Showing posts with label Rushton. Show all posts
Showing posts with label Rushton. Show all posts

Racial and ethnic variation in penis size, pt. 2: the actual data

Here is most of the relevant published data I know of (but keep in mind the issues touched on in the previous post):

My impression:

  • While there are probably some real differences between populations, differences among different Caucasoid and Negroid populations, at least, appear to be greater than any overall differences between macroraces. I don't find this surprising, since if we looked at, say, height, the same would probably be true.
  • I'm not convinced the data support any difference between Northern Europeans and West Africans, and if differences exist, they are relatively minor.
  • To the extent we can say anything about intra-Caucasoid differences, there appears to be a trend of declining penis size from Northern/western Europe towards SE Europe, the Middle East, and South Asia.
  • Reported values for East Asia do appear to tend toward the low end among worldwide populations.

Related posts:

Racial and ethnic variation in penis size, pt. 1: some background

A few years ago, a "World Penis Size Map" [1] citing a website containing largely made-up numbers [2] entered widespread circulation. Despite being an obvious and inept hoax, it has continued to take in various people, including the press, some economist [3], and Richard Lynn [4]. I started writing up a post at the time, but never bothered to finish it.

Most recently, a presenter at the 2015 London Conference on Intelligence has attempted to defend this hoax data, claiming:

  • Lynn (2013) attempted to resolve the controversy by obtaining data from the World Penis Website, which listed average national penis lengths based on various sources. Using this, Lynn extended Rushton?s model, based on this, to other races, and found that their average penis sizes differed as Differential K would predict.
  • This paper was ridiculed, most notably by a psychologist blogger called Scott McGreal, who pointed out various minor mistakes on the World Penis Website, insisting all its contents was suspect and not properly reviewed
  • As I am researching a book that extends Rushton?s theory to 12 races, I was very interested in Lynn?s penis data. It occurred to me that we can test the validity of Lynn?s national penis lengths by seeing if they correlated with other national measures androgen in the expected direction.
But the website does not just feature a few "minor mistakes". Most of the data is simply made up. One can't "validate" made-up numbers by attempting to correlate them with other putative markers of androgen exposure.

Black men have lower sperm counts than white men

Semen parameters in fertile US men: the Study for Future Families

The Study for Future Families (SFF) recruited men who were partners of pregnant women attending prenatal clinics in Los Angeles CA, Minneapolis MN, Columbia MO, New York City NY and Iowa City IA. Semen samples were collected on site from 763 men (73% White, 15% Hispanic/Latino, 7% Black and 5% Asian or other ethnic group) using strict quality control and well-defined protocols. [. . .] Black men had significantly lower semen volume, sperm concentration and total motile sperm counts than White and Hispanic/Latino men.
This is consistent with the other evidence I'm aware of. Lower sperm counts have been noted in Africa, and a study in Rochester, NY, that included a small number of American blacks similarly found:
All sperm parameters were significantly lower in the small subgroup (n = 7) of African-American men compared with other men in this population (p-values for sperm parameters, < 0.001 to 0.016).
Also consistent with these results: the only autopsy studies I'm aware of (at least one of which Rushton knew of before he became selectively forgetful) both suggest black men have smaller/lighter testes than white men.

No evidence for higher testosterone in black compared to white adolescent males

Racial/ethnic differences in serum sex steroid hormone concentrations in US adolescent males. Cancer Causes & Control. April 2013, Volume 24, Issue 4, pp 817-826

OBJECTIVE: Contrary to the hypothesis that the racial/ethnic disparity in prostate cancer has a hormonal basis, we did not observe a difference in serum testosterone concentration between non-Hispanic black and white men in the Third National Health and Nutrition Examination Survey (NHANES III), although non-Hispanic black men had a higher estradiol level. Unexpectedly, Mexican–American men had the highest testosterone level. Next, we evaluated whether the same patterns are observed during adolescence, the time of prostate maturation.

METHODS: We measured serum testosterone, estradiol, and sex hormone-binding globulin (SHBG) by immunoassay in 134 males aged 12–19 in NHANES III. Mean concentrations were compared by race/ethnicity adjusting for age, Tanner stage, percent body fat, waist, physical activity, tobacco smoke, and the other hormones.

