Saturday, 9 February 2013

Why are girls and boys maturing earlier?


For girls, the age of puberty has been falling since the 19th century. The same period has seen a similar decline for boys (source)


In the United States and other Western countries, girls have been reaching puberty at earlier and earlier ages. A recent longitudinal study has examined this trend in white Americans born between 1928 and 1992. Its conclusion? Girls are reaching puberty earlier because of an interaction between a lifestyle factor and a pre-existing genetic predisposition:

Our data also show, for the first time, that the effect of menarche SNPs on prepubertal BMI was stronger in children born more recently compared to those born earlier in the century, thereby suggesting that the developmental genetic susceptibility to elevated BMI may have only been ''uncovered'' in the more obesogenic environments of the recent past. (Johnson et al., 2013)

For the study's authors, the lifestyle factor is that girls are eating more, exercising less, and accumulating more body fat. Because fatty tissue is a significant source of estrogen, an increasing percentage of body fat tends to hasten puberty in young girls (Frisch & Revelle, 1970; Frisch & McArthur, 1974; Kaplowitz et al., 2001; Siiteri & MacDonald, 1973). This effect is stronger in girls with a certain genetic background:

It is possible that over the examined time period, individuals with higher genetic burden for accelerated sexual development are for the first time ''allowed'' by liberalization of the environment to alter dietary intake and energy expenditure to support their genetic potential for rapid weight gain and earlier sexual development. (Johnson et al., 2013)

But why are boys too maturing earlier?

In boys, body fat is not linked to early puberty. In fact, there seems to be a negative correlation, perhaps because fatty tissue is a significant source of estrogen (Wang, 2002). Overweight boys often present signs of disrupted male sexual development, e.g., breast budding, higher voice pitch, etc.

Yet boys likewise are reaching puberty at an earlier age. This is the conclusion of a recent American study:

We observed that onset of secondary sexual characteristics in US boys as seen in office practice appears to occur earlier than in previous US studies and the 1969 British study commonly used for pubertal norms. […] White boys in our study entered stage 2 genital growth 1.5 years earlier than the British boys (10.14 vs 11.60 years of age).

[…] These data are consistent with recent trends from other countries, such as Denmark, Sweden, Great Britain, Italy, and China. For example, urban Han Chinese boys achieve a testicular volume of ≥4 mL (13% by age 9) and spermarche earlier than studies conducted several decades ago; Danish boys achieve a testicular volume >3 mL more than 3 months earlier now than 15 years ago. (Herman-Giddens, 2012)

This trend has also been observed in the age when a boy's voice begins to change:

According to records kept by the Leipzig choir, the most common period of voice breaking for male singers in the mid-18th century was between 17.5 and 18.5 years of age (Daw, 1970); in contrast, children enrolled in the Copenhagen Municipal Choir School from 1994-2003 had a median age of voice breaking of 10.4 years (Juul, Magnusdottir, Scheike, Prytz, & Skakkebæk, 2007), which is consistent with the choir's subjective reports of difficulty retaining children as singers past the age of 12 or 13 years. (Mendle & Ferrero, 2012).

This is a challenge for Occam's Razor, and the task is no easier if we look at other possible causes. If the cause isn’t a higher proportion of body fat, could it be a higher level of estrogens and estrogen-like substances in the environment? (see earlier post). Yes, that might hasten puberty in girls and increase accumulation of body fat. But in boys it would delay puberty by offsetting the rising level of male hormones.

In trying to figure out the causal chain of events, we should keep in mind that the relationship between body fat and age of puberty runs in both directions. On the one hand, estrogen from body fat lowers the age of puberty in girls. On the other hand, earlier puberty increases ovarian production of estrogen, which in turn stimulates deposition of body fat, particularly on the hips, buttocks, and breasts (Van Lenthe et al., 1996). So perhaps some unknown factor is causing earlier sexual development in both sexes and thus greater deposition of body fat in girls.

A response to social cues?

This unknown factor might be something in the social environment. As Hawley (2011) argues, humans unconsciously monitor their social environment for reproductive opportunities and accordingly speed up or slow down their pace of sexual development:

[...] human children, especially girls, may be sensitive to their early socioecological conditions in ways that entrain development toward either a faster (earlier pubertal maturation, more sexual partners, less stable relationships) or slower (later pubertal maturation, fewer sexual partners, more stable relationships) life history strategy.

