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Psychology of Human Nature... are these really "truths?

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quex
From PsychologyToday.com:

Ten Politically Incorrect Truths About Human Nature

There's an obvious flaw in the "blonde hair" argument -- blond hair doesn't appear in many ethnicities, so why would men there have developed a preference for it? Take Japan, for example. Almost all Japanese, barring those who manifest some recessive gene, are born with hair in a narrow color range of very dark brown to black. As early as the Tale of Genji (world's first novel, BTW -- trivia for a quiz show), men from the upper class and presumably all social strata in Japan favored a woman with extremely long, straight, dark black hair. Similarly, dark eyes were a plus. (I'm intrigued by the pupil-expansion observation... gonna try this the next time I meet a baby.) Even now, while blonde hair and colored contacts are something of a novelty for Japanese women to play with in society, light hair and eyes are not becoming for a bride.

Either the argument is blatantly flawed, or the "human nature" detailed therein only considers the western cultures.
Indi
quex wrote:
From PsychologyToday.com:

Ten Politically Incorrect Truths About Human Nature

There's an obvious flaw in the "blonde hair" argument -- blond hair doesn't appear in many ethnicities, so why would men there have developed a preference for it? Take Japan, for example. Almost all Japanese, barring those who manifest some recessive gene, are born with hair in a narrow color range of very dark brown to black. As early as the Tale of Genji (world's first novel, BTW -- trivia for a quiz show), men from the upper class and presumably all social strata in Japan favored a woman with extremely long, straight, dark black hair. Similarly, dark eyes were a plus. (I'm intrigued by the pupil-expansion observation... gonna try this the next time I meet a baby.) Even now, while blonde hair and colored contacts are something of a novelty for Japanese women to play with in society, light hair and eyes are not becoming for a bride.

Either the argument is blatantly flawed, or the "human nature" detailed therein only considers the western cultures.

Not necessarily. The article describes a mechanism and then gives specific examples. If those specific examples only apply to peoples that evolved in one section of the world, why does that make the entire mechanism flawed?

Of course the desire for blonde hair is not universal. You mentioned Japanese, but i seriously don't imagine it would apply to central African tribes of black people or Arabs in the Middle East either. But that doesn't invalidate the underlying mechanism. You simply have to consider the evolutionary background of those people rather than the evolutionary background of modern Europeans.

For example, consider the Japanese you mentioned. In their case, blonde hair might not be seen as a sign of health at all because it was so rare so early in their genome. By contrast, it may have been associated with anomalous genetic patterns, like albinos, or it may have been considered to be similar to grey hair or something. i would suspect that the Japanese look for other indications of the same thing that blonde hair signifies to Europeans. For example, perhaps Japanese prefer fine hair as opposed to coarse - because fine hair is a better indicator of general health than coarse hair.

Similarly for the eyes. Eyes with larger pupils look more child-like than eyes with smaller pupils, and dark eyes make the pupils look huge (look at cartoons, which use this effect to exaggerate childishness - see the image below). So again, it creates an appearance of youth.


You see? Even though the specific identifiers change, the underlying idea is the same. You'll note that the article even mentions that blonde hair became prevalent probably because bulky cold-weather clothing made it an easily spotted indicator. The same was perhaps not true in the ancestors of Japanese, who probably evolved in the tropical regions of south-eastern Asia.
Gagnar The Unruly
Perhaps, but I think most people might be surprised at the level of gene flow among populations. I find it difficult to believe that natural selection is able to maintain genetic differences in sex cue identification across our species. I think it's a lot more likely that our fascination for blondes is cultural, and has little to no basis in evolution. That's a plausible and simple alternative to the evolutionary hypothesis, which I regard as pseudoscientific cold-reading. I think our preference for blones comes from an old-fashioned sense that bloneness denotes purity. The cultural ancestors of Westerners valued fair skin, fair hair, and fair eyes in women because they had schemas saying that light colors were good, and dark colors evil. Blonde women were fairer - i.e. more innocent and virtuous. Is there any reason to believe for evolutionary reasons that blonde women are more virtuous? Hardly.

