Sexy parents produce sexy daughters (but not sons)

A very interesting new paper in Animal Behaviour regarding the inheritance of masculinity/famininity and attractiveness. On the left are composites of 10 attractive parents and their daughters, and on the right composites of 10 unattractive parents and their daughters.

Not surprisingly, the attractive female looks similar to another facial composite in a recent study on facial correlates of sociosexuality by authors from the same institution (University of St. Andrews in the UK).

The difference between Fisherian runaway selection and "good genes" theory -mentioned below- is that in the former, a "sexy" trait is selected even though it has no adaptive value (such as the peacock's tail), while in the latter the latter the "sexy" trait is that which signifies good genetic qualities (e.g. health).

From the paper:

Our findings are supportive of both Fisherian processes and good genes theory. Both parents contributed to the attractiveness and femininity of daughters. We found that daughter's attractiveness was predicted independently by father's attractiveness and mother's femininity (and therefore, by default, mother's attractiveness). Fisherian selection processes would suggest that men have evolved preferences for sexually dimorphic facial characteristics in opposite-sex partners, and through human evolution these preferences have increased the frequency of feminine facial characteristics such as a slender chin, full lips and large eyes in women. Good genes theory predicts the same finding, although it suggests that feminine facial characteristics must by definition signal good quality, including possible cues to immunocompetence, fertility, youthfulness, health and perhaps even maternal tendencies

...

We are perplexed as to why we did not find any evidence for the inheritance of attractiveness in males, through either the female or male parent. Attractiveness, by its own definition, should be sexy, and while we found evidence for sexy parents–sexy daughters, we did not find the parallel in male offspring. While masculine dads produced masculine sons, in this study, sexy parents did not produce sexy sons.

UPDATE : For a possible solution to this paradox, see next post.

Animal Behaviour doi: 10.1016/j.anbehav.2008.07.031

Sexy sons and sexy daughters: the influence of parents' facial characteristics on offspring

R. Elisabeth Cornwell, and David I. Perrett

Abstract

Choosing a mate to maximize fitness underlies all sexual selection theories. Key to understanding mate choice is the inheritance of particular traits. Using family photos, we evaluated the predictions made by sexual selection theories for human mate choice concerning the inheritance of facial characteristics and assortment in facial appearance of parents. We found that both fathers' and mothers' attractiveness predicted the facial attractiveness of daughters: ‘sexy daughters’. Fathers and sons were related to each other in facial masculinity but not attractiveness, providing only partial evidence for ‘sexy sons’. Mothers and sons did not relate in masculinity–femininity; neither did fathers and daughters. Parents were similar in attractiveness but masculine men were not partnered to feminine women. Our findings support some predictions of Fisherian selection processes and ‘good genes’ theory but are less consistent with ‘correlated response theory’ and the immunocompetence handicap principle.

Link

Social perception of obesity

Caption for figure:

1. Lean (L - narrow shoulders, thin torso and extremities, knee and elbow joints thicker than thy and arm diameter). 2. Muscular (M – Broad shoulders, curved extremities, chest and abdominal muscles shown, thy and arm diameters greater than knee and elbow joints). 3. Slightly fat and feminine (F – rounded shoulders, cylindrical extremities). Each of the three body forms was represented with (designated by +) and without (−) abdominal obesity as shown in rows. The sequence of these figures was randomized during the test and the figures were labeled serially by alphabets.

From the paper:

hysical characters were associated with the appropriate body forms as expected. The physical traits strong, rough and tough and physically aggressive were associated with the muscular non-obese [M−] figure. Lethargic was associated with F+. Disease prone was significantly associated with L− on the one hand and F+ on the other indicating that people negatively associate both the extremes with health. The trait swift was also strongly associated with L−. The traits that are not obviously physical were also strongly associated with certain body forms. Brave, conscious about looks, influential, dominating, status conscious, modern and confident were associated with M−; physical risk avoider, money minded, political, rich, stupid, selfish and greedy were associated most strongly with F+; friendly, intelligent, methodical, business risk avoider, successful, loving, kind, and honest were associated with F−; and L− was the commonest choice for swift, physical risk avoider, talkative and the trait depressed was associated with L+ [table 1].