With the transition to post-traditional societies, there has been an increase in the erotic stimuli that preteens encounter in their surroundings:

Common in traditional societies are adult-supervised adolescent initiation ceremonies (Schlegel & Barry, 1980) that are designed to commemorate the transition from childhood to adulthood and inculcate the adolescent with adult values, duties, behaviors, and sex roles associated with the culture (Schlegel, 1973). That is, these adolescents are taught adult sex roles by adults. We now appear to have a complete turnaround. In modern, Western cultures, adolescents derive sexual relationship expectations from television, cable, music, purveyors of racy lingerie (who target teenage girls), and pornography that they can now access on the Internet and thereby carry around on their cell phones. (Hawley, 2011)

Erotic imagery in particular is today available to a degree that was impossible not so long ago. Young boys and girls have virtual access to an endless supply of picture-perfect sexual partners. Whatever the media—films, TV, magazines, the Internet—we're exposed to images that can stimulate sexual desire as efficiently as what normally exists in the real world. More so, in fact. These images are ‘supernormal’ stimuli.

To date, only one study has looked into possible relationships between erotic imagery and pubertal timing:

The aim of this study was to investigate associations between pubertal timing and boys' Internet use, particularly their viewing of pornography. We used a sample comprising of 97 boys in grade 8 (M age, 14.22 years) from two schools in a medium-sized Swedish town. This age should be optimal for differentiating early, on-time, and later-maturing boys. Boys responded to self-report questionnaires on their Internet use and pubertal timing. Early, on-time, and late-maturing boys did not differ in terms of most Internet activities. However, early maturers reported downloading and viewing pornography more often than the other boys did (p<.001). (Skoog et al.,2009)

Admittedly, the arrow of causality might point in the other direction, i.e., early maturing boys have a stronger sex drive and thus a greater interest in porn. This was, in fact, the authors' explanation. We should also remember the well established correlation between early puberty in girls and the absence of a father in the home. It was long thought that father absence triggers early puberty in girls. In fact, a twin study has shown a genetic cause: absent fathers tend to have genes that favor earlier sexual development in their progeny (Mendle et al., 2006).

One might also object that the decline in the age of puberty began long before the Internet. Before the Internet, however, there were porn magazines. And before them, there were pictures garnered from art books, fashion magazines, or the lingerie sections of mail-order catalogues. One could also bring erotic images to mind by reading certain novels. Thus, modern pornography is merely the latest stage of a lengthy co-evolution between, on the one hand, improvements in photography and other imaging technologies and, on the other hand, a weakening of taboos against masturbation. At the beginning of this co-evolution, in the 19th century, masturbation was much less developed among young boys and girls as a sexual lifestyle. Visual aids were scarce and of poor quality, religious injunctions were strong, and adult supervision inside and outside the home was omnipresent.

Conclusion

The age of puberty might be declining because boys and girls are being exposed to ever more and ever better erotic imagery, but this hypothesis needs confirmation by longitudinal studies to determine which is the cause and which is the effect. Another drawback with current research is its focus on the most extreme forms of pornography, such as child porn. Yet the usual stuff is the kind that most people consume ... and in unparalleled quantities. As the authors of a recent Dutch study remarked:

[...] we can only emphasize that Dutch youth are confronted with and expose themselves to an unprecedented amount of R-rated and Xrated material in the media. Research on its consequences for adolescents' sexual socialization is largely missing but, as this study has shown, is urgently needed. (Peter & Valkenberg, 2006)

And erotic imagery isn't confined to X-rated websites or magazines. It is in fact ubiquitous in modern social environments. Girls might accelerate their sexual development by leafing through fashion magazines just as boys might accelerate theirs by viewing porn.

The erotic imagery hypothesis will have to fit the data better than rival hypotheses. Two of these, the body fat and environmental estrogen hypotheses, can explain the decline in the age of puberty for girls but not for boys. Another possible cause is better nutrition. Yet, among white Americans at least, much of this decline has happened since the 1950s—when nutrient levels were already adequate for this population. Finally, there is the possibility that puberty is happening earlier because genes that favor that developmental trajectory are spreading within the population. Modern social environments favor a reproductive strategy of early puberty, low parental investment and, especially, low paternal investment—in short, the ‘cads’ are outbreeding the ‘dads’ (see earlier post).

References

Frisch, R.E., R. Revelle. (1970). Height and weight at menarche and a hypothesis of critical body weights and adolescent events, Science, 169, 397-399.

Frisch, R.E. & J.W. McArthur. (1974). Menstrual cycles: fatness as a determinant of minimum weight necessary for maintenance or onset, Science, 185, 949-951.