In general, it's good to be wary of statements that overemphasize the role of genetic evolution in maintaining human social differences. They are often founded on rather shaky premeses. I would take issue, for example, with the premise that blonde women, if they are more attractive, are able to maintain a higher reproductive output than brunettes. In my experience, it has seemed that most people who so desire find a way to reproduce. When the opportunity for sex presents itself, I doubt that men now or ever are going to put on the brakes if the hair color is off. Also, in the pre-contraceptive days, women were exposed to far fewer sexual encounters than they are now. A woman without access to contraceptives would only need to have sex a relative handfull of times in order to meet her full reproductive capacity. Even if, back in the day, blondes did have more fun, they might not have enjoyed a fecundity advantage over brunettes.
Indi
Gagnar The Unruly wrote:
Perhaps, but I think most people might be surprised at the level of gene flow among populations. I find it difficult to believe that natural selection is able to maintain genetic differences in sex cue identification across our species.

Why? Different evolutionary populations have different physical features. Doesn't it naturally follow from that that they must have different means of identifying attractive mates? Or do you think that the fact that East Asian populations do not look like Central African populations is a fluke?

Given the fact that different evolutionary populations are distinctly physically different, isn't that already conclusive evidence that they must have different standards for selecting partners and that those selection standards must be identifiable by the dominant traits that exist? If a population has 95% dark hair... doesn't that automatically imply that dark hair is selected for somehow? And if there is no survival benefit to dark hair, doesn't it also naturally follow that the selection pressure is due to the desirability it gives a breeding partner?

Gagnar The Unruly wrote:
I think it's a lot more likely that our fascination for blondes is cultural, and has little to no basis in evolution. That's a plausible and simple alternative to the evolutionary hypothesis, which I regard as pseudoscientific cold-reading.

Mmm, careful.

First, any conclusions drawn about evolutionary selection factors are necessarily post hoc. That can't be helped. However, that doesn't make it completely arbitrary. After we come up with an evolutionary explanation for a characteristic, we can test it... somewhat. For example, once we decide that men are larger than women because of the fact that we are a polygynous species, and explain that by the fact that larger men could acquire more mates (by beating off smaller men) and support more mates (by simply being bigger and stronger), then we can compare other polygynous species to see if there is a correlation between the degree of polygyny and the size differential between the sexes. i can say that large, dark eyes give humans the impression of an infant because we see the same evolutionary trend in domesticated dogs - dogs with... well, puppy-dog eyes... were selected for by human breeders because they were "cute" - the same mechanism can be applied to large, dark eyes. It's not proof, but it's certainly not arbitrary guesswork.

Second... there is nothing "scientific" about saying "it's the culture", because that doesn't answer any questions at all. It simply defers them. Ok, let's say i bought your claim that people selected for blue eyes because the culture deemed blue eyes to be desirable. The next logical question is... why? Why does the culture say blue eyes are desirable? You'll find that "culture" is not an answer for anything, because "culture" is a product of the population and the environment. To explain the reason for a cultural preference for blue eyes, you have to go back to why the members of the population prefer blue eyes. If you then turn around and say that the members of the population prefer blue eyes because the culture says their desirable... well, you can see how that's a game that will never end. Eventually, you're going to have to come back to evolutionary selection pressures.

Gagnar The Unruly wrote:
I think our preference for blones comes from an old-fashioned sense that bloneness denotes purity. The cultural ancestors of Westerners valued fair skin, fair hair, and fair eyes in women because they had schemas saying that light colors were good, and dark colors evil. Blonde women were fairer - i.e. more innocent and virtuous. Is there any reason to believe for evolutionary reasons that blonde women are more virtuous? Hardly.

But of course, that answers nothing. Why do Westerners' ancestors prefer light colours in their mates and not Central Africans' ancestors? Do Central Africans believe that darkness is good and light is evil? No, they don't. In fact, the cultural belief that bright and shiny = good is almost universal. So what happened between Europe and Central Africa? Your answer explains nothing.

Besides, your rationale doesn't really stand up when you consider the fact that most of these genetic differences had been established loooooong before any of the populations could communicate the ideas of goodness and virtue... and in fact, very likely long before they actually had the intellectual wherewithal to conceive of "good vs. bad" in that sense.

Gagnar The Unruly wrote:
In general, it's good to be wary of statements that overemphasize the role of genetic evolution in maintaining human social differences. They are often founded on rather shaky premeses. I would take issue, for example, with the premise that blonde women, if they are more attractive, are able to maintain a higher reproductive output than brunettes.

Whoa whoa whoa. That's completely wrong-headed.