RESULTS: After multivariable adjustment, in the 12–15-year-old males, testosterone concentration was lower in non-Hispanic blacks than whites (p = 0.043), SHBG concentration did not significantly differ between the two groups. Mexican–Americans had the highest testosterone (versus non-Hispanic black: p = 0.002) and lowest SHBG (versus non-Hispanic white: p = 0.010; versus non-Hispanic black: p = 0.047) concentrations. Estradiol concentration was lower in non-Hispanic blacks (p = 0.11) and Mexican–Americans (p = 0.033) compared with non-Hispanic whites. After multivariable adjustment, in the 16–19-year-old males, testosterone, estradiol, and SHBG concentrations did not differ between non-Hispanic blacks and whites. Mexican–Americans had the highest testosterone concentration (versus non-Hispanic white: p = 0.08), but did not differ from the other groups on estradiol and SHBG concentrations. In both age groups, these patterns were generally present, but less pronounced after adjusting for age and Tanner stage only.

CONCLUSION: In adolescent males, non-Hispanic blacks did not have a higher testosterone concentration than non-Hispanic whites, and Mexican–Americans had the highest testosterone concentration, patterns similar to adult males.

This sample is not large, and some of the statistical adjustments may be questionable. But others have also failed to find black-white differences in testosterone among adolescents in unadjusted NHANES data; nor were they seen in a larger study of adolescents,

Steroid hormones during puberty: racial (black-white) differences in androstenedione and estradiol--the Bogalusa Heart Study.

A large biracial cross-section of 1038 healthy children aged 6-18 yr with 519 blacks, 519 whites, 678 males, and 360 females was evaluated for Tanner stage and serum levels of androstenedione, dehydroepiandrosterone- sulfate, estradiol, progesterone, and testosterone. The anthropometric values of the blacks and whites were very similar at each Tanner stage with only minor differences in age, height, and weight related to an earlier onset of puberty in blacks. The hormones dehydroepiandrosterone- sulfate, progesterone, and testosterone did not exhibit any racial differences. Estradiol showed a significantly higher level among black males compared to white males (P 5 0.05) whereas androstenedione was significantly higher in both white males (P = 0.0001) and females (P I 0.01) compared with blacks.

Carleton S. Coon on the endocrine system and racial differences in temperament

In the final chapter of his final book (the posthumously published Racial Adaptations), Carleton Coon discusses possible hormonal substrates of racial differences in behavior. I find Coon's proposals more interesting (and more empirically-grounded) than those of individuals inspired by Rushton to attribute all racial differences to supposed neatly-ordered differences in testosterone. Coon:
[Testosterone] is an element in aggressiveness, territoriality, and hoarding. Blended with adrenaline and smoothed over with cool judgment, it has marked the history of the Caucasoids in many parts of the world.
More excerpts within (continue reading).

"Oversized" Penile Length In The Black People; Myth Or Reality

Guy White "logic": reporting on an incident of bestiality which he asserts "does carry several stereotypes", one of the first three things that comes to guywhite's mind is: "This Black guy must be enormous down under to be able to do it with a horse." Reality:
“Oversized” Penile Length In The Black People; Myth Or Reality
JC Orakwe, GU Ebuh
Abstract
Objective: Amongst the Caucasians and some non-Black races, there is the popular belief that the black people generally have longer penile sizes. Even the Blacks themselves tend to believe so. This study was carried out to test the veracity of this ascription of “oversized” penile length to people of the Black (Negro) race.
Design: A prospective and comparative study
Setting: The Nnamdi Azikiwe University Teaching Hospital, Nnewi, Nigeria.
Subjects and Method: Full-stretch flaccid penile lengths, and flaccid penile lengths, were measured in 115 adult men of the Black race in Nigeria. The results were compared with reported similar main studies on people of other races, which were accessible to the authors. These studies were done in Italy, Greece, Korea, Britain, and the United States of America.
Result: The mean full-stretch penile length of the Nigerian Blacks was 13.37cm and the mean flaccid length was 9.36cm. Similar studies reported full-stretch penile lengths of 12.50cm in Italians, 12.18cm in Greeks, 9.6cm in Koreans, 13cm in British Caucasians [note: the number reported for the British sample is actually the median, and is identical to the median for this Nigerian sample], and 12.45cm in the American Caucasians [note: this sample actually includes Asians, blacks, and whites]. The penile length for Nigerian Blacks was longer than those of the other races, but the differences were only statistically different in comparison with the Koreans.
Conclusion: There is the possibility of racial differences in penile sizes, but there is no convincing scientific background to support the ascription of bigger penile dimensions to people of the Black race
Keywords: Penile Length, Black Race, Penile Size
Tropical Journal of Medical Research Vol. 11 (1) 2007: pp. 16-18

[. . .] The observed longer flaccid penile length particularly may be partly responsible for the apparent impression that the Blacks have bigger penile dimensions. It is know that the flaccid penis is deformable extensible and elastic, and influenced by variations in ambient temperatures, and also by fear and anxiety. This influence may be due to the effect of these factors on the Dartos muscles, which contract in low temperature and in state of fear and anxiety, and relax in high temperatures. Native black environments have high ambient temperatures. Photographs taken in these environments may depict an apparently longer penile length in the flaccid state and this may erroneously be extrapolated to the erect state. We believe that most impressions of the "oversized" penile lengths in the blacks are derived from such pornographic photographs. This however may not be all the reason. Edward in the result of his survey of definitive penile size published on-line, observed that the average flaccid penile length of the black Americans was shorter compared to that of the American Caucasians, but that the average erect length of the American Caucasians was surprisingly longer. Since the comparison was done in the same environment, other factors may be contributory to the observed longer flaccid penile length in the blacks.