Link to Table 1.

PLoS ONE doi: 10.1371/journal.pone.0003187

Obesity as a Perceived Social Signal

Manasee Mankar et al.

Abstract

Fat accumulation has been classically considered as a means of energy storage. Obese people are theorized as metabolically ‘thrifty’, saving energy during times of food abundance. However, recent research has highlighted many neuro-behavioral and social aspects of obesity, with a suggestion that obesity, abdominal obesity in particular, may have evolved as a social signal. We tested here whether body proportions, and abdominal obesity in particular, are perceived as signals revealing personality traits. Faceless drawings of three male body forms namely lean, muscular and feminine, each with and without abdominal obesity were shown in a randomized order to a group of 222 respondents. A list of 30 different adjectives or short descriptions of personality traits was given to each respondent and they were asked to allocate the most appropriate figure to each of them independently. The traits included those directly related to physique, those related to nature, attitude and moral character and also those related to social status. For 29 out of the 30 adjectives people consistently attributed specific body forms. Based on common choices, the 30 traits could be clustered into distinct ‘personalities’ which were strongly associated with particular body forms. A centrally obese figure was perceived as “lethargic, greedy, political, money-minded, selfish and rich”. The results show that body proportions are perceived to reflect personality traits and this raises the possibility that in addition to energy storage, social selection may have played some role in shaping the biology of obesity.

Link

Masculine vs. Feminine Walk

Walk this way? Masculine motion seems to come at you, while females walk away

You can tell a lot about people from the way they move alone: their gender, age, and even their mood, earlier studies have shown. Now, researchers reporting in the September 9th issue of Current Biology, a Cell Press publication, have found that observers perceive masculine motion as coming toward them, while a characteristically feminine walk looks like it's headed the other way.

Such studies are done by illuminating only the joints of model walkers and asking observers to identify various characteristics about the largely ambiguous figures.

"It's a really interesting thing," said Rick van der Zwan of Southern Cross University in Australia. "If you look at someone with just their joints illuminated when they aren't moving, it's difficult to tell what it is you are looking at. But as soon as they move, instantaneously, you can tell that it's a person and perceive their nature. You can tell if it's a boy or a girl, young or old, angry or happy.… You can discern all these qualities about their state, affect, and actions with no cues at all about what they look like—with no form at all, just motion."

Many previous studies of biological motion perception have relied on male figures as models, van der Zwan said. One of those earlier studies had noticed an interesting phenomenon: even though you can't really tell whether a so-called point-light figure is facing toward you or away, people seemed to perceive those figures always as facing in their direction.

Now, van der Zwan and his colleagues show that this isn't always true.

In their study, they allowed people to observe point-light figures representing a continuum from an extremely "girly girl" to a "hulking male." At the halfway point in between was a gender-neutral walker that observers judged as male half the time and female half the time.

Their results showed that walking male figures did indeed appear to face toward you. Female figures, on the other hand, seemed as though they faced away. The results are the first to show a link between the perception of gender from biological motion cues and the perception of orientation.

That same pattern emerged regardless of the gender of the person watching, a finding that van der Zwan considers an important clue about the behavior.

"Our data suggest that biological motion is an important cue for social organisms trying to operate in environments where other cues as to the actions or intentions of other organisms may be ambiguous," the researchers wrote. "Whilst the precise role of local cues in mediating these effects requires further explication, it is tempting to speculate that the orientation biases reported here reflect the development of perceptual mechanisms that weigh in the probable cost of misinterpreting the actions and intentions of others. For example, a male figure that is otherwise ambiguous might best be perceived as approaching to allow the observer to prepare to flee or fight. Similarly, for observers, and especially infants, the departure of females might signal also a need to act, but for different reasons."

