males have developed in this way, as result of sexual selection.
In particular, I believe that, because there are numerous physical disadvantages with exposed testes and penis, and that this vulnerable trait cannot have been developed unless there was a strongly selective advantage for this peculiarity of the human male.


Are you joking?
arildno
#9
Oct25-12, 12:46 PM
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Quote Quote by nitsuj View Post


Are you joking?
Nope.
The development of the male penis in the human being is completely anomalous relative to every other primate.
In particular in the features of its relative bigness (a gorilla male has, typically, a penis size of whopping..7 centimetres) and exposedness (most have them protected within their bodies, rather than dangling about).

Thus, it seems to me analogous to the male peacock's silly, but ostentatious feathers.
Darwin123
#10
Oct25-12, 03:09 PM
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Quote Quote by arildno View Post
Nope.
The development of the male penis in the human being is completely anomalous relative to every other primate.
In particular in the features of its relative bigness (a gorilla male has, typically, a penis size of whopping..7 centimetres) and exposedness (most have them protected within their bodies, rather than dangling about).

Thus, it seems to me analogous to the male peacock's silly, but ostentatious feathers.
Here is a study where my conjecture is put to the test, and fails. Ahh well, they are only fish.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1560031/
“Theory predicts that the mechanism of genetic sex determination can substantially influence the evolution of sexually selected traits. For example, female heterogamety (ZZ/ZW) can favour the evolution of extreme male traits under Fisher's runaway model of sexual selection. We empirically test whether the genetic system of sex determination has played a role in the evolution of exaggerated male ornaments in actinopterygiian fishes, a clade in which both female-heterogametic and male-heterogametic systems of sex determination have evolved multiple times. Using comparative methods both uncorrected and corrected for phylogenetic non-independence, we detected no significant correlation between sex-chromosome systems and sexually selected traits in males. Results suggest that sex-determination mechanism is at best a relatively minor factor affecting the outcomes of sexual selection in ray-finned fishes.”

Okay, I am now prepared to take your conjecture more seriously.

If the large size of the human species is an ornament for attracting attention, then I believe that its purpose is to intimidate other males more than to attract females. I notice that men tend to refer to their penis size when they discuss aggression. Men compare penis sizes when preparing for conflict.
I conjecture that penis size is not very important to most women. There may be women who prefer large penis sizes. However, they are not quite as vocal about it as men who are preparing for a fight.

Here is an article that says that many sexual ornaments have a dual use: to attract females and to signal aggression. It says that generally the aggression signal is often more important in a dual use ornament. I keep on hearing words for penis associated with violence rather than sex.

Here is a link proposing this conjecture.

http://cprg.psy.unipd.it/pdf/BERGLUN...urnLjnnSoc.pdf
“Moreover, our model may more satisfyingly than traditional ones explain how trait honesty and trait genetic variance are maintained: theoretical and empirical evidence suggests that such honesty and variation are more easily maintained under male-male competition than under female choice.”
arildno
#11
Oct25-12, 03:30 PM
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One of the penis theories in great vogue is the "semen displacement theory", in that length of the penis and the critical shape of the penis head is highly effective in scooping out foreign, competitive semen from the vagina.
See Scientific American on this:
http://www.scientificamerican.com/ar...of-the-phallus

Note that this theory is a direct competitor to the sexual display/selection theory, in that it claims to substantiate a direct natural selection theory, although I don't think it explains very well the exposed vulnerability of the human penis&testes.
arildno
#12
Oct25-12, 03:40 PM
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"Here is an article that says that many sexual ornaments have a dual use: to attract females and to signal aggression. It says that generally the aggression signal is often more important in a dual use ornament. I keep on hearing words for penis associated with violence rather than sex. "

Now, slapping each other with one's own flaccid variety hardly brings about injuries in a competitor.
However, if penis size can be seen to be roughly correlated with, say, muscle mass or threshold of pain, then its display function could have a rather unveiled threat component as well.
Bobbywhy
#13
Oct25-12, 07:20 PM
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Quote Quote by arildno View Post
Thus, it seems to me analogous to the male peacock's silly, but ostentatious feathers.
In defense of the male peacock, it so happens that their “silly, but ostentatious feathers" form a parabolic reflector that directs infrasonic thrums below 20 Hz generated by the male for long distances through thick shrubbery. Most probably this adaptation has evolved to summon more potential mates using infrasound.

http://www.sciencenews.org/view/gene..._make_a_rumble

Cheers,
Bobbywhy
Khantazm
#14
Oct26-12, 12:26 AM
P: 27
^That's fascinating.