Related posts [updated 5/2015]:

The Androgen Receptor and "masculinization"

A question from the comments:
Do you know if T sensitivity has been examined for differences by race? For example, imagine that blacks produced twice as much of the T receptor. This should get them somewhat more masculinization at the same concentration of T.
What I think is undeniable is that "masculinization" is not simply a function of circulating testosterone levels and Rushton's notion of testosterone as a "master switch" that neatly explains myriad racial differences is overly simplistic at best.

Racial variation exists in the Androgen Receptor gene, but there's no reason to assume this variation underlies global differences in "T sensitivity" between races, or that racial differences in "masculinization" in a given domain should imply similar racial differences in masculinization in every other domains. Ultimately, the androgen/AR pathway signals/regulates genes, which themselves vary between populations. Without knowing what's happening downstream of the AR, racial differences in the AR gene are not terribly informative.

To give a concrete example of variation in the AR gene failing to predict a racial difference in a phenotype:

The most-studied polymorphism on the Androgen Receptor gene is a CAG repeat found to be "inversely correlated with transcriptional activity by the androgen receptor". Blacks average fewer repeats than whites, implying increased transcription by the AR in blacks. Intra-racially, a lower number of CAG repeats is associated with higher sperm concentrations. If those facts led you to predict black men have higher sperm counts than white men, you predicted wrong.
Could the differences in sperm concentration in various geographical areas be related to the ethnic origin of the studied populations? From the results shown in Table 3 it seems that the MSC of healthy men might be lower in Africa and South East Asia compared to other parts of the world.
[Semen quality and male reproductive health: the controversy about human sperm concentration decline]

The mean sperm density among the fertile population in this series was 71.2 million/ml which is statistically greater than the value of 46.8 million/ ml observed in the infertile marriage population (P<0.001). The mean sperm count reported in the literature for the Caucasian fertile population is higher, with a range between 79-137 million/ ml [Seminal analysis in fertile and infertile Nigerian men]
I'm unable to find direct comparisons between white Americans and American blacks, but the evidence I'm aware of is consistent with lower sperm counts in the latter: autopsy weighing indicates American blacks have smaller testes than whites. Another autopsy study:
For these preliminary studies, testes from five non-Hispanic Caucasian, five Hispanic, and five African American males of ages 28.2 ± 1.3, 27.8 ± 1.6, and 28.2 ± 1.3 years, respectively, were evaluated. Based on this small sample of men, there were no statistical differences among groups, respectively, for paired parenchymal weight (44.8 ± 5.3, 40.7 ± 1.8, and 34.8 ± 4.6 g), for daily sperm production per gram of testicular parenchyma (4.9 ± 0.3, 5.1 ± 0.7, and 4.3 ± 0.5 X 106/g), or for daily sperm production per man (224 ± 36, 211 ± 35, and 157 ± 33 X 106).
These findings are not statistically significant due to the very small sample sizes, but they are consistent with the other evidence.

Testosterone miscellany

Some trivia, apropos of nothing in particular. I've formed no strong opinion on the validity of the individual claims below, but these excerpts do reinforce for me the following:

(1) Androgens aren't all the same.
(2) Androgens don't make you dumb.
(3) Androgens don't make you criminal or anti-social (at least, they don't make you economically unsuccessful, on average).

Rushton's notion of "testosterone" as a "master switch" that neatly explains various racial differences has never been well-supported by the evidence. Despite this, the idea (which Rushton himself proposed only as a possibility) has been lapped up and internalized as perfectly obvious fact by untold numbers of "hbd" types and racialists.

If a hairy man becomes insatiably curious about what it means to have all that hair, he may well run across the work of Dr AG Alias. (Yes, that is his name.) Alias is an expert on certain aspects and implications of the hairiness of men. He has taken a special interest in hairy military leaders, hairy intelligentsia, low-ranked hairy boxers, and Marlon Brando. Last year he wrote this shorthand version of his views:

"I am fairly certain that the vast majority of hairy/hirsute men, compared to the respective 'much less' hirsute men of the same race and ethnic group, are strikingly more intelligent and/or educated, but only from a statistical point of view."