I wonder what these different reasons are. A hint from our closest relatives:

Although chimpanzees virtually never adopt face-to-face positions, bonobos do so in one out of three copulations in the wild.

The "infant" explanation probably relates to a tendency to cry when a mother is perceived as leaving.

It will be interesting to see if ethnicity/race/social class can also be perceived by walking style. 

See also Walking speed in different cities.

Current Biology doi:10.1016/j.cub.2008.06.054

Correlated changes in perceptions of the gender and orientation of ambiguous biological motion figures

Anna Brooks et al.

The sensitivity of the mammalian visual system to biological motion cues has been shown to be general and acute [1], [2] and [3]. Human observers, in particular, can deduce higher-order information, such as the orientation of a figure (which way it is facing), its gender, emotional state, and even personality traits, on the basis only of sparse motion cues. Even when the stimulus information is confined to point lights attached to the major joints of an actor (so-called point-light figures), observers can use information about the way the actor is moving to tell what they are doing, whether they are a male or female, and how they are feeling [4], [5] and [6]. Here we report the novel finding that stimulus manipulations that made such walkers appear more female also had the effect of making the walkers appear more often as if they were walking away from rather than towards observers. Using frontal-view (or rear-view) point-light displays of human walkers, we asked observers to judge whether they seemed to be walking towards or away from the viewing position. Independent of their own gender, observers reliably reported those figures they perceived to be male as looking like they were approaching (as reported in [7]), but those they perceived to be female as walking away. Furthermore, figures perceived to be gender-neutral also appeared more often, although not exclusively, to be walking towards observers.

Link

Balancing selection and homosexuality

The idea in this paper is that the genetic factors leading one to be homosexual also lead one to have higher mating success if he turns out to be heterosexual.

The use of "lifetime number of opposite sex sexual partners" as a stand-in for reproductive success is fairly problematic. It seems more likely that a couple that marries young with limited pre-marital experience will have a higher number of children than individuals who spend a lot of time having sex with multiple people (not to mention the risk to one's health from such behavior).

In my own opinion (see Beautiful Wives and Gay Sons) homosexuality is rooted in a side-effect of the expression of femininity-- or masculinity-enhancing traits in individuals of the wrong gender: if, e.g., a couple has an excess of "feminine" DNA between them, it may produce reproductively successful daughters but sons at higher risk for homosexuality. These genes are more successful (than average) in female bodies, and less than average in male ones: thus they are maintained in the gene pool.

There is a good case to be made, however, for a link between homosexuality and promiscuity. A certain lack of inhibition may be linked to the expression of the homosexual phenotype; this may explain why homosexuals tend to have more partners than average compared to heterosexuals. 

Evolution and Human Behavior doi: 10.1016/j.evolhumbehav.2008.07.002

Genetic factors predisposing to homosexuality may increase mating success in heterosexuals

Brendan P. Zietsch et al.

Abstract

There is considerable evidence that human sexual orientation is genetically influenced, so it is not known how homosexuality, which tends to lower reproductive success, is maintained in the population at a relatively high frequency. One hypothesis proposes that while genes predisposing to homosexuality reduce homosexuals' reproductive success, they may confer some advantage in heterosexuals who carry them. However, it is not clear what such an advantage may be. To investigate this, we examine a data set where a large community-based twin sample (N=4904) anonymously completed a detailed questionnaire examining sexual behaviors and attitudes. We show that psychologically masculine females and feminine men are (a) more likely to be nonheterosexual but (b), when heterosexual, have more opposite-sex sexual partners. With statistical modelling of the twin data, we show that both these relationships are partly due to pleiotropic genetic influences common to each trait. We also find a trend for heterosexuals with a nonheterosexual twin to have more opposite-sex partners than do heterosexual twin pairs. Taken together, these results suggest that genes predisposing to homosexuality may confer a mating advantage in heterosexuals, which could help explain the evolution and maintenance of homosexuality in the population.