Hawley, P.H. (2011). The evolution of adolescence and the adolescence of evolution: The coming of age of humans and the theory about the forces that made them, Journal of Research on Adolescence, 21, 307-316.
http://www.people.ku.edu/~phawley/Publications/Hawley%202011%20JRA%20Evo%20of%20Adol.pdf

Herman-Giddens, M.E., J. Steffes, D. Harris, E. Slora, M. Hussey, S.A. Dowshen, R. Wasserman, J.R. Serwint, L. Smitherman, & E.O. Reiter. (2012). Secondary sexual characteristics in boys: Data from the Pediatric Research in Office Settings Network, Pediatrics, 130, e1058-e1068.
http://pediatrics.aappublications.org/content/130/5/e1058.full.pdf+html

Johnson, W., A.C. Choh, J.E. Curran, S.A. Czerwinski, C. Bellis, T.D. Dyer, J. Blangero, B. Towne, & E.W. Demerath. (2013). Genetic risk for earlier menarche also influences peripubertal body mass index, American Journal of Physical Anthropology, 150, 10-20

Kaplowitz, P.B., E.J. Slora, R.C. Wasserman, S.E. Pedlow & M.E. Herman-Giddens. (2001). Earlier onset of puberty in girls: relation to increased body mass index and race, Pediatrics, 108, 347-353.

Mendle, J. & J. Ferrero. (2012). Detrimental psychological outcomes associated with pubertal timing in adolescent boys, Developmental Review, 32, 49-66.

Mendle, J., E. Turkheimer, B.M. D'Onofrio, S.K. Lynch, R.E. Emery, W.S. Slutske, N.G. Martin. (2006). Family structure and age at menarche: a children-of-twins approach, Developmental Psycholpgy, 42, 533-542.

Peter, J. & P.M. Valkenberg. (2006). Adolescents' exposure to sexually explicit material on the Internet, Communication Research, 33, 178-204.

Siiteri, P.K. & P.C. MacDonald. (1973). Role of extraglandular estrogen in human endocrinology. In S.R. Geiger (ed.), Handbook of Physiology, Washington D.C. American Physiology Society, sect. 7, vol. 2, part 1, pp. 615-629.

Skoog, T., H. Stattin, & M. Kerr. (2009). The role of pubertal timing in what adolescent boys do online, Journal of Research on Adolescence, 19, 1-7.

Van Lenthe, F.J., C.G. Kemper & W. van Mechelen. (1996). Rapid maturation in adolescence results in greater obesity in adulthood: the Amsterdam Growth and Health Study, American Journal of Clinical Nutrition, 64, 18-24.

Wang, Y. (2002).Is obesity associated with early sexual maturation? A comparison of the association in American boys versus girls, Pediatrics, 110, 903-910.

36 comments:

Encyclopediaphile said...

But hasn't the length of adolescence more than doubled? I caught a presentation on this on public access TV about a year ago.

Sister Y said...

A nice test would be to examine puberty changes (if any) in groups that genuinely have markedly lower access to pornography; the only one I'm acquainted with is Chassidic folks, but I'm sure there are other communities that ACTUALLY clamp down on erotic imagery. Do their kids experience the puberty age decline that most kids do?

JayMan said...

I don't really buy the social cues theory. As Sister Y suggests, testing it on populations not exposed to sexually-charged imagery might be worthwhile (if any such group can be found).

Most likely, there are two mechanisms involved, each explaining a part of the curve. The earlier part of the curve, out to about the turn of the 20th century, is likely explained by better nutrition. This need not be excess body fat, just not being actually malnourished doing sensitive periods in youth.

The continued decline after the early 1900s is likely the result of evolution. According to my look at things, dysgenic breeding has been going on for some time. Presumably, lower IQ individuals are earlier-maturers. This appears to be primarily through increased fertility of low-IQ women relative to higher-IQ women.

Beyond Anon said...

but I'm sure there are other communities that ACTUALLY clamp down on erotic imagery

Yes, those weird folks in Pennsylvania, the Amish, would be a candidate.

JayMan said...

Beyond Anon,

Nope, the Amish won't do thanks to their custom of Rumspringa.

M said...

http://www.mhhe.com/socscience/devel/ibank/image/0147.jpg

Menarcheal age round the world.

Lowest in among Mainland Chinese, African Americans and Finns, highest among Africans in Africa.

Anonymous said...

Menarcheal age tends to be lowest in the highest SES groups as well, I think. This is a fairly robust finding.

Urbanisation is also linked to lower menarcheal age (urban earlier than rural).

