Home » Sex Differences
Category Archives: Sex Differences
“Women may be hardwired to prefer pink“, “Study: Why Girls Like Pink“, “Do girls like pink because of their berry-gathering female ancestors?“, “Pink for a girl and blue for a boy – and it’s all down to evolution” are some of the popular news headlines that came out 12 years ago when Hurlbert and Ling (2007) published their study Biological components of sex differences in color preference. They used 208 people, 171 British Caucasians, 79 of whom were male, 37 Han Chinese (19 of whom were male). Hurlbert and Ling (2007) found that “females prefer colors with ‘reddish’ contrast against the background, whereas males prefer the opposite.”
Both males and females have a preference for blueish and reddish hues, and so, women liking pink is an evolved trait, on top of having a preference for blue. The authors “speculate that this sex difference arose from sex-specific functional specializations in the evolutionary division of labour.” So specializing for gathering berries, the “female brain” evolved “trichromatic adaptations”—that is, three colors are seen—which is the cause for women preferring “redder” hues. Since women were gatherers—while men hunters—they needed to be able to discern redder/pinker hues to be able to gather berries. Hurlbert and Ling (2007) also state that there is an alternative explanation which “is the need to discriminate subtle changes in skin color due to emotional states and social-sexual signals ; again, females may have honed these adaptations for their roles as care-givers and ‘empathizers’ .”
The cause for sex differences in color preference are simple: men and women faced different adaptive problems in their evolutionary history—men being the hunters and women the gatherers—and this evolutionary history then shaped color preferences in the modern world. So women’s brains are more specialized for gathering-type tasks, as to be able to identify ripe fruits with a pinker hue, either purple or red. Whereas for males they preferred green or blue—implying that as men evolved, the preference for these colors was due to the colors that men encountered more frequently in their EEA (evolutionary environment of adaptedness).
He et al (2011) studied 436 Chinese college students from a Chinese university. They found that men preferred “blue > green > red > yellow > purple > orange > white > black > pink > gray > brown,” while women preferred “purple > blue > yellow > green > pink > white > red > orange > black > gray > brown” (He et al, 2011: 156). So men preferred blue and green while women preferred pink, purple and white. Here is the just-so story (He et al, 2011: 157-158):
According to the Hunter-Gatherer Theory, as a consequence of an adaptive survival strategy throughout the hunting-gathering environment, men are better at the hunter-related task, they need more patience but show lower anxiety or neuroticism, and, therefore would prefer calm colors such as blue and green; while women are more responsible to the gatherer-related task, sensitive to the food-related colors such as pink and purple, and show more maternal nurturing and peacefulness (e.g., by preferring white).
Just-so stories like this come from the usual suspects (e.g., Buss, 2005; Schmidt, 2005). Regan et al (2001) argue that “primate colour vision has been shaped by the need to find coloured fruits amongst foliage, and the fruits themselves have evolved to be salient to primates and so secure dissemination of their seeds.” Men are more sensitive to blue-green hues in these studies, and, according to Vining (2006), this is why men prefer these colors: it would have been easier for men to hunt if they could discern between blue and green hues; that men like these kinds of colors more than the other “feminine” colors is evidence in favor of the “hunter-gatherer” theory.
(Image from here.)
So, according to evolutionary psychologists, there is an evolutionary reason for these sex differences in color preferences. If men were more likely to like blueish-greenish hues over red ones, then we can say that it was a specific adaptation from the hunting days: men need to be able to ascertain color differences which would have them be better hunters—preferring blue for, among other reasons, the ability to notice sky and water, as they would be better hunters if they did. And so, according to the principle of evolution by natural selection, the men who could ascertain these colors and hues had better reproductive success over those that could not, and so those men passed their genes onto the next generation, which included those color-sensing genes. The same is true for women: that women prefer pinkish, purpleish hues is evidence that, in an evolutionary context, they needed to ascertain pinkish, purpleish colors as to identify ripe fruits. And so again, according to this principle of natural selection, these women who could better ascertain colors and hues more likely to be seen in berries passed their genes on to the next generation, too.
This theory hinges, though, on Man the Hunter and Woman the Gatherer. Men ventured out to hunt—which explains the man’s color preferences—while women stayed at the ‘home’ and took care of the children and looked to gather berries—which explains women color preferences (gathering pink berries, discriminating differences in skin color due to emotional states). So the hypothesis must have a solid evolutionary basis—it makes sense and comports to the data we have, so it must be true, right?
Here’s the thing: boys and girls didn’t always wear blue and pink respectively; this is something that has recently changed. Jasper Pickering, writing for The Business Insider explains this well in an interview with color expert Gavin Moore:
“In the early part of the 20th Century and the late part of the 19th Century, in particular, there were regular comments advising mothers that if you want your boy to grow up masculine, dress him in a masculine colour like pink and if you want your girl to grow up feminine dress her in a feminine colour like blue.”
“This was advice that was very widely dispensed with and there were some reasons for this. Blue in parts of Europe, at least, had long been associated as a feminine colour because of the supposed colour of the Virgin Mary’s outfit.”
“Pink was seen as a kind of boyish version of the masculine colour red. So it gradually started to change however in the mid-20th Century and eventually by about 1950, there was a huge advertising campaign by several advertising agencies pushing pink as an exclusively feminine colour and the change came very quickly at that point.”
While Smithsonian Magazine quotes the Earnshaw Infants Department (from 1918):
The generally accepted rule is pink for the boys, and blue for the girls. The reason is that pink , being a more decided and stronger color, is more suitable for the boy, while blue, which is more delicate and dainty, is prettier for the girl.
So, just like “differences” in “cognitive ability (i.e., how if modern-day “IQ” researchers would have been around in antiquity they would have formulated a completely different theory of intelligence and not used Cold Winters Theory), if these EP-minded researchers had been around in the early 20th century, they’d have seen the opposite of what they see today: boys wearing pink and girls wearing blue. What, then, could account for such observations? I’d guess something like “Boys like pink because it’s a hue of red and boys, evolved as hunters, had to like seeing red as they would be fighting either animals or other men and would be seeing blood a majority of the time.” As for girls liking blue, I’d guess something like “Girls had to be able to ascertain green leaves from the blue sky, and so, they were better able to gather berries while men were out hunting.”