Male hairiness enjoys a complex and often unclear relationship with intelligence and behaviour. Alias, based at the Chester Mental Health Centre, in Chester, Illinois, has tried to tease out a few of the many subtleties. His reports have been published in Biological Psychiatry, Medical Hypotheses, Schizophrenia Research, and other medical journals that do not fear hairy questions.

Alias attracted attention in 1996 when he presented a paper called A Statistical Association Between Liberal Body Hair Growth and Intelligence to the Eighth Congress of the Association of European Psychiatrists, in London. He reported that hairiness is common among successful male academics, engineers, and physicians - and also among the men who join Mensa.

This was just a year after Alias had published a paper titled Top Ranked Boxers Are Less Hirsute Than Lower Level Boxers. In it, he discusses mesomorphs - big-boned, muscular men. Dr Alias carefully analysed 380 drawings in William Sheldon's book Atlas of Men. This was to gain a general understanding of whether big brutes have lots of body hair.

Alias then carefully examined Harry Mullen's tome Great Book Of Boxing, in which "body hair-revealing pictures are printed of 49 top-ranked, white heavyweight boxers, 15 of whom became world champions". Alias concluded that, as a rule, champions were less hairy than non-champions. However, he cautions that the difference is not statistically significant.
[Marc Abrahams; Hirsute pursuits; guardian.co.uk, Tuesday 28 September 2004 02.17 BST ; link]


[A . Alias. Top ranked boxers are less hirsute than lower level boxers: An example for the importance of 5?-reductase?. Biological Psychiatry , Volume 37 , Issue 9 , Pages 612 - 613. http://dx.doi.org/10.1016/0006-3223(95)94485-F]


Higher body hair with lower mesmorphism ratings were observed in Caucasian homosexual men compared with the general male population, reflecting elevated 5alpha-reductase (5alphaR) activity, and higher dihydrotestosterone-to-testosterone (DHT-to-T) ratio, in sharp contrast to 46,XY 5alphaR 2 deficiency subjects, who are often born with ambiguous, or female genitalia, but tend to grow up to be muscular, heterosexual men with very little body hair, or beard. One study also showed them scoring around dull normal IQs. A greater prevalence of liberal body hair growth in men with higher IQs and/or educational levels was also observed in several samples. The exceptions to this statistical trend are too unsettling, however. Nevertheless, the results of a number of published studies, including one showing higher DHT-to-T ratio in homosexual men, done with different objectives over a span of 80 years, together strongly support these findings. Furthermore, in an animal model, "cognitive-enhancing effects" of "5alpha-reduced androgen [metabolites]" were recently demonstrated.
[Alias AG. A role for 5alpha-reductase activity in the development of male homosexuality? Ann N Y Acad Sci. 2004 Dec;1032:237-44. link]

According to Erik at femininebeauty.info, a plot of mesomorphism ratings vs. body hair ratings for male Caucasian samples from Sheldon shows: "Starting from an effeminate physical build, as the physique becomes naturally more masculine, body hairiness increases, which appears intuitive, but beyond a certain point, greater body hairiness corresponds to a weaker physical build."
Objective: To document the relative importance of endogenous sex steroids in modulating the frequency of orgasms, the dominant aspect of sexual behaviour in healthy eugonadal men.
Design: Measurement of adrenal and testicular sex steroids in a sample of army recruits and study of their relation to frequency of orgasms ascertained by questionnaire after potential confounding variables were controlled for.
Setting: Military campus and military hospital laboratories in Athens, Greece.
Subjects: 92 consecutively enrolled healthy male recruits aged 18-22 years.
Main outcome measures: Weekly number of orgasms. Serum concentrations of testosterone, dehydroepiandrosterone sulphate, dihydrotestosterone, oestradiol, oestrone, {delta}-4-androstenedione, and sex hormone binding globulin.
Results: Serum dihydrotestosterone concentration was the only independent hormonal predictor of the frequency of orgasms; an increase in concentration of 1.36 nmol/l (about 2 SD) corresponded to an average increase of one orgasm a week.
Conclusions: Differences in concentrations of circulating dihydrotestosterone within the normal range may represent a major predictor of sexual activity in healthy young men.
[BMJ 1995;310:1289-1291 (20 May); Contribution of dihydrotestosterone to male sexual behaviour; Mantzoros, CS and Dimitrios Trichopoulos; link]