ErisGuy said...

Young boys and girls have virtual access to an endless supply of picture-perfect sexual partners

Upon reading this comment, I spent the afternoon survey pornographic sites to determine the statement’s veracity. My conclusion: no one familiar with porn can call the women in it picture-perfect. (I can’t judge the men, as the porn I studied tended to show primarily one body part, which seemed exaggerated in size.)

Will S. said...

Bah; I'm more inclined to blame environmental causes: (a) synthetic chemicals that mimic hormones, in the environment, and (b) the effect of birth control pills, which leave female bodies in urine and feces and ultimately enter the water table; we all consume them.

humanvarieties.org said...

Regarding recent evolution, Stearns et al (2010) found that "...both women and men are under selection for earlier age at first birth in both pre-industrial, natural fertility populations and in post-industrial populations."

Nutrition and "over-nutrition" probably go a long way toward explaining the rest. Even if obesity has opposite effects on boys and girls on an individual basis, it's probable that male puberty "chases" female puberty for biological reasons. Girls in your peer group sprouting breasts is a much more natural and immediate cue than sexualized media.

Anonymous said...

Regarding recent evolution, Stearns et al (2010) found that "...both women and men are under selection for earlier age at first birth in both pre-industrial, natural fertility populations and in post-industrial populations."

This is mainly selection for greater fertility in general, right?

There's less of a cost nowadays for greater fertility - your children are unlikely to starve to death like they were in the past - and obviously there are fitness benefits to pumping out as many babies as possible.

Sublime Oblivion said...

Incidentally, this would explain a significant part of the Flynn Effect.

Mangan said...

http://mangans.blogspot.com/2012/11/could-pornification-of-society-cause.html

Ben10 said...

I don't know the answer to the question but i do know that it is going against the natural trend of human evolution for neoteny, increased encephalisation, increased learning abilities and longer age of 'livability'. In short we are reversing the hominizationb trend to become our own more speciated 'gorillas', by reference to the time when gorillas just left the homonization trend but were still close to australopithecus.

Peter Fros_ said...

Encyclopediaphile,

How do you define "adolescence"? My height was still increasing as late as 23 years of age.

Sister Y, Beyond Anon,

It's difficult to find boys who haven't been exposed to porn, even among so-called religious fundamentalists. You would have to look at groups (e.g., Amish, Hassidic Jews, etc.) that have shut out the modern social environment.

Interestingly, a well known researcher has had the same idea:

"the real challenge of such a study is finding a control -- a group of children who have not grown up surrounded by billboards advertising underwear. ''Perhaps Amish children,'' she muses, ''or Mennonites.''

http://www.nytimes.com/2000/12/24/magazine/the-making-of-an-8-year-old-woman.html?pagewanted=all&src=pm

JayMan, Anon, Sublime,

I'm sympathetic to your explanation. In fact, I see it as the only other credible one. The main problem with it is that the decline in the age of puberty doesn't seem to be decelerating, yet there has been a sharp drop, particularly since the 1970s, in the fertility of low-IQ women as a result of easier access to birth control and abortion, and also because of the decline in religious belief within this group.

ErisGuy,

Most erotic imagery is now mainstream and is no longer called "porn". My impression is that the feminine and masculine images one sees in most magazines are better than what one sees in real life.

Will S.,

Yes, but that factor would tend to slow down pubertal development in boys. In reality, the very opposite is happening.

Humanvarieties,

In North America, at least among white Americans, nutrition levels have been adequate since the 1950s. Yet much of the decline in the age of puberty has happened since then. How come?

Mangan,

Yes, that was an excellent post!

Ben,

I'm not so pessimistic. Fertility rates are levelling out by social class, and it even looks like we'll soon see a positive correlation between fertility and socioeconomic status.

Sean said...

There may be something in the pornography exposure idea as far as boys are concerned. Availability of willing women is what is in short supply for males, so images of willing women would be expected to have more effect on accelerating the development of boys.

I think girls' problem is different to boys. Women need to be able to assess qualities more subtle than age and looks, before settling on the man they want as the father of her child. (The formula is supposed to be: get to know several prospective husbands, then settle for the next man who is better than the best of that bunch.)

What's adaptive for girls is to attract many suitable mates, so that they can choose from them. So girls need to be fertile and wised up. Admittedly there might not always be resources for slower development, but as Hawley says, there is more than one way to adaptively solve a problem. Early menarche being brought on through exposure to many image search perfect males; irrespective of the prospects for slower development, would be aimed at mating as quickly as possible. Wouldn't that often be maladaptive, and often lead to a girl being impregnated by a sub par male before she knew better?