That’s the thing with just-so stories: you can think of an adaptive story for any observation. As Joyner, Boros, and Fink (2018: 524) note for the Bajau diving story and the sweat gland story “since the dawn of the theory of evolution, humans have been incredibly creative in coming up with evolutionary and hence genetic narratives and explanations for just about every human trait that can be measured“, and this can most definitely be said for the sex differences in color preferences story. We humans are very clever at making everything an adaptive story when there isn’t one to be found. Even if it can be established that there are such things as “trichomatic adaptations” that evolved for men and women liking the colors they do, then, the combination of functional effect (women liking pink for better gathering and men liking blue and green for better hunting) and that the trait truly was “selected-for” does not license the claim that selection acted on the specific trait in question since we cannot “exclude the possibility that selection acted on some other pleiotropic effect of the mutation” (Nielsen, 2009).
In sum, the causes for sex differences in color preferences, today, makes no sense. These researchers are just looking for justification for current cultural/societal trends in which sex likes which colors and then weaving “intricate” adaptive stories in order to claim that part of this is due to men’s and women’s “different” evolutionary history—man as hunter and woman as gatherer. However, due to how quickly things change in culture and society, we can be asking questions we would not have asked before due to how quickly society changes, and then ascribe evolutionary causes for out observations. As Constance Hilliard (2012: 85) writes, referring to Professor Michael Billig’s article A dead idea that will not lie down (in reference to race science), “… scientific ideas did not develop in a vacuum but rather reflected underlying political and economic trends.“
Skin color differences between the sexes are always discussed in terms of women being lighter than men, but never men being darker than women. This is seen in numerous animal studies (some reviewed by Rushton and Templer, 2012; read rebuttal here; also see Ducrest, Keller, and Roulin, 2008). Though, the colors that evolved on the animal’s fur due to whatever mate choices are irrelevant to the survival capabilities that the fur, feathers etc give to the organism in question. So, when we look at humans, we lost our protective body hair millions of years ago (Lieberman, 2015), and with that, we could then sweat. So since furlessness evolved in the lineage Homo, there was little flexibility in what could occur due to environmental pressures on skin color in Africa. It should be further noted that, as Nina Jablonski writes in her book Living Color: The Biological and Social Meaning of Skin Color (2012, pg 74)
No researchers, by the way, have explored the opposite possibility, that women deliberately selected darker men!
One hypothesis proposes that lighter skin in women first arose as a byproduct due to the actions of differing levels of hormones in the sexes—with men obviously having higher levels of testosterone, making them darker them women. So according to this hypothesis, light-skinned women evolved since men could tell high-quality from low-quality mates as well as measure hormonal status and childbearing potential, which was much easier to do with lighter- than darker-skinned women.
Another hypothesis put forth is that further from the equator, sexual competition between women would have increased for mates since mates were depleted, and so light skin evolved since men found it more beautiful. Thus, women living at higher latitudes were lighter than women living at lower latitudes because men had to go further to hunt which meant they were more likely to die which caused even greater competition between females, lightening their skin even more. And another, related, argument, proposed that light skin in women evolved due to a complex of childlike traits which includes a higher voice, smoother skin and childlike facial features, which then reduced male competition and aggressiveness. But women did not stay around waiting to be provisioned and they got out and gathered, and hunted sometimes, too.
Harris (2005) proposes that light skin evolved due to parental selection—mothers choosing the lightest daughters to survive, killing off the darker ones. All babies are born pale—or at least lacking the amount of pigment they have later in life. So how would parental—mostly maternal—selection have caused selection for lighter skin in girls as Harris (2005) proposes? It’d be a pretty large guessing game.
The role of sexual selection in regard to human skin color, though, has been tested and falsified. Madrigal and Kelly (2007a) tested the hypothesis that skin reflectance should be positively correlated with distance from the equator. It was proposed by other authors that as our ancestors migrated out of Africa, environmental selection relaxed and sexual selection took over. Their data did not lend credence to the hypothesis and falsified it.
Madrigal and Kelly (2007a: 475) write (emphasis mine):
We tested the hypothesis that human sexual dimorphism in skin color should be positively correlated with distance from the equator, a proposal generated by the sexual selection hypothesis. We found no support for that proposition. Before this paper was written, the sexual selection hypothesis was based on stated male preference data in a number of human groups. Here, we focused on the actual pattern of sexual dimorphism. We report that the distribution of human sexual dimorphism in relation to latitude is not that which is predicted by the sexual selection hypothesis. According to that hypothesis, in areas of low solar radiation, there should be greater sexual dimorphism, because sexual selection for lighter females is not counterbalanced by natural selection for dark skin. Our data analysis does not support this prediction.
Though Frost (2007) replied, stating that Madrigal and Kelly (2007a) presumed that sexual selection was equal in all areas. Madrigal and Kelly (2007b) responded, stating that they tested one specific hypothesis regarding sexual selection and found it to be false. Frost (2007) proposed two hypotheses in order to test his version, but, again, no one has proposed that women select darker men, which could be a cause of lighter-skinned women (though sexual selection does not—and cannot—explain the observed gradation in skin color between men and women).
Skin color differences between men and women first arose to ensure women enough calcium for lactation and pregnancies. Since skin pigmentation protects against UVR but also must generate vitamin D, it must be light or dark enough to ensure ample vitamin D production in that certain climate, along with protecting against the UVR in that climate. So women needed sufficient vitamin D, which meant they needed sufficient calcium to ensure a strong skeleton for the fetus, for breastfeeding and for the mother’s own overall health.
However, breastfeeding new babes is demanding on the mother’s body (calcium reserves are depleted four times quicker), and the calcium the babe needs to grow its skeleton comes directly from the mother’s bones. Even a mother deficient in vitamin D will still give calcium to the babe at the expense of her own health. But she then needs to increase her reserves of calcium in order to ensure future pregnancies aren’t fatal for her or her offspring.