Associational loosening, slow and faulty information processing, poor gating of irrelevant stimuli, poor ability to shift attention, poor working memory, passivity, ambivalence, anhedonia, and impaired motor coordination are cardinal features of schizophrenia but, unlike delusions and hallucinations, they are related more to negative/deficit symptoms. As summarized by Bass, numerous studies have correlated leadership with 'ambition, initiative and persistence' (opposite of passivity), 'speed and accuracy of thought', 'finality of decision,' or decisiveness (the opposite of ambivalence), 'mood control, optimism and sense of humor' (opposite of anhedonia), etc. Andreasen et al postulate that a disruption in the circuitry among nodes located in the prefrontal regions, the thalamic nuclei, and the cerebellum produces 'cognitive dysmetria', meaning difficulty in prioritizing, coordinating, and responding to information, and that it can account for the broad diversity of symptoms of schizophrenia. A relationship between cognitive processes and cerebellar and basal ganglia functions, and a role of neocerebellum in rapidly shifting attention, have been demonstrated. The cognitive styles, including a proficiency to quickly shift attention, of several famous leaders are used as examples of this contrasting model. Julius Caesar and Napoleon, for instance, could dictate to up to six secretaries simultaneously, using their exceptional working memories, and proficiency in quickly and effortlessly shifting attention while flawlessly gating irrelevant external and internal stimuli. It is suggested that specific brain imaging studies could illustrate this contrast. Gray et al noted positive correlations between 'dominance', an important leadership trait, and serum levels of dehydroepiandrosterone (DHEA) and testosterone (T), but not of more potent dihydrotestosterone (DHT), in over 1700 older men. Though not scientifically rigorous, the author noted positive correlations (P = 0.0162) between the self-rated ratings of voice depth (promoted by T) and of leadership, but none between those of body hair (DHT dependent) and of leadership in 47 male US National Academy of Sciences members. And 43 male US Senators had deeper voices than 36 male House members (P<0.01) who, in turn, had deeper voices than either of two groups (numbers 102 and 72) of male scientists (P<0.01). Therapeutically, before chlorpromazine, DHEA had been used in young schizophrenics with modest success in improving deficit symptoms. DHEA, or other sex hormones, or some of their natural and synthetic derivatives may prove to be valuable to treat deficit symptoms of schizophrenia in both sexes. Copyright 2000 Harcourt Publishers Ltd. [Alias AG. Schizotypy and leadership: a contrasting model for deficit symptoms, and a possible therapeutic role for sex hormones. Med Hypotheses. 2000 Apr;54(4):537-52. link]


Controlling for other variables, age and BMI were associated with lower bioavailable testosterone levels, whereas PCS12, smoking status, and higher SES were associated with higher bioavailable testosterone levels. [Table 2 shows SES (socioeconomic status) correlates 0.12 with bioavailable testostorone, 0.14 with DHEAS, and 0.00 with DHT.]
[Litman HJ et al. Serum androgen levels in black, Hispanic, and white men. J Clin Endocrinol Metab. 2006 Nov;91(11):4326-34. Epub 2006 Aug 15. link]

The result reported in the final study above is opposite the (small) negative correlation between T and SES claimed by Mazur, but Mazur's comments still apply:
The reliable association of high T with antisocial behaviors, including marital disruption and violent criminality, raises an interesting puzzle. These negative behaviors foster downward social mobility. Under the basal model, which assumes T level to be a persistent trait, we should expect an accumulation of high T men in the lower ranks of society. Indeed, as we have noted, correlations between T and various measures of socioeconomic status (occupation, income, education) are significantly negative. But they are slight in magnitude. Thus, leaving aside honor subcultures, we find little concentration of men with high T in the lower classes. Why not? One possibility is that the downward flow of high T men who are antisocial is nearly balanced by an upward flow of high T men who are prosocial. This hypothetical stream of prosocial high-T men remains invisible to us, so far, perhaps because past studies have used as subjects mostly working class men or convicts, who have limited opportunities for legitimate advancement.

The nearly uniform distribution of T across social classes is less puzzling under the reciprocal model, which regards T as malleable rather than a stable personality trait. Again excepting honor subcultures, where challenges are exceptionally common, dominance contests probably occur nearly as frequently among elites as in the working class, as often in the boardroom as on the shop floor. Therefore, T responses to challenge, and to winning and losing, should be distributed fairly evenly across classes. Under this reciprocal model, we would expect little accumulation of T at the bottom levels of society.

Balls and brains

That's The Economist's headline:
The quality of a man’s sperm depends on how intelligent he is, and vice versa

THERE are few better ways of upsetting a certain sort of politically correct person than to suggest that intelligence (or, rather, the variation in intelligence between individuals) is under genetic control. That, however, is one implication of a paper about to be published in Intelligence by Rosalind Arden of King’s College, London, and her colleagues. Another is that brainy people are intrinsically healthier than those less intellectually endowed. And the third, a consequence of the second, is that intelligence is sexy. The most surprising thing of all, though, is that these results have emerged from an unrelated study of the quality of men’s sperm.