Link

Women with high-pitched voices are more attractive

Perception. 2008;37(4):615-23.

The role of femininity and averageness of voice pitch in aesthetic judgments of women's voices.

Feinberg DR, DeBruine LM, Jones BC, Perrett DI.

Although averageness is preferred in auditory stimuli (eg music) and non-face objects (eg wristwatches), exaggerated feminine characteristics are preferred to averageness in female faces. To establish whether or not men prefer femininity in female voices to average characteristics, we conducted a correlational study (study 1) to assess the relationship between voice pitch and attractiveness ratings. We found a positive linear relationship between voice pitch and attractiveness ratings. In study 2 we manipulated pitch in women's voices with low (lower than average), average, and high (higher than average) starting pitches and gauged men's preferences. Men preferred women's voices with raised pitch for all levels of starting pitch. These findings suggest that men prefer high voice pitch to average voice pitch in women's voices.

Link

Facial masculinity

From LiveScience:

In the study, 854 male and female subjects viewed a series of male head shots that had been digitally altered to exaggerate or minimize masculine traits. The participants then answered questions about how they expected the men in the photos to behave.

Overwhelmingly, participants said those with more masculine features were likely to be risky and competitive and also more apt to fight, challenge bosses, cheat on spouses and put less effort into parenting. Those with more feminine faces were seen as good parents and husbands, hard workers and emotionally supportive mates [compare examples].

Despite all the negative attributes, when asked who they would choose for a short-term relationship, women still selected the more masculine looking men. Brad and George then would be picks for a brief romance, if not the long haul.

Personal Relationships
Volume 13 Issue 4 Page 451 - December 2006

Male facial masculinity influences attributions of personality and reproductive strategy

DANIEL J. KRUGER

Abstract

Facial masculinity may be used as a cue in female mate choice, as it reflects the success of the male genotype in its developmental environment. Women may maximize reproductive success by using a conditional strategy favoring highly masculine facial features for short-term relationships and feminized facial features in men for long-term relationships. Three studies examine reactions to masculinized and feminized male facial composites. Properties of the original composite image affect ratings of critical attributes and the magnitude of the differences in ratings between versions undergoing identical processes of geometric manipulation (Study 1). Both men and women attribute personality, behavior, and mating strategies consistent with predictions derived from the good genes and mating trade-off hypotheses (Study 2). Participants accurately grouped behavioral tendencies related to high mating effort/risky strategies and high parenting effort/risk adverse strategies and associated mating effort more so with masculinized faces and parenting effort more so with feminized faces (Study 3). These results indicate that male facial masculinity serves as a visual cue for inferring personality and reproductive strategy.

Link

The Perfect comedy face

Anthony Little has created a facial composite of comedians. From the BBC:

Scientists have used computer software to come up with what they say is the perfect comedy face.

The University of Stirling team blended together 179 different facial aspects of 20 top comedians.

They said soft and feminine features, typified by Ricky Gervais, were more likely to make people laugh.

The researchers also concluded that Conservative leader David Cameron, unlike Tony Blair or Gordon Brown, has features prone to make people laugh.

However, they said it was questionable whether a funny face was an electoral asset.

Researcher Dr Anthony Little, a psychologist, whose work was commissioned by Jongleurs comedy clubs, showed faces with a range of different features to volunteers, and asked them to rate how funny they thought the person was.

He said: "The features most likely to mark male comedians out for success are predominantly soft and feminine.

"The face is a strong indication of character, and today's study appears to explain why comedians of a certain appearance would have been drawn to their career.

"The characteristics of a feminine face imply that the person may be agreeable and co-operative, which can be causal in our first impressions of comedians as being friendly and funny."

Dr Little said Mr Cameron's round and wide facial shape, large eyes and soft features meant he had the right natural physical attributes for comedy.