Though, at the moment to the best of my knowledge, there are no studies on calcium absorption, vitamin D levels and the recovery of the female skeleton after breastfeeding. (Though n3 fatty acids are paramount as well, and so a mother must have sufficient fat stores; see Lassek and Gaulin, 2008.) Thus, light-skinned women are most likely at an advantage when it comes to vitamin D production: The lighter they are, the more vitamin D and calcium they can produce for more pregnancies. Since light skin synthesizes vitamin D more efficiently, the body could then synthesize and use calcium more efficiently. The body cannot use and absorb calcium unless vitamin D is present. Since the fetus takes calcium from the mother’s skeleton, ample amounts of vitamin D must be present. For ample amounts of vitamin D to be present, the skin must be light enough to ensure vitamin D synthesis which would be needed for calcium absorption (Cashman, 2007; Gallagher, Yalamanchili, and Smith, 2012; Aloia et al, 2013).
Nina Jablonski writes in her book (2012, 77):
Women who are chronically deficient in vitamin D because of successive pregnancies and periods of breastfeeding experience a form of bone degeneration called osteomalacia. This has serious consequences for infants born of later pregnancies and for mothers themselves, who are at greater risk of breaking bones. It makes sense that protection of female health during the reproductive years would be a top evolutionary priority, so we are now investigating whether, in fact, slightly lighter skin in women might be a fairly simple way of ensuring that women get enough vitamin D after pregnancy and breastfeeding to enable their bodies to recover quickly. The need for maintaining strong female skeletons through multiple pregnancies may have been the ultimate evolutionary reason for the origin of differences in skin color between men and women.
While Jablonski and Chaplin (2000: 78) write:
We suggest that lighter pigmentation in human females began as a trait directly tied to increased fitness and was subsequently reinforced and enhanced in many human populations by sexual selection.
It is obvious that skin color in women represents a complex balancing act between giving the body the ability to synthesize ample vitamin D and protect from UVR. Skin coloration in humans is very clearly highly adaptive to UVR, and so, with differing average levels of UVR in certain geographic locales, skin color would have evolved to accommodate the human body to whichever climate it found itself in—because human physiology is perhaps the ultimate adaptation.
Sexual selection for skin color played a secondary, not primary role (Jablonski, 2004: 609) in the evolution of skin color differences between men and women. There is a delicate balancing act between skin color, vitamin D synthesis, and UVR protection. Women need to produce enough vitamin D in order to ensure enough calcium and its absorption to the baby and then ensure there are ample amounts to replace what the baby took while in the womb in order for future pregnancies to be successful. Sexual selection cannot explain the observed gradation in skin color between the races and ethnies of the human race. In my opinion, the only explanation for the observed explanation is the fact that skin color evolved due to climatic demands, while independent justification exists for the hypothesis as a whole (Jablonski and Chaplin, 2010).
I don’t see any way that sexual selection can explain the observed gradation in skin color around the world. Skin color is very clearly an adaptation to climate, though of course, cultural customs could widen the skin color differences between the sexes, and make women lighter over time. Nevertheless, what explains the observed skin gradation is adaptation to climate to ensure vitamin D synthesis among a slew of other factors (Jones et al, 2018). Sexual selection, while it may explain small differences between the sexes, cannot explain the differences noted between the native human races.
By Scott Jameson
Long and short of this issue is that something has to explain why most of the really, really smart people are men. There are two hypotheses: men have a higher mean, and men have a higher standard deviation. They don’t really have to compete, and so some people believe that both are true. Some believe neither, of course.
Let’s start with three facts:
- Women tend to get slammed by men on Raven’s Progressive Matrices; the second graph in the post linked above details this. It’s a difference of 5 IQ points on average, quite a bit, certainly more than on other IQ tests.
- Women tend to lose even harder in visuospatial measures. John Loehlin pointed out in The Handbook of Intelligence that the gap here was a whopping 13.5 points.
- Raven’s is so g loaded because your score is primarily driven by spatial and verbal-analytic abilities.
The biggest subtest difference is spatial, and I think that likely explains the abnormally large differences in Raven’s scores. Other IQ tests, like the SAT, hardly use visual abilities. Women do about as well as men on the SAT. I’ve also seen the White-Asian gap smaller on the SAT than in other IQ tests, and that gap is also driven in large part by spatial scores. Conversely you might expect the SAT to go better for a hypothetical demographic that scores well in math and verbal abilities, but not especially well in spatial. By hypothetically I mean that these people make up like a fifth of the kids at the Ivy Leagues, even more than you’d expect from an average IQ of, I don’t know, 111ish.
Off topic: these differences are probably going to be slighter still now that they’re fastidiously removing every useful element of the test in an effort to make it less “biased” by race. I wonder if colleges will just throw up their shoulders and start looking for kids who do well on the ACT. Moving on.
There are other sex differences in subtest scores. Pulling from Loehlin again: “females tend to have an advantage on verbal tests involving the fluent production of words belonging to a category, such as synonyms.” Women are known to do better on verbal than on math.
Loehlin also points out that girls do better at math in early childhood, but that boys outstrip them by the time it, uh, matters, when they take standardized tests in adolescence.
I have a wild hypothesis that men and women respectively being more oriented towards mathematical and verbal thought corresponds to observed differences in interests. Women are known to read more often than men on average, whereas male dominated activities like sports and video games often have a distinctly mathematical bent. My spurious hypothesis is that doing these different things differentially develops their abilities, constituting an example of crystallized intelligence rather than fluid intelligence; alternatively, they were differentially selected for ability to perform well on tasks that their respective sex does more of, in which case the abilities are innate.
Even if they aren’t innate, it’d be an instance of secondary heritability because evidence tends to show male-female personality differences as innate; in this scenario they are innately prone to practicing different abilities to different extents.
Loehlin points to Hedges and Nowell’s 1995 meta-analysis, showing a higher male variation in IQ and elucidating a few more small subtest differences. I’ve lifted a meaty bit here:
On average, females exhibited a slight tendency to perform better on tests of reading comprehension, perceptual speed, and associative memory, and males exhibited a
slight tendency to perform better on tests of mathematics and social studies. All of the effect sizes were relatively small except for those associated with vocational aptitude scales (mechanical reasoning, electronics information, and auto and shop information) in which average males performed much better than average females. The effect sizes for science were slightly to moderately positive, and those for perceptual speed were slightly to moderately negative. Thus, with respect to the effect size convention, these data suggest that average sex differences are generally rather small.