Continuing with cock-slapping, humans appear to be the only mammals without a bone in the penis... Which somehow contributed to the hypothesis of sexual selection of penis characteristics last time I read about it.
ImaLooser
#15
Oct26-12, 01:50 AM
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Quote Quote by Khantazm View Post
So, possibly I'm looking for the explanation according to Richard Dawkins, but I'd welcome all points of view. Why do women dress more brightly (when men still do the courting), while in other animals the sex that is courting is more bright (and loud)?
In the case of birds the female is very vulnerable during nesting and has to stay hidden, so bright colors would be a big disadvantage. Fish are sometimes this way too.

With other animals the color seems to be the same.

With humans it depends on culture. Sometimes men are the bright ones. But usually women are more colorful. I'd say it because the men usually chooses the woman, and she needs to attract attention. Predation is not a problem these days.
arildno
#16
Oct26-12, 04:13 AM
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Quote Quote by Bobbywhy View Post
In defense of the male peacock, it so happens that their “silly, but ostentatious feathers" form a parabolic reflector that directs infrasonic thrums below 20 Hz generated by the male for long distances through thick shrubbery. Most probably this adaptation has evolved to summon more potential mates using infrasound.

http://www.sciencenews.org/view/gene..._make_a_rumble

Cheers,
Bobbywhy
Absolutely fascinating to see a direct adaptive advantage of this!
I have bought into the rather simplistic, but traditional explanation of sexual selection here, that the strongest male is he who can cope with the strongest handicap.

Great that you offered me a new perspective here!
Khantazm
#17
Oct26-12, 11:30 AM
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Quote Quote by ImaLooser View Post
With humans it depends on culture. Sometimes men are the bright ones. But usually women are more colorful. I'd say it because the men usually chooses the woman, and she needs to attract attention. Predation is not a problem these days.
It's counter to reality like this. In the cultures, where the man has the most power to choose, women are the drabbest (Islam, say). Whereas liberated European women, who don't bend that much to the man's will, dress much brighter... Although in societies and strata of those societies which are the most liberated men catch up to women... Hm... Okay, I think I've grabbed a thread and I'm not sure I don't even need to show the end of it, because it seems pretty obvious. I'll dare but a hint: in societies where men have the most power they don't like women to challenge it so they enforce female drabness so women aren't prominent <end hint>.
256bits
#18
Oct27-12, 05:45 AM
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Quote Quote by Khantazm View Post
It's counter to reality like this. In the cultures, where the man has the most power to choose, women are the drabbest (Islam, say). Whereas liberated European women, who don't bend that much to the man's will, dress much brighter... Although in societies and strata of those societies which are the most liberated men catch up to women... Hm... Okay, I think I've grabbed a thread and I'm not sure I don't even need to show the end of it, because it seems pretty obvious. I'll dare but a hint: in societies where men have the most power they don't like women to challenge it so they enforce female drabness so women aren't prominent <end hint>.
You have to answer the question whether human females dress to impress males to aquire a mate or other females to gain status, or to just impress themselves. In can also be argued that men in certain societies initiate and the woman choose. In other societies, the family will do the chosing and acceptance of a suitable mate for the prospective young male and female.
With regards to your hint, is your argument that drab clothing is actually a suppression of females within society rather than a suppression of vanity - one could also argue that with all members of a society being dressed in a comparable attire, it would be more difficult to express an attraction to a particular individual based solely on looks.

In addition, men and woman both enforce suitable attire, whether it be drab or colorful, with the verb enforce having a different strength level depending upon which society and culture you are a member of.


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