[. . .]

Ms Arden found 425 cases where samples had been collected and analysed from unvasectomised men who had managed to avoid spilling their seed during the collection process and had answered all the necessary questions for her to test her hypothesis, namely that their g values would correlate with all three measures of their sperm quality.

They did. Moreover, neither age nor any obvious confounding variable that might have been a consequence of intelligent decisions about health (obesity, smoking, drinking and drug use) had any effect on the result. Brainy men, it seems, do have better sperm.

By implication, therefore, they have fitter bodies over all, at least in the Darwinian sense of fitness, namely the ability to survive, to attract mates and to produce offspring. That is an important finding. Hitherto, biologists have tended to disaggregate the idea of fitness into a series of adaptations that are more or less independent of each other. This work adds to the idea of a general fitness factor, f, that is similar in concept to g—and of which g is one manifestation. To him that hath, in other words, shall be given. Unfortunately for the politically correct, Dr Miller’s hypothesis looks stronger by the day.

Dienekes links to the study. While the result has no direct bearing on Rushton's cross-racial claims (which stand or fall on their own merits), it seems to contradict the broader theoretical underpinning of Race, Evolution, and Behavior, proving that intelligence and reproductive potential need not be inversely related in humans (at least in men).

Related: Physical correlates of cognitive ability

Rushton and genital size: one more time

J. Philippe Rushton asserts [1]:
Orientals are the most K, Blacks are the most r, and Whites fall in between. Being more r means: [. . .] more developed primary sexual characteristics (size of penis, vagina, testes, ovaries)
Rushton apparently has many convinced the above assertions are ironclad facts. They are not. Despite Rushton's sometimes selective presentation of evidence, what data exist (on "size of penis, vagina, testes") fail to consistently align with Rushton's Asian < White < African framework.

Penis size

Rushton claims [2]:

We averaged the ethnographic data on erect penis and found the means to approximate:
Orientals, 4 to 5.5 in. in length and 1.25 in. in diameter;
Caucasians, 5.5 to 6 in. in length and 1.5 in. in diameter;
blacks, 6.25 to 8 in. in length and 2 in. in diameter.
The numbers above are apparently lifted directly (or indirectly via Coon's Racial Adaptations) from a book by "A French Army Surgeon" ("Jacobus X" / Jacobus Sutor) published in 1898 (so much for "averages" of "the ethnographic data"; Rushton cites "A French Army Surgeon" as merely an "e.g." of "the ethnographic record", but Rushton's "ethnographic record" is apparently limited to the supposed observations of a single 19th-century individual).

The numbers given for blacks (ranging up to "8 in. in length" for population means) are implausible on their face, and no modern study of blacks comes close to supporting anything but the very low end of that suggested range.

A study of Nigerians (n=115) finds "mean [stretched] penile length was 13.37 cm [5.26 inches] with a median of 13 cm" [3]. Another study, on 320 Nigerians, finds "average [presumably flaccid] length of the penis (81.6 +/- 0.94 mm); circumference of the penis (88.3 +/- 0.02 mm)" [4].

The Kinsey data, which may be less than ideal but which are cited by Rushton both directly and indirectly, suggest any difference in mean penile dimensions between black and white men in America is measurable in fractions of an inch:
White males had an average flaccid penis length of 4.0 inches, whereas the average black male's detumescent member measured 4.3 inches. But when erect, the average white penis was 6.2 inches long, whereas the average black's was 6.3 inches--still longer, but not by much. (Average circumference for whites was 3.7 inches; for blacks, 3.8.)

When Rushton cites WHO condom standards in support of his theory, he is merely indirectly referencing the Kinsey data (plus a sample from Thailand, and one from Australia). WHO did no original research. Their sole "African" sample is the American black sample from Kinsey [7].

[Update: Rushton claims the WHO specify three condom sizes [1]:
The World Health Organization Guidelines specify a 49-mm-width condom for Asia, a 52-mm-width for North America and Europe, and a 53-mm-width for Africa.
I'd taken Rushton at his word here and had not bothered to check his WHO claim beyond determining that WHO did no original research on the subject (as stated above). In reality, it's clear from the guidelines that WHO specify exactly two widths [7]:
WHO specifies a width of 49 mm or 53 mm with a tolerance of ±2 for individual condoms and ±1 for the average of the lot.
The WHO don't make distinctions among Europe, Africa, and Asia, but between Asia and everyone else [7]:
Condoms are made in various widths. Based on studies in Australia, Thailand and the USA, and the experience of major agencies, the wider condoms (flat width 52-55 mm) will be preferred in Australia, Africa, Europe, Latin America, the Middle East and North America, and the narrower condoms (47-51 mm) will be preferred in several Asian countries (see Appendix III). Other widths are also made for small specialized markets.
Note: the ranges encompass tolerances in the specification; only two distinct widths are specified.]