- There are sex differences in scores of various IQ subtests, including but not limited to female orientation towards verbal and male orientation towards mathematical ability.
- The largest of these differences is a substantial male advantage in spatial ability.
- On any IQ test that doesn’t weight subtests such that men and women perform equally by default, men tend to score a hair better.
- Men also have a higher standard deviation in IQ.
There are more male geniuses, particularly with respect to mathematical genius. There are also more mentally retarded males. I just explained why men tend to populate CERN, NASA, Silicon Valley, and lists of who’s died in the Running of the Bulls.
Testosterone gets a bad rep. People assume that if one has higher testosterone than average, that they will be a savage, bloodthirsty beast with an insatiable thirst for blood. This, however, is not the case. I’ve documented how testosterone is vital for male functioning, and how higher levels don’t lead to maladies such as prostate cancer. Testosterone is feared for no reason at all. The reason that people are scared of it is that of the anecdotal reports that individual A had higher testosterone when he committed crime B so, therefore, anyone who commits a crime has higher testosterone and that is the ultimate—not proximate—cause of crime. This is erroneous. There is a positive—albeit extremely low—correlation between physical aggression and violence at .14. That’s it. Furthermore, most of these claims of higher levels of testosterone causing violence is extrapolated from animal studies to humans.
Testosterone has been shown to lead to violent and aggressive behavior, largely only in animal studies (Archer, 1991; Book et al, 2001). For years, the relationship between the two variables was thought to be causal, i.e., high levels of testosterone cause violent crimes, which has been called into question over recent years. This is due to how the environment can raise testosterone levels. I have documented how these environmental factors can raise testosterone—and after these events, testosterone stays elevated.
Largely, animal studies are used to infer that high levels of testosterone in and of themselves lead to higher rates of aggression and therefore crime. However, two important meta-analyses show this is not necessarily the case (Archer, 1991; Book et al, 2001). Book et al, 2001 showed that two variables were important in seeing the relationship between aggression and crime—the time of day that the assay was taken and the age of the participant. This effect was seen to be largest in, not unexpectedly, males aged 13-20 (Book et al, 2001: 594). So since age confounds the relationship between aggression and testosterone in males, that is a variable that must also be controlled for (which, in the meta-analyses and other papers I cite on black and white testosterone is controlled for).
More interestingly, Book et al (2001) showed that the nature of the measure of aggression (self-reported or behavioral) did not have any effect on the relationship between testosterone and aggression. Since there is no difference between the two measures, then a pencil-and-paper test is a good enough index of measure of aggression, comparable to observing the behavior of the individual studied.
Archer (1991) also showed the same low—but positive—correlations between aggression and testosterone. Of course, as I’ve extensively documented since there is a positive relationship between the two variables does not necessarily mean that high-testosterone men commit more crime—since the outcome of certain situations can increase and decrease testosterone, no causal factors have been detangled. Book et al (2001) confirmed Archer’s (1991) finding that the correlation between violent and aggressive behavior was positive and low at .14.
Valois et al (2017) showed there was a relationship between emotional self-efficacy (ESE) and aggressive and violent behaviors in a statewide sample of high school children in South Carolina (n=3,386). Their results suggested that there was a relationship between carrying a weapon to school within the past 30 days along with being injured with a club, knife or gun in the past 12 months was significantly associated with ESE for specific race and sex groups.
Black girls who reported a low ESE reported carrying a weapon to school 30 days prior to the survey were 3.22 times more than black girls with a high ESE who did not report carrying a weapon to school within the past 30 days prior to the questionnaire. For black boys with low ESE, they were 3.07 times more likely to carry a weapon to school within the past 30 days in comparison to black boys with high ESE who did not carry a weapon to school in the past 30 days. White girls who reported low ESE had the highest chance of bringing a weapon to school in comparison to white girls with low ESE—they were 5.87 times more likely to carry a weapon to school 30 days prior to the survey. Finally, white boys with low ESE were slightly more than 2 times more likely than white boys with high ESE to carry a weapon to school 30 days prior to the survey.
Low ESE in white and black girls is associated with carrying a weapon to school, whereas low ESE for white and black boys is associated with being threatened. Further, their results suggested that carrying a weapon to school was associated with low ESE in black and white girls suggesting that low ESE is both situation-specific and specific to the female sex. The mediator between these things is low ESE—it is different for both black boys and black girls, and when it occurs different courses of action are taken, whether it’s through bringing a weapon to school or being threatened. What this tells me is that black and white boys with low ESE are more likely to be threatened because they are perceived to be more meek, while black and white girls with low ESE that get provoked at school are more likely to bring weapons. So it seems that girls bring weapons when provoked and boys fight.
The two meta-analyses reviewed above show that there is a low positive (.14) correlation between testosterone and aggression (Archer, 1991; Book et al, 2001). Thusly, high levels of testosterone on their own are not sufficient enough to explain high levels of aggression/violence. Further, there are race- and sex-specific differences when one is threatened at high school with black and white boys being more likely to report being threatened more (which implies a higher rate of physical fighting) while black and white girls when threatened brought weapons to school. These race- and sex-specific differences in the course of action taken when they are physically threatened needs to be looked into more.
I’d like to see the difference in testosterone levels for a matched sample of black and white boys from two neighboring districts with different murder rates as a proxy for the amount of violence in the area. I’d bet that the places with a higher murder rate would have children 1) report more violence and instances of bringing weapons to school and 2) report more harm from these encounters—especially if they have low ESE as seen in Valois (2017) and 3) the children in the high schools along with the residents of the area would have higher testosterone than the place with less violence. I would expect these differences to be magnified in the direction of Valois (2017) in that areas with higher murder rates would have black and white girls report bringing weapons to school when threatened whereas black and white boys would report more physical violence.
High testosterone itself is not sufficient enough to explain violence as the correlation is extremely low at .14. Testosterone levels fluctuate depending on the time of day (Brambilla et al, 2009; Long, Nguyen, and Stevermer, 2015) to the time of year (Stanton, Mullette-Gillman, and Huettel, 2011; Demur, Uslu, and Arslun, 2016). How the genders/races react differently when threatened in adolescence is interesting and deserves further study.