Let me see if i can explain why. Go back to an age where the infant mortality was extremely high - obviously these kinds of selection pressures are meaningless today when any brain-dead moron can breed like a rabbit and know that virtually every single one of their kids will grow up to be just as prodigious.

Now imagine you had a village of 10 guys and 10 girls, and 3 of the girls are blonde. One guy in that village is the big chief - he is bigger and stronger than everyone one else, and what he wants... goddammit, he will get. He gets first dibs on any crops raised or any game hunted. If there's not enough food for everyone... he and his aren't going to be the ones to starve. That chief decides he wants 5 mates, and seeing as how blondes are more desirable, he gets the 3 blondes and two others. Then, of course, he favours the 3 blondes sexually more often than the other 2 - because they're "prettier". Already there will be more children from those 3 blondes than the non-blondes.

But what about the other 5 girls? Well, they get distributed amongst the rest of the men somehow - so at least 5 guys are dying off without children (assume no sharing, because that just complicates things). But remember, the infant mortality rate is very, very high. Those 5 girls who aren't favoured by the chief... they're not going to produce nearly as many offspring that go on to breed as the 5 he took.

So! Of the girls in the village, the blondes will have a slight breeding advantage, because they will be favoured by the chief, and will have a lower infant mortality rate. Remember your evolutionary bio - a genetic advantage merely that allows three viable offspring instead of two will become dominant in just a couple of generations.

It doesn't take much to turn a very slight genetic advantage into a massive change in the population. So, frankly, yes. If blondes are even slightly more attractive than brunettes, they would have had a much, much higher reproductive rate over a few generations.

Gagnar The Unruly wrote:
In my experience, it has seemed that most people who so desire find a way to reproduce. When the opportunity for sex presents itself, I doubt that men now or ever are going to put on the brakes if the hair color is off.

It's not a matter of men saying no to a brunette. It's a matter of men - when freely able to choose between a blonde and a brunette - always choosing the blonde. That's all it takes.

Your experience is not relevant. We live in an age where there is no real selection pressure of this type. Anyone that wants to breed, can. They may not get their first pick partner, but anyone can breed. And any child conceived has an enormously high chance of survival.

Gagnar The Unruly wrote:
Also, in the pre-contraceptive days, women were exposed to far fewer sexual encounters than they are now.

Excuse me? ^_^;

Gagnar The Unruly wrote:
A woman without access to contraceptives would only need to have sex a relative handfull of times in order to meet her full reproductive capacity. Even if, back in the day, blondes did have more fun, they might not have enjoyed a fecundity advantage over brunettes.

No, sorry, your reasoning is way, way off base.

Again, it's not just a matter of blondes getting laid more. It's a matter of the biggest and strongest men choosing blondes first. And the women will want to be chosen by these men, because they offer a significantly higher chance of their offspring growing to reproduce themselves. Even if blondes and brunettes got laid just as often, and had exactly equal amounts of babies, the blondes would still be selected for if they were with mates that increased the chances of the child's survival. That's the key you're missing. You're completely forgetting about infant mortality.
Gagnar The Unruly
Indi,

The point is, I don't think selection is responsible for those differences. There are four factors that can influence the allele frequency in human populations: 1) natural selection, 2) sexual selection, 3) genetic drift, and 4) demographic processes/immigration.

Given the knowledge that people look different, one cannot reasonably deduce that they also have different sexual cues. People often mistakenly assume that we view as most attractive the organisms with the greatest fitness. This certainly can be the case, but it is also not necessarily the case, and there are many instances in nature where sexual selection acts to enhance traits that are otherwise detrimental for the survival of the affected organism. Sexual selection can initiate mate-choice arms races that drive entire populations towards extinction by amplifying expression of traits that make survival much more difficult. More often, sexual selection may influence traits that have little effect on natural fitness (e.g. certain frog vocalizations).

Regarding the difference in East Asians vs. Central Africans, fluke is too strong a word, though I question the importance of sexual selection in maintaining those differences. I would say that some of the difference is due to natural selection, and most of the difference is due to genetic drift and historical immigration patterns. Not only that, but I would say that our perception of the differences are culturally influenced. Africa is far from a homogenous environment, though most Westerners would say that Africans from different regions look more or less the same. An African would have a different perspective. Not only that, but there is probably considerable niche overlap between a stone-age American lifestyle as a stone-age African one. Why, then, is there so little phenotypic similarity between native Americans and native Africans? Probably, the answer has a lot to do with the patterns of human movement combined with random heterogeneities introduced by genetic drift.