Quality of Early Family Relationships and the Timing and Tempo of Puberty: Effects Depend on Biological Sensitivity to Context

Jason Malloy said...

'Human Varieties' was me. It showed up as my name in preview.

In North America, at least among white Americans, nutrition levels have been adequate since the 1950s. Yet much of the decline in the age of puberty has happened since then. How come?

You already answered this. Your post did not present accelerated female puberty as the mystery, but rather accelerated male puberty.

Both subtle and overt sexualized social cues have declined over the last 20 years (Agnostic provides small pieces of evidence for this almost every day). Youthful mating effort has declined, along with the related trend of falling crime (i.e. men are competing less for promiscuous mating opportunities). Age of first intercourse has increased, despite the fact that puberty comes earlier.

If men are developing earlier, its much more plausible that the cue their bodies are responding to is simply earlier female physical development.

One way to test "peers vs porn" might be to look at white, Hispanic, and Asian males in heavily black areas where girls develop earlier. Do white males develop earlier in black areas?

Sean said...

"Age of first intercourse has increased".

For girls in Britain it certainly hasn't, and I find it difficult to understand how it has't fallen for boys. A relative told me among the first year secondary school classmates of her daughter (none older than 12) there were girls having sex. The police quietly stopped prosecuting teenagers for sex with 13 year old girls some time ago . "Thirty years ago, just four per cent of girls aged 17 and under had sex with three or more boys. Today, the figure is 20 per cent, and rising."

There is a trend for teen girls to bleach their nether regions, and even have surgery on their vaginas. That's driven by mens' expectations from exposure to porn; so is the increase in anal sex.

Anonymous said...

Both subtle and overt sexualized social cues have declined over the last 20 years (Agnostic provides small pieces of evidence for this almost every day). Youthful mating effort has declined, along with the related trend of falling crime (i.e. men are competing less for promiscuous mating opportunities). Age of first intercourse has increased, despite the fact that puberty comes earlier.

Agnostic's "data" on this does not seem very reliable. It's very impressionistic, anecdotal, etc.

Anonymous said...

earlier menarche/earlier maturity = increased stupidity. monkeys reach sexual maturity even sooner. same reason black infants reach motor milestones earlier than whites, & asians reach them later - when you have less far to go, you get there more quickly. the flynn effect covers it up. does increased stupidity make earlier menarche or vice versa? some of these data are infected with demographic problems - if there are more blacks & hispanics & fewer asians - that makes it look like ALL people are reaching menarche earlier. the only way environment causes this is by toxins monkeying with hormones - not by looking at pictures! panjoomby

Anonymous said...

"It's difficult to find boys who haven't been exposed to porn"

I think this focus on porn specifically is a red herring. If early maturing does have anything to do with the greater public sexualization of society providing *false* evolutionary cues to mature earlier then the cause will be in the mainstream culture - porn is just piggybacking on Hollywood, MTV and mainstream TV.

.
Secondly i wonder if this process is actually the opposite way round i.e. western civilization artifically *raised* the age of menarche through imposing negative consequences on early maturers e.g. forced celibacy through homes for unmarried mothers.

Assuming an age of menarche bell curve this cultural punishment - necessary for a complex society? - may have pushed the age above its natural level and the destruction of traditional western civilization since the 60s is simply allowing it to drop to a pre-civilization tropical level?

Anonymous said...

Hormones in food may lead to early puberty
http://thegrio.com/2013/02/12/hormones-in-food-may-lead-to-early-puberty/

Anonymous said...

JayMan,

Evolution can work fast, but not this fast. Something cultural/ environmental must be going on here too.

This is like Helmuth Nyborg saying Danish IQ will be ~90 or even lower in a couple of generations, 3 or so, thanks to dysgenics and immigration from the third world (minus East Asia). Thankfully it doesn't happen that fast.

Anonymous said...

"'Ongoing, severe epidemic' of STDs in US, report finds"

http://vitals.nbcnews.com/_news/2013/02/13/16951432-ongoing-severe-epidemic-of-stds-in-us-report-finds

"Just in time for Valentine’s Day, researchers from the U.S. Centers for Disease Control and Prevention issued two new studies of sexually transmitted infections (STIs) today detailing what the lead author of one calls “an ongoing, severe, STI epidemic.”