Black American men are the least likely male ethnic group to be overweight or obese in America (69.2 percent) compared to ‘Hispanic’ men (78.6 percent) and white men (71.4 percent) (Ogden et al, 2014). As a result of being less likely to be obese, black men as a whole suffer from diabetes and other diseases that are correlated with higher body fat. Conversely, for women the rate for white women is 63.2 percent, 77.2 percent for ‘Hispanic’ women and 82.4 percent for black women. Why do black men have lower rates of obesity and chronic health diseases?
Klimentidis et al (2016) set out to find why black men have lower rates of obesity than black women despite having the same socioeconomic and environmental factors. Using 2814 self-identified African Americans from the Atherosclerosis Risk in Communities study, they estimated each individual’s degree of African ancestry using 3,314 genetic markers. They then tested whether sex modifies the association of West African genetic ancestry and body mass index, waist circumference, and waist to hip ratio. Also, they adjusted for income and education as well as examined associations of ancestry with the phenotypes of males and females separately. They recreated their results with the Multi-Ethnic Study of Atherosclerosis (n= 1611 AA).
They discovered that West African ancestry is negatively correlated with obesity as well as central obesity, which is obesity around the midsection, among black men but not black women. Also noted, was that black men with more African ancestry had a lower waist to hip ratio and less central adiposity than black men with less African ancestry. They conclude that their results suggest that a combination of male gender and West African ancestry is correlated with protection against central obesity and suggests that a portion of the difference in obesity (13.2 percent difference) may be due, in part to genetic factors. The study also suggests that there are specific genetic and physiologic differences in African and European Americans.
This study confirms two things. 1) Black women are more likely to be obese than black men as well as the general population. 2) Black men have less of a chance of becoming obese or overweight as well as less of a chance of incurring the risks that come along with being obese or overweight. The degree of African ancestry is the cause in both black men and black women for these differences in the rate of overweight and obese individuals in both populations. One of my theories also got confirmed. Since obesity is partly genetic in African Americans, and black girls have an earlier menarche (period) than white girls due to higher body fat which activates the hormone leptin, which precedes an increase in body fat to prepare for eventual menstruation, I theorize that black girls have earlier menarche than white girls due to r/K Selection Theory. It’s an evolutionary advantage to be able to have children earlier, as the population dies younger.
Evolutionarily speaking, black men needed to be more fit in order to protect the clan from predators. This is also why blacks evolved narrower hips (Rushton, 1995). Higher body fat allows for more protection for a baby in vitro, which is why an increase in leptin precedes an increase in body fat, which then causes black girls to have an earlier puberty.
One of the questions I would like answered is whether it’s the actual degree of African ancestry that is the cause of black men being less likely to be obese or it’s the cause of higher degree of European ancestry. European American men do have a slightly higher risk of being overweight or obese than African American men, so there is some credence to this hypothesis. Three SNPs were found to be correlated with obesity in African American populations as well as European American populations; this could be one cause.
Wagner and Heyward (2000) discovered biological differences exist between blacks and whites. They reviewed the literature on the differences between blacks and whites in fat-free body mass (water, mineral, and protein) fat patterning and body dimensions and proportions. Blacks, in general, have greater bone mineral density and body protein content than do whites, resulting in lower fat-free bone density. They also note racial differences in the differences of subcutaneous body fat, which is the body fat that’s just below the skin, as opposed to visceral body fat which is found in the peritoneal cavity, which can be measured with calipers to give a rough estimate of total body fat adiposity. The conclusion reached in the study was that differences in FFB (fat-free body) was statistically significant between blacks and whites. They also have a greater BMC (bone mineral content) and BMD (bone mineral density) than do whites. They also argue that for a given BMI (body mass index), blacks might have less adiposity because they tend to be more mesomorphic. Researchers push for the development of racial-specific equations to better see differences in FFB.
With the above study noting that there is a substantial difference between blacks and whites in FFB, there may be some truth to a negative effect of European ancestry on blacks in terms of obesity acquisition. However, lower FFB in black men is one reason why black men can’t swim as well as whites.
One of the causes for both racial and gender discrepancies in obesity is genetic in origin. The difference between black men and black women is 13.2 percent whereas for white men and white women the difference is 8.2 percent. There is a clear genetic difference between races that is the cause for this discrepancy. Black men and black women have the same socioeconomics status and live in the same environment, so some of the differences in obesity noticed in this population must be genetic in origin.
Freedman et al (2004) observed that, as expected, black men were more likely to choose heavier figures as an ideal body for women than white men. Also expected was that both groups would choose figures with a low waist to hip ratio, but black men would choose a lower waist to hip ratio as ideal. They also show weight to be a more important cue than waist to hip ratio in mate selection as well as supporting the theory that black men’s preferences may serve as a protective factor against eating and body image pathology in black women.
To give an example of the above study in action, we can look at Mauritania. They force feed their women up to 16,000 kcal a day in an effort to make them obese, as that’s what is seen as attractive in their society. Mauritanian love songs also describe the ideal woman as fat. Obesity is so celebrated in their society that parents beam at the fact that their daughters look obese, as they have a better chance of getting partners.
The higher the degree of West African ancestry in black men, the lower the chance they have for obesity. I do wonder, though, if it’s because they have less European ancestry or because they have more African ancestry. Black men with more African ancestry are less likely to be obese than black men with less African ancestry, so there is a correlation there that I would like to see explored in the future. Differences in fat-free body mass have been noticed between blacks and whites, but this is one of the first studies to my knowledge that shows that genetic differences between black men and black women may be part of the cause for obesity differences in that population. Cultural differences in perception of beauty, of course, come into play in regards to differences between black and white men, however, the cause of black women having higher rates of obesity is due in part to genetic factors, which then leads to black men liking that as their beauty standard.
The Chinese have one of the highest IQs in the world. Their 100 and 108 in Hong Kong give them an average of 104. Chinese intelligence has been increasing from the 1940s all the way to today. This is the ‘Flynn Effect’ in action. Lui and Lynn (2013) reported that IQ scores are improving for 12-year-old Chinese children. The increases are as follows: 6.19 points for full-scale IQ, 6.55 points for performance IQ, and 1.91 points for verbal IQ. The Jintan Child Study is an ongoing longitudinal study to show the effects of health and cognitive ability.