Femininity/Masculinity predicts male but not female homosexuality

A new article illustrates that masculinity-feminity of adolescents predicts sexual orientation in adulthood for males, but not for females. In other words, effeminate adolescents tend to grow up to be gay but this is not the case for more masculine women.

This illustrates that male and female homosexuality are different phenomena, something which is also apparent by (a) the greater prevalence of male compared to female homosexuality, and (b) the much more obvious behavioral cues of male compared to female homosexuals.

As I wrote in the old Dodona forum in 2004, distinguishing between male and female homosexuality:

Some boys are naturally effeminate or girly and are more prone to develop an abnormal sexuality during their childhood. Homosexuality is a mental illness but one which is difficult to treat because it starts early on and becomes a part of a person's core personality by the time he becomes an adult. While most men learn to act like men as part of the growin up process, homosexuals must unlearn their whole development and relearn a sexual role, something which is virtually impossible.

For lesbians, the cause is probably ugliness or fear of men. While male homosexuals often have a 'normal' appearance, lesbians tend to be unattractive -- except in porn movies of course.

Journal of Biosocial Science (forthcoming)

MASCULINITY–FEMININITY PREDICTS SEXUAL ORIENTATION IN MEN BUT NOT IN WOMEN

J. RICHARD UDRY a1 and KIM CHANTALA

Abstract

Using the nationally representative sample of about 15,000 Add Health respondents in Wave III, the hypothesis is tested that masculinity–femininity in adolescence is correlated with sexual orientation 5 years later and 6 years later: that is, that for adolescent males in 1995 and again in 1996, more feminine males have a higher probability of self-identifying as homosexuals in 2001–02. It is predicted that for adolescent females in 1995 and 1996, more masculine females have a higher probability of self-identifying as homosexuals in 2001–02. Masculinity–femininity is measured by the classical method used by Terman & Miles. For both time periods, the hypothesis was strongly confirmed for males: the more feminine males had several times the probability of being attracted to same-sex partners, several times the probability of having same-sex partners, and several times the probability of self-identifying as homosexuals, compared with more masculine males. For females, no relationship was found at either time period between masculinity and sex of preference. The biological mechanism underlying homosexuality may be different for males and females.

Link

Peter Frost on the evolution of blondness

This is an interesting hypothesis, but one which suffers from a lack of genetic documentation. If indeed there was an imbalance in the operational sex ratio of early northern and eastern Europeans, then one could discover its signal in patterns of diversity of Y-chromosomal and mitochondrial polymorphisms in depigmented vs. non-depigmented Caucasoids.

My own theory explains the evolution of blondness as a paedomorphic trait that was differentially selected in Caucasoid populations due to its interaction with other phenotypic traits.

Briefly, I propose that hair acts as a frame, drawing attention to an individual's features. The prehistoric northern Caucasoids were broad-faced and coarse-featured (Cro-Magnoid) with a robust type of appearance. Dark hair would act to emphasize these robust features in women, while light hair would act to de-emphasize them, giving a more "feminine" appearance.

After Neolithic times, in the south appeared the narrow-faced and gracile types (Mediterranean), who had a more refined appearance, and these types gradually spread, replacing the coarse types. Coarse-featured women needed an extra boost to compete against the more feminine narrow-faced ones, and light hair provided that boost.

Thus in the long-term there was a trend for selection of narrow-faced women over broad-faced ones, but also a trend for selection of blonde women because of the advantage of robust-blondes over robust-brunettes. This explains the joint survival of blondism and robust types (named Brunn, Faelisch, East Baltic, Borreby, etc.) in northern latitudes.

We can definitely observe the first trend in the palaeoanthropological record, as the skeletally Cro-Magnoid population was gradually replaced by Nordoid types in northern Europe. The second trend cannot be directly observed, but the clinal gradation of hair blondism from a peri-Baltic nexus strongly suggests a more recent spread. This may also be sugggested by some ancient DNA analyses and the possibly late Paleolithic origin of an allele for light pigmentation recently discovered.