The studies reveal new infection data, some of it available for the first time, for the eight most common STIs -- chlamydia, gonorrhea, syphilis, herpes, human papillomavirus (HPV), hepatitis B, HIV, and trichomoniasis. The studies, which estimate infection rates and medical costs related to STIs, were published in the journal Sexually Transmitted Diseases.

Both are startling. In 2008, there were 20 million new incidents of infection in the United States, and a prevalence (new infections plus ongoing infection) of 110 million, according to CDC estimates. (Because one person may have more than one infection, the 110 million figure does not mean 110 million people have a sexually transmitted disease.) As a result, the United States incurred estimated direct medical costs of nearly $16 billion.

Previous such estimates, for years 1996 and 2000, estimated approximately 15 million and 18.9 million new incidents respectively, though these reports used somewhat different data sources and methodology so the CDC cautions against making direct comparisons. According to the Henry J. Kaiser Family Foundation, the American Social Health Association, and the CDC, the U.S. has the highest rate of STIs in the industrialized world.

“STIs take a big health and economic toll on men and women in the United States, especially our youth,” CDC epidemiologist Catherine Lindsey Satterwhite, who led the study of incidence and prevalence, told NBC News.

Although people age 15-24 account for only 25 percent of the nation’s sexually experienced population, Satterwhite’s study estimates they account for about half of all sexually transmitted infections."

Onnilk Leymoore said...

As suggested above: That boys are responding to the chemical cues etc of the girls seems best by Occam's razor. That way oestrogen, better nutrition, etc, accounts for the girls' earlier maturing, and that then accounts for the boys' earlier maturing.

But what about a link to lack of sleep, increased exposure to light, increased brain activity over long periods because of the ever-more electronic environment? If there's a brain-clock for maturity based on exposure to light, data, etc, it must be running faster nowadays.

Sean said...

Anon, Nyborg's prediction is far fetched if Danes continue to reproduce with Danes, or at all, at much the same rate as currently. Consider: waves of mainly young male immigrants from the only part of the world that still has high birth-rates, into the world's most liberal country.

Biological sensitivity to context, not the spread of genes may explain it. As Hawley says, Schistocerca gregaria becomes gregarious or solitary in response to the environment.

Anonymous said...

This is like Helmuth Nyborg saying Danish IQ will be ~90 or even lower in a couple of generations, 3 or so, thanks to dysgenics and immigration from the third world (minus East Asia). Thankfully it doesn't happen that fast.

Why not? Detroit's mean IQ fell even more in less than one generation.

Anonymous said...

Any teacher can observe that, in the us public middle schools that 'enjoy' diversity, white girls are the target of interest of the 'minority' male students, while the white boys still show absolutely no interests in the matter and prefer star wars and the like.
This level of interest would easily qualify as 'sexual harassment'. BTW i spent almost 3 years in the US public school as a substitute.
But who are you going to complain to?
The strong Affirmative Action policies have installed a high number of black/minority principals or assistant principals.
So i don't see any substitute going in the office to complain to the black assistant principal that the blond 7th grader girl is harrassed by all the browns in the class.
In fact, after an incident involving a black girl bullying a much smaller white boy, i was myself put in trouble for exposing this fact. The first day when i denounced the girl's behavior, it was followed by zero sanction from the office. The second day the girl repeated her assault on the white boy in front of me and all the class, and i send her, again, to the office with an office referal for the second time.
Guess who was convoked to the principal office? me!
The principal (black) applied all sort of bulshit talk to excuse the behavior of 'his' student (poor socio-economical status blahblah) and pressured me too, suggesting i was insensitive and possibly incompetent to deal with the situation. As you guess my position was clearly jeopardized, just a letter of him and bam, no more job. I did barely talk 20 seconds, but at least i said '...ok, but what about the victim of the bullying?' which somehow closed the interview. Of course i avoided all references to race which would have terminated my job. The same day, the change in behavior form another black assistant was immediate: he looked at me with killer eyes and pure hatred. I don't hate those affirmatively appointed black assistants and teachers. But i just hate to the highest point those who implemented these AA policies and destroy the public education system by using 'diversity'. Affirmative Action is so widespread, it now basicaly rules the hiring process in the faculties.
We know who are these culprits and what they deserve, no need to elaborate on that.