They used 1656 6th graders (55.5 percent boys and 45.5 percent girls, “consisting of 24.3% of all children in this age range in the Jintan city region born in 1999.”) who either graduated or currently were in the grade with an average age of 12.2 years. The study from 86-87 used only individuals from urban areas, so Liu and Lynn did the same. They conclude that over the 26 years from the original study, between the two data sets that increases of 2.38 points on full-scale IQ, .73 points on verbal, and 2.52 points on performance IQ per decade. They theorize that economic development is a cause of rising IQ scores due to better nutrition. The study concludes a 105.89 IQ for the 12-year-olds in the study.
Liu and Lynn (2015) also observed the same sex differences in the same magnitude in Chinese and American boys and girls. In a study of 788 children aged 12 years old, boys obtained a higher IQ by 3.75 points on average. This exactly mirrors what Rushton and Jackson (2005) say about American men and women who are college aged. They state that males score 3.63 points higher than women. Liu and Lynn state that boys obtained 4.20 points higher in performance IQ, and 2.40 points higher in verbal IQ. This is what we would expect, evolutionarily speaking. The men need to be more intelligent to provide food, whereas women need to have a higher verbal IQ to be able to talk to and take care of children. The fact that the magnitude of sex differences in IQ between men and women has been noticed in the U.S. and China shows that sex differences in the brain do exist.
Better nutrition is a definite cause for the rise in IQ for the Chinese. Richard Lynn says that better nutrition is critical for increased cognitive functioning. This is one reason why Africa’s IQ is so low. Due to more Chinese getting better jobs and making more money, they were getting higher quality foods in order to be adequately nourished. Better nutrition explains most, if not all of the Flynn Effect. It’s what to expect if this phenomenon was not on g (it’s not), it’s on the intelligence that is affected by the environment, hence, bigger increases on that type of intelligence in comparison to the intelligence highly correlated with g.
The Chinese have the largest cranial capacity at 1492 ml. The bigger one’s brain, the more cortical neurons it has which allows for better cognitive processing. Piantadosi and Kidd (2016) corroborated one of Rushton’s theories on brain size and child rearing. Mainly that r/K selection theory explains Piantadosi and Kidd’s theory of earlier births being correlated with higher intelligence due to greater necessity to care for the more vulnerable child in comparison to those with smaller brains. Moreover, since East Asians have more myelin in the brain, this too adds to their higher cognition. Since the correlation between brain size and IQ is .35, a good amount of the variance in IQ can be explained by brain size.
We can also look at Chinese outside of China. Singapore, for instance, has an IQ of 108, the highest in the world. They’re also 74.4 percent Chinese. This is then mirrored in their IQ as well as their economy. Anywhere the Chinese go they are high achievers in both IQ as well as wealth attainment.
There are other measures to show that Chinese have higher IQs. In tests of reaction times, Rushton and Jensen (2005) say that East Asians beat whites while whites beat blacks. Since faster reaction times are associated with a more efficient brain, East Asians have a higher IQ as a result of that. Though, they are weak on verbal IQ, average 99 for Chinese in America and China, they are superior in visio-spatial IQ. This is due to their ancestors evolving in the harsh winters of Siberia which lead to being more K-selected and selecting for bigger brains which lead to children being born earlier and higher intelligence evolving to better care for defenseless children. Bigger brains also evolved due to colder temperatures, which is another cause for earlier childbirth and an even bigger increase in general intelligence to adapt.
IQ in China is higher in urban areas than in rural areas, which is seen in America as well. This is due to those with higher intelligence having the ability to be able to live in the city due to a better ability to attain wealth due to higher IQ. Those in rural areas have lower IQ, some having a lower IQ genetically, while others are depressed by bad nutrition. So with better nutrition, a lot of the rural Chinese would get an IQ boost. Nutrition is critical for brain development in vitro as well as in early childhood leading into young adulthood. This ensures the brain has adequate nutrients for growth and in turn grows to its full potential.
The Chinese are the best example of Rushton’s theory of intelligence and brain size. No matter where they go, if they have adequate nutrition, they have the biggest brains and highest IQs which shows in scholastic achievement as well as wealth attainment. The increase in full-scale IQ for China in the past 30 years is due to better nutrition as well as economic growth. Singapore has one of the world’s best economies and is 74.4 percent Chinese.
This extreme K-selection, though, is causing the Chinese birth rate to drop. This is the curse for high IQ peoples. They have a lower birth rate in comparison to those with lower IQs who have a higher birth rate. The current birth rate in China is 1.66. That is devastatingly low, almost as low as Germany and Japan (both at 1.3) and they have similar IQs as well. It seems that this intelligence increase is coming with a lower birth rate. Higher intelligence is correlated with a lower sex drive so this is another cause for the lower birth rate in East Asian countries as these slight IQ increases continue to occur. The same sex differences as seen in America were also seen in China, giving more evidence to the sexual selection theory of intelligence.
Your success at speed-dating might be influenced by your genetic make-up and your potential partner’s ability to detect so-called ‘good genes.’ The research team found that participants who were more likely to be asked on a second date had genotypes consistent with personal traits that people often desire in a romantic partner.
Coming off of a successful refutation of JayMan (check comments too), more evidence for our claim came out the other day. Us humans can match on genotype, which we, of course, match with people with other similar heritable characteristics. Since humans match on these traits that are more heritable than the ones that are more influenced by environment, then we can say that we are seeking out partners who are like us, therefore matching on genetic similarity.
Wu, et al (2016) examined 262 Asian Americans in a speed-dating setting. The researchers predicted that there would be considerable matching by genotype between the genders. They found that the gene A118G, which is linked to submissiveness and social sensitivity, whereas for the men, the minor variant with the -1438 A/G allele, which is linked to social dominance and leadership, were shown to have greater success. They also discovered that men and women with genotypes consistent with “prevailing gender norms were more likely to receive second date offers”
The researchers say that “These results suggest that personal attributes corresponding to A118G and −1438 A/G can be detected in brief social interactions, and that having a specific genetic variant or not plays a tangible role in dating success,” Those with the A118G polymorphism had greater capacity for experiencing social pleasure and pain as well as their need to have social contact. This also shows how Men and women with the opposite of each allele (men having the A118G allele and women having the -1438 A/G allele) were seen as less desirable mates, showing good evidence that each allele is gender-specific. Wu also believes this effect could also expand to other social interactions, such as job interviews.