Evolution and Human Behavior (in press)

European hair and eye color
A case of frequency-dependent sexual selection?

Peter Frost

Abstract

Human hair and eye color is unusually diverse in northern and eastern Europe. The many alleles involved (at least seven for hair color) and their independent origin over a short span of evolutionary time indicate some kind of selection. Sexual selection is particularly indicated because it is known to favor color traits and color polymorphisms. In addition, hair and eye color is most diverse in what used to be, when first peopled by hunter-gatherers, a unique ecozone of low-latitude continental tundra. This type of environment skews the operational sex ratio (OSR) of hunter-gatherers toward a male shortage in two ways: (1) men have to hunt highly mobile and spatially concentrated herbivores over longer distances, with no alternate food sources in case of failure, the result being more deaths among young men; (2) women have fewer opportunities for food gathering and thus require more male provisioning, the result being less polygyny. These two factors combine to leave more women than men unmated at any one time. Such an OSR imbalance would have increased the pressures of sexual selection on early European women, one possible outcome being an unusual complex of color traits: hair- and eye-color diversity and, possibly, extreme skin depigmentation.

Link

Attractiveness and sexual activity

Evolution and Human Behavior Volume 26, Issue 2 , March 2005, Pages 186-201

Attractiveness and sexual behavior: Does attractiveness enhance mating success?

Gillian Rhodes et al.

Abstract

If attractiveness is an important cue for mate choice, as proposed by evolutionary psychologists, then attractive individuals should have greater mating success than their peers. We tested this hypothesis in a large sample of adults. Facial attractiveness correlated with the number of short-term, but not long-term, sexual partners, for males, and with the number of long-term, but not short-term, sexual partners and age of first sex, for females. Body attractiveness also correlated significantly with the number of short-term, but not long-term, sexual partners, for males, and attractive males became sexually active earlier than their peers. Body attractiveness did not correlate with any sexual behavior variable for females. To determine which aspects of attractiveness were important, we examined associations between sexual behaviors and three components of attractiveness: sexual dimorphism, averageness, and symmetry. Sexual dimorphism showed the clearest associations with sexual behaviors. Masculine males (bodies, similar trend for faces) had more short-term sexual partners, and feminine females (faces) had more long-term sexual partners than their peers. Feminine females (faces) also became sexually active earlier than their peers. Average males (faces and bodies) had more short-term sexual partners and more extra-pair copulations (EPC) than their peers. Symmetric women (faces) became sexually active earlier than their peers. Given that male reproductive success depends more on short-term mating opportunities than does female reproductive success, these findings suggest that individuals of high phenotypic quality have higher mating success than their lower quality counterparts.

Link

Beautiful wives and gay sons

Jeet at Gene Expression links to a new study which discovers that female relatives of the mothers of male homosexuals produce more offspring. Thus a particular genetic predisposition manifests itself as homosexuality in a man and as increased fertility in a woman. Homosexuality is due to gene(s) which are (obviously) detrimental to a man's genetic fitness but are advantageous for his female relatives.

This would agree with my recent idea that a person's sexual orientation is a combination of masculinity/femininity genetic factors inherited from his/her parents.

Male homosexuals would thus tend to have more feminine parents. A more feminine mother would give birth to more children, both because she would be more attractive, and thus likely to be married early, but also because femininity is probably a good indication of a woman's reproductive health.

If this intuition is correct, then in layman's terms, if your wife's female relatives have big families, then on the up side there's an increased chance that you have a beautiful and fertile wife, but on the down side there is an increased chance that your son will be gay.

Are women getting more feminine?