Testes size

Rushton reviews most of the evidence of which I'm aware in his 1987 paper [2]:
Measurements taken from living subjects as well as those at autopsy, show the size of testes is twofold lower in Asian men than Europeans (9 g vs 21 g), a difference too large to be accounted for entirely in terms of body size (Diamond, 1986; Short, 1984). [. . .] Contrary to the general trend, Freeman (1934) observed that, at autopsy, American blacks had less heavy testes than American whites (13g vs 15g). [. . .] Subsequently Daniel, Fienstein, Howard-Peebles, and Baxley (1982) found no black-white difference in testicular volume among American adolescents, while Ajmani, Jain, and Saxena (1985) found larger scrotal circumference in Nigerians than Europeans (212.6 mm vs 195.1 mm or 8.37 in. vs 7.68 in.)
Strangely, by 2000, Rushton seems to have grown somewhat amnesiac [1]:
Race differences in testicle size have also been measured (Asians = 9 grams, Europeans = 21 g). This is not just because Europeans have a slightly larger body size. The difference is too large. A 1989 article in Nature, the leading British science magazine, said that the difference in testicle size could mean that Whites make two times as many sperm per day as do Orientals. So far, we have no information on the relative size of Blacks.
Rushton also conveniently ignores "A French Army Surgeon" where the latter's claim fails to line up with the former's theory:
In no branch of the human race are the male organs more developed than in the African Negro. I am speaking of the penis only and not of the testicles, which are often smaller than those of the majority of Europeans.

Vaginal size

Rushton claims (apparently again relying on "A French Army Surgeon"):
Women were proportionate to men, with Orientals having smaller vaginas and blacks larger ones, relative to Caucasians.
Modern studies fail to bear out this claim, which tends to further reduce the credibility of Rushton's 19th-century source. One study using MRI finds "[r]ace was not associated with any differences in measurements of vaginal dimensions" [5]. A different study finds [6]:
posterior cast length is significantly longer, anterior cast length is significantly shorter and cast width is significantly larger in Hispanics than in the other two groups and (2) the Caucasian introitus is significantly greater than that of the Afro-American subject.
Nor do the "Afro-American" subjects have deeper vaginas: "[a]verage rod lengths for Caucasians and Afro-Americans were 11.51 and 11.18 cm [. . .] significantly different as measured by t test" [6].

References

[1] Race, Evolution, and Behavior 2nd Special Abridged Edition (pdf)

[2] Rushton, J.P. & Bogaert, A.F. (1987) Race differences in sexual behavior: Testing an evolutionary hypothesis. Journal of Research in Personality 21(4): pp. 536-7 (link)

[3] Orakwe JC et al. Can physique and gluteal size predict penile length in adult Nigerian men? West Afr J Med. 2006 Jul-Sep;25(3):223-5. (link)

[4] Ajmani ML et al. Anthropometric study of male external genitalia of 320 healthy Nigerian adults. Anthropol Anz. 1985 Jun;43(2):179-86. (link)

[5] Barnhart KT et al. Baseline dimensions of the human vagina. Hum Reprod. 2006 Jun;21(6):1618-22. Epub 2006 Feb 14. (link)

[6] Pendergrass PB et al. Comparison of vaginal shapes in Afro-American, caucasian and hispanic women as seen with vinyl polysiloxane casting. Gynecol Obstet Invest. 2000;50(1):54-9. (link)

[7] WHO Global Programme on AIDS. Specification and Guidelines for Condom Procurement. Appendix VII, Regional or Ethnic Differences in Erect Penis Size. Geneva: WHO, 1995. (pdf)

Racial differences in vaginal dimensions: strike one more against Rushton

J.P. Rushton in Race, Evolution, Behavior (pdf) claims black > white > Asian. What do we actually see?
Gynecol Obstet Invest 2000;50:54–59

Comparison of Vaginal Shapes in Afro-American, Caucasian and Hispanic Women as Seen with Vinyl Polysiloxane Casting

Paula B. Pendergrass Cornelia A. Reeves Meyer W. Belovicz Darron J. Molter Janet H. White

Abstract

Full vinyl polysiloxane casts of the vagina were obtained from 23 Afro-American, 39 Caucasian and 15 Hispanic women in lying, sitting and standing positions. A new shape, the pumpkin seed, was found in 40% of Afro-American women, but not in Caucasians or Hispanics. Analyses of cast and introital measurements revealed: (1) posterior cast length is significantly longer, anterior cast length is significantly shorter and cast width is significantly larger in Hispanics than in the other two groups and (2) the Caucasian introitus is significantly greater than that of the Afro-American subject.