Is it possible that sexual selection plays a role in maintaining population differences? Of course, but I can give a few reasons to support my skepticism. The first is my own experience with my own inner nature. I don't think I have trouble finding women of different ethnic backgrounds than me attractive. Also, I don't believe that researchers have actually found much evidence that heritable mate selection preferences are important for humans. I believe it's been shown that attractiveness has more to do with how well people match our schemas (more matching = more attractive), making sex-selection a culturally-influenced and not a heritable trait. One other important point: a trait with large phenotypic plasticity (such as our perception of attractiveness) is a trait that is hard for selection to act on. This is because two differing genotypes may have the same phenotypic expression. An example of human plasticity in this case would be hair re-coloring. There can't be much selection for blondness, if all the brunettes are dying their hair!

I would argue that increased phenotypic plasicity lowers the influence of selective forces on a population, making genetic drift and immigration/demographic processes more important. High levels of phenotypic plasticity are de facto in human populations. We are strongly influenced by our physical and cultural environment. I think the burden of proof is on the person claiming that a particular trait is influenced by selection, rather than by the other mentioned factors.

A few other points: some Africans do believe that dark is good and light is evil, at least in certain context. The color white is associated with evil forces and with death, and white paint is frequently used during rituals and during warfare.

Indi wrote:
Now imagine you had a village of 10 guys and 10 girls, and 3 of the girls are blonde. One guy in that village is the big chief - he is bigger and stronger than everyone one else, and what he wants... goddammit, he will get. He gets first dibs on any crops raised or any game hunted. If there's not enough food for everyone... he and his aren't going to be the ones to starve...


I'm not going to answer you point-by-point here, except to say that I don't think your thought experiment is particularly good at emulating any real culture that has ever existed, pre-industrial or otherwise. In fact, one doesn't have to go too far into the past to go to a time in which the cultures of the world were almost uniformly matriarchal, and I don't even know where that leads this discussion.
newolder
What does one call a blonde with two brain cells?

Pregnant.

(Coat, got... ) Rolling Eyes
Indi
Gagnar The Unruly wrote:
Given the knowledge that people look different, one cannot reasonably deduce that they also have different sexual cues. People often mistakenly assume that we view as most attractive the organisms with the greatest fitness. This certainly can be the case, but it is also not necessarily the case, and there are many instances in nature where sexual selection acts to enhance traits that are otherwise detrimental for the survival of the affected organism.

That is not entirely true. It is true that one does not necessarily select the most environmentally "fit" sexual partner (where fitness is measured by natural selection pressures or whatever). But one does select the partner that they perceive to be the most "fit".

Take colourful birds, for example. Obviously bright and garish colours do not really make for much "fitness" from a natural selection perspective - it's like a flashing bullseye for predators. So why would any bird select a partner that's bright and flashy, when a duller-coloured partner would probably produce children with greater longevity? Answer: because sickly birds are usually dull coloured compared to healthy birds.

It's the same with the frogs that you mention. i am not familiar with frogs, but i would bet that healthy, strong frogs croak louder/longer/whatever than sickly, weak frogs.

And again, it's the same with blondes. What fitness advantage does blonde hair have? Probably none. Therefore the fact of its existence is probably due to sexual selection.

Now, you offered two other possibilities: phenotype drift and population mobility. Now, population mobility can explain how foreign characteristics can be added to a population, but it can't explain why any given population has a characteristic that is dominant within it and not elsewhere, so you can rule that out. But what about simple genetic drift? Well, in some cases, that's rather hard to rule out, but in others, it's trivial. Take blonde hair for example. Blonde hair is a recessive trait. The chances of it being dominant in a population randomly are ludicrously small over enough time. Therefore, it must have been selected for somehow. Naturally? Hardly. Thus, it must be selected for sexually.

Gagnar The Unruly wrote:
A few other points: some Africans do believe that dark is good and light is evil, at least in certain context. The color white is associated with evil forces and with death, and white paint is frequently used during rituals and during warfare.

But that still doesn't address the issue i raised. Did Central African tribes become predominantly black because of that belief? That sounds rather implausible to me. The opposite sounds more likely... that cultural belief came into being because of an existing bias toward darker-skinned mates.
quex
*golf clap for Gagnar*

I knew there was a good reason I liked you so much. ^_^
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