A reader of iSteve writes that perhaps women are getting more feminine:

I suspect the traits that make being a mother attractive are "feminine", such as taking pleasure in nurturing others. An ambitious woman with a aggressive personality is likely to choose to be a newspaper reporter (explaining partially why the writers or so feminist), but this choice is likely to go along with having fewer children. (Alas, high IQ makes a interesting career easier to achieve and leads to fewer offspring). Thus, I suspect there is already strong selection for femininity.

An interesting suggestion, but an argument can be made in favor of women becoming less "feminine". If a person's femininity or masculinity depends on how feminine/masculine their parents are, then in today's age many "feminine" men are choosing the homosexual lifestyle [1] instead of choosing to lead a "regular" family life. This probably shifts the genetic balance in favor of "masculine" traits, in addition to the common observation that often girls might pick up more "male-like' traits due to being raised in a house by a "masculine" father who does man-like activities [2]

A second argument is that success in the workplace in many cases depends on being attractive. Attractive, feminine women get more career breaks, hence they may be more likely to have decreased fitness. Not to mention that attractive people are often more intelligent, as both intelligence and attractiveness are partially depended on health which in turn depends on genetic factors.

[1] Lesbians on the other hand are (i) fewer than male homosexuals, and (ii) have a much easier option of having kids if they choose to. Hence increased lesbianism and increased male homosexuality do not balance each other out.
[2] This would affect the frequency of feminine phenotypes but would probably be counterbalanced by improved cosmetic technologies which are leading to a more efficient phenotypic feminization of women.

Havelock Ellis on British brunettes

I had previously written about Havelock Ellis' study at the National Portrait Gallery. Recently, I came across an interesting excerpt by Ellis, which confirms my impression that brunettes are overrepresented in the British aristocracy, and gives an evolutionary explanation for this phenomenon. His explanation ties in quite well with my theory on the evolution of blondness. In summary, my theory holds that:

1. Hair acts like a frame, emphasizing facial features.
   
2. Light hair "softens" features, while dark hair makes them more prominent, just as a frame draws attention to the painting.
   
3. Women with "hard" features have a higher reproductive fitness if they are blond, since they look more feminine, due to the above-mentioned softening effect.
   
4. Hence, there is sexual selection in favor of light hair which however operates primarily on facially robust and un-feminine populations.
   
5. This selection allows the robust and un-feminine characteristics to persist if they are linked with light hair; by contrast, in a brunet population, sexual selection operates on facial characteristics alone, leading to a swifter selection for facial beauty.
   
6. Superior beauty is primarily a function of facial features, and since (i) good facial features are enhanced by framing, and (ii) brunet populations evolve towards a more attractive facial structure faster, it follows that brunettes are on average more attractive than blondes facially.
   

Of course, I personally accept the last point of the above list, but it is possible that I might be biased. I had previously discovered a BBC Story which seemed to confirm my opinion. It was thus pleasantly surprising to see that this preference for dark hair is nothing new, but was noticed almost a century ago, and indeed by Havelock Ellis, whose escapade in the National Portrait Gallery was intended to show the alleged "superiority" of blonds.

I came across this quote in Joana Pitman's rather fluffy book On Blondes, p. 168, citing Ellis in The Monthly Review, August 1901. Ellis' words are in quotes (')

The low position of the hereditary aristocracy [DP: low in "blondness"] was also explained by infusions of foreign blood, and because 'peers have been in a position to select as wives... the most beautiful women, and there can be little doubt that the most beautiful women, at all events in our own country, have tended more to be dark than to be fair. This is proved by the low index of pigmentation of the famous beauties in the Gallery.'

It would certainly be interesting to do an experiment that would confirm this theory. I can think of two possible setups:

1. Artificially change the pigmentation of women photos, and determine whether attractiveness ratings improve when unattractive brunettes are given light hair and deteriorate when unattractive blondes are given dark hair, and that no or the opposite effect occurs from attractive women of either color.
   
2. Compare random samples of blondes from a naturally blond population (e.g., from Sweden) with a random sample of brunettes from a naturally brunet one (e.g., from Spain) after removing the differences in hair color.