What happens when 'what goes around comes around' and shit hits the fan?
Well, that's the Washington DC school district. Heavily black from students to teachers. Heavily failing grades and humomgus discipline problems (pregnant teenagers, crime, chaos in the classes...). What did the above-not-mentioned culprits decide to do: clean up the excessive incompetency by hiring the ultimate bitch: Michelle Rhee

Her Motto was "there is no reasons WDC students don't perform as well as other students (right, like Swedes or Japaneses...), so it must be the (bad) teachers". The not-mentioned bastards must have thought 'she plays by OUR rules, so let's hire her'. She did a job that no white male chancelor could have done without being accused of racism. So whe was 1)not a man and 2) not white. The teachers shitted in their pants each time she visited their school, as her only job was to fire them. After one year in tenure, the grades improved miraculously as the shit accumulated in the pants of the teachers. Then allegations of fraud were investigated as the rate of 'pencil correction' was 80% higher than usual on the test response sheats. But nothing was confirmed as no teacher admitted he cheated....
Anyway, she left and was rewarded and awarded prestigious distinctions by the not-mentioned, while scapegoats payed for the fraud allegations and her misbehavior, then, 2 or three years later, the student's grades fell back to their initial disastrous level.
http://en.wikipedia.org/wiki/Michelle_Rhee

Anonymous said...

"Age of first intercourse has increased".

You have to compare like with like.

In a lot of these cases you have a situation where the
- white rate is x
- black rate is 2x
- asian rate is x/2

(not precisely but in that order)

so if the black *percentage* of kids goes up then the *average* rate goes up and if the asian percentage goes up the rate comes down without *any* changes within each group.

So you have to make sure you're only comparing the same ethnic group.

.
"The police quietly stopped prosecuting teenagers for sex with 13 year old girls some time ago. "Thirty years ago, just four per cent of girls aged 17 and under had sex with three or more boys. Today, the figure is 20 per cent, and rising.""

This is the point i was making about cultural punishment. If you have 4% early maturers who through cultural constraints only end up with one kid while the late maturers have two then the early maturers stay at a low percentage.

If you take that cultural punishment away and both early and late have the same number then the percentage will increase - maybe not fast enough to explain the change though.

However if you remove the cultural penalty for early maturers and at the same time put negative reprodutive pressure on the late maturers - through taxation, housing costs etc - so now the early maturers have two kids while the late maturers only have one?

The test would be is this change in the age of menarche across the whole SES spectrum of white children or is it skewed to the lower end i.e. is a large decline at the welfare underclass end distorting the average?

.
"This is like Helmuth Nyborg saying Danish IQ will be ~90 or even lower in a couple of generations, 3 or so, thanks to dysgenics and immigration from the third world (minus East Asia). Thankfully it doesn't happen that fast."

It can if the lower IQ is combined with violence as that has an ethnic cleansing effect. It's less about population mixing and more about living space.

Say you have ten neighborhoods, an original population with an average IQ of 100 and an incoming population with an average IQ of 90. If the 90 IQ population is also more violent then it's less a case of the two population's mixing as the first population being chased out.

The incoming population then expands rapidly to fill the space while the original population shrinks to the size of the remaining 9 neighborhoods. This process is then repeated in a second neigborhood and then a third etc.

So after the third iteration you don't have a mixed population with some new average IQ between 90 and 100 what you get is three, say 20% admixed, neighborhoods with an average of say 92 and seven remaining neighborhoods who still have the original average of 100.

This process can happen very fast and *speeds up* over time because internal migration by previous arrivals (trying to escape their own group's violence) is added to continuing immigration.

By the time the neighborhoods are 50/50 (still with fairly low admixture) the new average IQ across the ten neigborhoods (5x92+5x100) is 96.

And getting to the 50/50 point takes about 50 years (if the level of violence is high enough and if nothing is done to prevent it.)

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"This level of interest would easily qualify as 'sexual harassment'. BTW i spent almost 3 years in the US public school as a substitute. But who are you going to complain to?"

Quite. What's allowed to happen in white-minority public schools is truely evil. If the media ever started telling the truth - not that that is remotely likely - most people wouldn't believe what those "nice" liberal teachers have covered up.

Sean said...

Robin Dunbar says pair bonding in humans (and some South American monkey species) is for protection against constant sexual harassment (which is surely a type of stress). Maybe that is why a female child in a highly sexualised environment is precipitated into earlier puberty.

Anonymous said...

"And getting to the 50/50 point takes about 50 years (if the level of violence is high enough and if nothing is done to prevent it.)"

That's from a standing start i.e. places like Denmark which imported the problem from scratch.

Sean said...

Middle school is 13 or 14 right? I'd say being a geek with lack of interest in approaching girls (or even being intimidated out of approaching them by classmates) may be due to just Masturbating Too Much. Read about where masturbation does not exist, and married middle aged men men do it with their wives 4 times a night here. (It's in Africa, in case you didn't guess). Some ideas about plasticity and exposure to erotic imagery here.