This study shows more evidence for Rushton’s theory of spouses matching phenotypically by genotype. Spouses are as similar as 4th cousins. Spousal genetic similarity is a significant driving force for human civilization, as it selected for certain traits over others that then lead to things such as higher IQ in Eurasian men to beauty in Eurasian women, vice versa for Africans. In Eurasian societies, men hunted and while women took care of the children. Higher intelligence then evolved in men due to needing to strategize, among other things such as surviving the frigid temperatures. Women took care of the children, and thus developed a higher verbal IQ as a result of this. In Africa, women gathered food, selecting them for slightly higher intelligence than their male counterparts. Conversely, the African males were selected for attractiveness (Fuerle, 2008).
Those K-selected have lower birth rates, and thus, must be more rigorous in choosing a mate. Choosing a mate based on intelligence showed that the male could provide food as well as protect the family against predators and other bands of humans. R selected humans have more children and show less care, so they have higher birth rates to counter this. They are less rigorous in mate selection due to need to have more children due to a higher death rate. This is mirrored still, even today in modern society. Human sexual selection is one of the reasons why human evolution progressed to the point is has, with the driver being evolution in harsher climates. Eurasian women needed to be more stringent in choosing mates due to a higher chance of death in choosing the wrong mate. Over time, this lead to a ‘genotype sensor’ if you will, which by matching by certain phenotypic traits (facial symmetry, skin color, height, health, etc), chances for intelligent children, better care and more food will come as a result of this stringent selection by women, which in turn lead to evolution of certain traits in Eurasian men and women.
This shows that these human differences in how we select our spouses to how our civilizations ultimately end up is due to a) climate, b) sexual selection and c) genetics. Passing on the best genes lead to an ultimately better society, and as a result, this lead to those genes that were more successful having a chance to produce more copies of themselves, assuring that society would be run well in the future. This is also why government systems such as monarchies have hereditary rulers.
I have said numerous times that the tendency to favor co-ethnics is the tendency to favor shared genes. Benefiting those similar to yourself ensures that you’re benefiting copies of your genes, ensuring your genetic legacy for the future. Matching with those who appear similar to us by genotype when there is such phenotypic similarity shows that this is a trait we humans have to seek out those co-ethnics genetically similar to ourselves.
Towards the end of last year, it was said that “male and female brains don’t differ“. Male and female brains differ from the number of neurons to differences in g that affect intelligence, to differences in temperament and differences in the hormones testosterone and estrogen. Other than accounting for differences in physical appearance between the sexes, the differences between the sexes in the two hormones accounts for brain differences as well. This is yet another blank slate argument, years after cognitive neuroscience affirmed that behavior is rooted in the brain and that we are not in fact “blank slates”, these same old and outdated arguments keep being pushed, of course, in part due to the growing number of “transgenders” and an influx of non-western people who are abnormal to our societies. This attempt to have the general public to believe that we have minds of Silly Puddy (to borrow a phrase from Steven Pinker) is an attempt to have us accept all of the things that get pushed on us through the media.
You may have read that having a male brain will earn you more money.
Men do make more money than women, and this isn’t the cause of the imaginary gender pay gap. Even Thomas Sowell, the liberal icon has refuted this myth. Men make more money than women due to, which I will get to below, higher intelligence.
Or maybe that female brains are better at multitasking.
Anecdotal evidence suggests it. Evolutionary evidence suggests it. Studies suggest it. But ever since the Jewish feminist push in the 20th century, this strive for egalitarianism between the sexes became mainstream, which helps to still keep the notion of “blank slatism” alive.
The idea that people have either a “female” or “male” brain is an old one, says Daphna Joel at Tel Aviv University in Israel. “The theory goes that once a fetus develops testicles, they secrete testosterone which masculinises the brain,” she says. “If that were true, there would be two types of brain.”
Anyone else surprised that someone from Tel Aviv University is making these claims? Are we supposed to believe that testosterone doesn’t affect the brain? Are we supposed to believe that higher testosterone, higher estrogen and other biologic differences in brain structure don’t account for behavioral differences between the sexes?
We have data that this is the case, though:
Sex steroid hormones exert a profound influence on the sexual differentiation and function of the neural circuits that mediate dimorphic behaviors. Both estrogen and testosterone are essential for male typical behaviors in many species. Recent studies with genetically modified mice provide important new insights into the logic whereby these two hormones coordinate the display of sexually dimorphic behaviors: estrogen sets up the masculine repertoire of sexual and territorial behaviors, and testosterone controls the extent of these male displays.
To believe that testosterone doesn’t cause masculinization of the brain will have to have one deny all of the literature out there. Why people believe that sex differences, as well as racial/ethnic differences, are rooted in experience and not biology is truly mind boggling.
“There are not two types of brain”
And below this, they basically say that the “gender fluid” phenomenon is ‘ok’. Differences between individual boys and girls and individual men and women are extremely evident just by casual observation, so to attempt to say that individual brains cannot be shown to have full-on male or female characteristics is insincere. The fact that, as shown above, testosterone mediates the masculinization of the brain, we can see that these differences in brain structure do exist, and are accounted for by exposure to testosterone invitro, which then cause the differences in the brains of men and women.
Although the team only looked at brain structure, and not function, their findings suggest that we all lie along a continuum of what are traditionally viewed as male and female characteristics. “The study is very helpful in providing biological support for something that we’ve known for some time – that gender isn’t binary,” says Meg John Barker, a psychologist at the Open University in Milton Keynes, UK.
Gender is binary. Female and male characteristics do exist. Males and females differ in certain structures of the brain as seen in a study reviewing over 20 years of the study of sex differences in the brain.
“Across all kinds of spatial skills, we find very, very few that are sensitive to sex,” says Hausmann. “We have also identified spatial problems where women outperform men – the black-and-white idea of a male or female brain is clearly too simple.”