Based on a study of matings in Quebec, Dunbar says without contraception there would be equilibrium between cads and dads as the pay-off times the frequency is the same. Hence the proportion of cads is not sensitive to the social environment; it's an ancient baseline willingness of women to mate with men who won't commit, or already have a wife, that is the crucial factor.

Wouldn't contraception be a problem for cads, and have slowed, if not stopped, their genes spreading? A related point is that women impregnated when cheating on their regular sexual partner are more likely to have unsuccessful pregnancies, according to this.

szopeno said...

What about the fact that in the past the children were working, while now they are mostly watching tv? I mean in the past there was a lot of work in the houses, which was not done by the wives, but by the children (or hired stuff), like cleaning, washing, etc. How hard work is impacting the maturation rates?

Anonymous said...

"Middle school is 13 or 14 right?"

The cut-offs vary from place to place. In the UK the first cut-off is 11-12 so you have one set of children just starting puberty at 11-12 - hence the reason for the cutoff point i assume - mixed with children who started earlier and are already sexually mature leading to the pre-pubescent 8-10 year olds being preyed on to a certain extent - not entirely with malice aforethought as the children doing the preying might not be entirely aware of what they're doing.

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"(It's in Africa, in case you didn't guess)."

Homosexuals in the west are a bit like that too. I wonder if a virus could be adaptive in the tropics and maladaptive elsewhere?

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"Hence the proportion of cads is not sensitive to the social environment;"

This is obviously nonsense. The proportion of cads must vary by the social consequences of infidelity. It can't possibly not vary. There may be a minimum created by diminishing returns on social sanctions but it can't not vary.

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"it's an ancient baseline willingness of women to mate with men who won't commit, or already have a wife, that is the crucial factor."

Back in the real world the cads mostly get young and/or naive and/or stupid girls pregnant so that's your baseline. However assuming that is a constant then the real baseline will be how protected those young and naive girls are from the consequences of being young and naive.

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"Wouldn't contraception be a problem for cads, and have slowed, if not stopped, their genes spreading?"

It would be, is and has done hence why they are more prevalent in environments where male provisioning isn't necessary e.g. the welfare underclass.

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"A related point is that women impregnated when cheating on their regular sexual partner are more likely to have unsuccessful pregnancies, according to this."

Certainly more likely to have an abortion and pretend it was a miscarriage.

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I think the modern welfare and to an extent alimony environment has partially recreated the tropical environment and as a result people are drawing a straight line in between the two in terms of behavior but the tropical / welfare pattern described makes absolutely no sense in the environment in between those two points.

Sean said...

Re the idea floated in the post that earlier sexual development in is the cause of greater deposition of body fat in girls, rather than stress as suggested by 'Quality of Early Family Relationships and the Timing and Tempo of Puberty: Effects Depend on Biological Sensitivity to Context'. Those who produce more cortisol levels in respose to stress eat more fat and sugar rich food according to Dr. Lustig Cortisol deposits fat around the waist (visceral obesity, which is mainly significant as a marker for fatty infiltration of the liver). Percent Body Fat at Age 5 Predicts Earlier Pubertal Development Among Girls at Age 9 "[G]irls showing larger increases in percent body fat from 5 to 9 years of age, and larger increases in waist circumference from 7 to 9 years of age, were more likely to exhibit earlier pubertal development at 9 years."

So the earlier developing girls had a distribution of fat indicating cortisol rather than estrogen, because as post says, estrogen puts subcutanious fat on the breasts, hips and thighs, not on the waist. Hence comfort eating in response to stressful home life (for those biologically sensitive) seems to be implicated, in girls at least. Dunbar says a big waisted mother has is not adaptive for the health or IQ of the child, but suggests it could be adaptive in a population that was undernourished. See here.

Anonymous said...

There hasn't been any positive correlations between SES and birthrates.

Low SES = Immigrants (mostly Hispanic) and Blacks

For immigrants their birthrates have fallen due to the economic recession, and blacks are always aborting their offspring, so these low IQ women are definitely not having children.

We have some white liberal women/SWPL who have 3-4 kids but these are outliers, a spike, and aren't creating a trend. Most of them have 2 kids at most.

Most white babies are still being born by lower class white women.

I think when you say low IQ women are having less children (aka below replacement) you mean Hispanic illegals and Blacks, because that is were the birthrates have fallen.

Working class white women are still have babies near and above replacement level.