The sex differences on spatial skills tests are rooted in brain structure. Researchers measured a 10 percent difference between men and women in overall amount of parietal lobe surface area. Since how we process information is obviously a result of cognitive processes in the mind, differences between the sexes in brain structure show how men and women can differ in certain cognitive tasks. Of course, some spatial problems can be women can outperform men on some spatial tasks, no one disputes that. However, what the average battery of tests shows is that men have higher visio-spatial intelligence than men.
Alexandra Kautzky-Willer, head of the Gender Medicine Unit at the Medical University of Vienna in Austria, agrees that things aren’t so simple. “There are differences between men and women when you look in large groups, and these are important for diagnosis and treatment,” she says. “But there are always more differences within genders. We always need to look at culture, environment, education and a person’s role in society,” she says.
Just like there “is more difference within race than between them”, right? Culture is a product of genetics and IQ, we put ourselves into certain environments based on our genes, education is largely heritable, a person’s worth to society is based on IQ and the Big Five personality traits, which are at least 50 percent heritable, all of which are rooted in brain processes.. Those factors don’t prove that there are no differences between the brains of the sexes because all of them can be explained, in part due to genetic factors.
These findings, they claim, say that it’s impossible to say what features a person’s brain will have based on the known sex of the brain. With differences in gray matter, brain size and other regions in the brain, we can definitively say whether or not the brain is male or female. Sure some outliers will occur, but the overall bulk, we would see that the sex would be guessed with a super majority being correct.
Joel envisions a future in which individuals are not so routinely classified based on gender alone. “We separate girls and boys, men and women all the time,” she says. “It’s wrong, not just politically, but scientifically – everyone is different.”
Here we are with the point of this article: to attempt to normalize this trend of degenerate behavior that the media pushes which begins to permeate our society. Chromosomal differences between men and women show the sex differences. X means woman, Y means man. Some may point to some anomalies, but anomalies occur in nature all the time and are not a representative of the population.
This also shows with differences in brain size, that causes a difference in IQ between men and women. The study found that men had brains that were, on average, 8 to 13 percent larger than women’s. Since we know that the IQ/brain size correlation is .35, more often than not, men will have higher IQs than women due to having slightly larger brains. And the data is consistent with the finding that men and women have slightly differing IQ scores, which shows in the difference in average brain volume between men and women.
In JP Rushton’s refutation to Steven Jay Gould’s revised edition of The Mismeasure of Man, he states that Gould claims that when accounting for body size and age that the difference in brain size drops from 182 grams to 113 grams, then invokes unspecified age and body size parameters and that accounting for these differences then the sex difference in brain size will vanish. Ankney (1992) reexamined the autopsy data of Ho et al (1980) and found that uncorrected for body size, the difference between men and women’s brains was 140 grams; After correcting for body size, the difference between men and women was 100 grams. This shows that around 30 percent of the difference between men and women in brain size is attributed to body size.
In this review, Rushton did state that men and women had the same scores on tests of intelligence and that this provided a paradox due to the differences in brain size between men and women and similar IQ scores. However, Rushton and Jackson (2006) showed that men and women differ by 3.63 IQ points on average, among a multitude of other strong correlates with the difference in IQ scores.
Men have 23 billion neocortical neurons, women with 19 percent less, at 19 billion (Pakkerson and Gunderson, 1997). Seeing as cortical neuron activity moderates perception in the brain, the differences in neocortical neurons affect other processes and mental faculties in the brain as well.
All of these brain differences then manifest themselves in cultural achievement between men and women.
Charles Murray (2003), in his book Human Accomplishment shows differing societies’ human accomplishments and how these differences in human accomplishment have shaped our society today. He gathered data on women Nobel Prize winners from 1901-2000 and found this:
Murray states on p. 273, 274 and 275 that women have an underrepresentation in the sciences. You would figure, if this so-called “white cis male patriarchy” was out to have women be underrepresented, they wouldn’t have allowed the feminist movement to come full-swing in the early 1900s. Well, the numbers on women Nobel Prize winners from 1901-1950 is: 2 percent sciences total, 4 percent chemistry,2 percent medicine, 2 percent physics and 11 percent literature with a 4 percent representation in total. From 1951-2000, it was 2 percent sciences total, 1 percent chemistry, 4 percent medicine, 1 percent in physics and 8 percent in literature for a total of 3 percent.
Now, this does show women’s high verbal ability at play with regards to the number of literary Nobel Prizes’ they have, but this shows that after the Feminist Movement, that when they got ‘equality’, they failed to produce the same as men. This data corroborates what I noted earlier: that there is a significant amount of cortical neuronal difference between men and women, there is a 3.63 IQ point difference between men and women on average, and finally the data on Nobel Prizes corroborates this information.
The Defense Ministers of Sweden, Norway, the Netherlands, and Germany embody what is going on at the moment in these countries with the ‘migrant’ crisis. We can see with Russia’s aversion to the scenario currently happening in Europe, that with their Defense Minister, these things that are currently happening in those aforementioned countries won’t happen in Russia.
This is shown in how men and women’s overall leadership capabilities, ability to lead meetings and differing managing strategies. All of these differences, of course, are due to brain differences between men and women.
Women are more emotional than men due to biology, so in times of war with a woman Defense Minister, since men and women differ in inductive and deductive reasoning traits, women won’t be deductive, which is a logical process in which a conclusion is drawn from multiple premises that are assumed to be true, which men excel at. Women, however, excel at inductive reasoning, which is making broad generalizations from specific observations. It seems that in war time, deductive reasoning would be better, seeing as the conclusion is drawn from things that are assumed to be true. Men make better leaders than women because, since, on average, men don’t think with their emotions while women do.
Men and women’s brains differ on the individual level, of course, like all things between groups, sexes, and individuals. The push to deny human nature, and in turn, invoke a blank slate argument even in the face of science is shown in the way that our society is headed. Between differences in brain size, scholastic achievement, IQ, brain weight, Nobel Prizes, neocortical neurons and other gender-specific differences, these innate differences in brain structure manifest themselves in society and the types of jobs women want and acquire. Women cannot lead as well as men and while they ‘lead differently’, the best type of leader to have is a man as men think with logic and facts whereas women think with emotion, on average.