[. . .]

In addition to the three molds, vaginal length and introital distensibility were obtained. With the subject in the supine position, length was taken by having the subject insert a 7-inch polished acrylic rod as far back into her vagina as possible without causing discomfort; introital distensibility was determined by having the subject insert a lubricated 125-ml polypropylene Erlenmeyer flask as far back as possible into her vagina without causing discomfort. The circumference at the point of entry was marked and measured, and a diameter was calculated.

[. . .]

Comparisons of the length of anterior and posterior cast walls as measured with calipers for all three study groups are given in table 2. For the posterior measurements, Hispanics showed a much narrower range than either Afro-Americans or Caucasians, and, importantly, they exhibited no posterior lengths less than 8 cm. Consequently the mean for Hispanic casts was significantly greater (p = 0.01). The mean anterior length for Hispanics was also significantly different (p = 0.01) but was shorter than those of the Afro-Americans and Caucasians. Consequently, the overall picture of the Hispanic cast is one that is relatively short along the anterior wall, but considerably longer along the posterior wall. The longer posterior measurements are reflected in deeper posterior fornices among the Hispanic subjects which, interestingly, all showed a full cervical imprint in the cast; this suggests that the cervix in Hispanics consistently lies in a deeper position within the vaginal vault.

Comparisons of the length of anterior and posterior cast walls as measured with strings for all three study groups are shown in table 3. These measurements directly reflect the caliper measurements. Hispanic casts are significantly longer posteriorly (p = 0.01) and shorter anteriorly (p = 0.01), with anterior lengths being shifted downward 1–1.5 cm.

Maximum widths (side-to-side) and depths (anteriorposterior) are given in table 4. Hispanic casts are significantly wider than either Afro-American or Caucasian casts (p = 0.01), with the mean being over 2 cm greater than Caucasians, and over 1 cm greater than Afro-Americans. Also, the range of widths is noticeably narrower among Hispanics indicating a more homogeneous group.

The mean depth is somewhat greater among Hispanics but is not significantly different from that of Afro-Americans and Caucasians. The variability among Hispanics is smaller with a narrower range and a smaller standard deviation.

Average rod lengths for Caucasians and Afro-Americans were 11.51 and 11.18 cm, respectively, and introital diameters were 4.66 and 3.14 cm, respectively. Both measurements were significantly different as measured by t test (table 5). Because rod and introital measurements were obtained from only 5 Hispanic subjects, no statistical comparisons can be made. Hispanic rod lengths ranged from 8.2 to 12.5 cm, and the introital measurements ranged from 1.9 to 3.2 cm.

A summary of t tests for comparison of Caucasian, Afro-American and Hispanic subjects is presented in table 5. These results show statistically significant differences among the three groups in the following areas: (1) the posterior cast length as measured with both calipers and strings is significantly longer for Hispanics than for Caucasians and Afro-Americans; (2) the anterior cast length as measured with both calipers and strings is significantly shorter for Hispanics than for Caucasians and Afro-Americans; (3) the width of casts in the lying position is significantly greater for Hispanics than for Caucasians and Afro-Americans; (4) the Caucasian introitus is significantly greater than that of the Afro-American. From this we conclude that there are differing distributions of shapes and much greater homogeneity among Hispanics than among Afro-Americans or Caucasians.

Trivial, perhaps, but these things add up. Racial differences exist, but--contrary to the impression one might get reading REB--they don't always neatly align with Rushton's "r-K" framework. Much of his work has value, but Rushton is far from infallible.

Previously, I've taken issue with some of Rushton's claims concerning testosterone (low in sub-Saharan Africans compared to Westerners; minimal black-white differences in America; hardly a good candidate to explain black social pathology), fundamental vocal frequency, penis size (what evidence exists suggests minimal black-white differences), and testis mass (greater in whites compared to Asians and blacks, according to the available autopsy studies).

Digit ratio doesn't follow Rushton's rule

Chris Brand reviews a new book:
BOOK REVIEW of Manning, J. ( 2008), The Finger Book: Sex, Behaviour and Disease Revealed in the Fingers. Pp. 170 + xiii. London : Faber & Faber.

Reviewed by CHRIS BRAND. Available at Amazon

This book, by a British evolutionary psychologist at the University of Central Lancashire (formerly Preston Polytechnic), argues that there are links between ring-finger length (RFL), testosteronization in the womb, masculinity, personality, polygamy and race. It gets off to a slow start, but there is drama enough by the finish.

The ring finger is hairier in males than other digits, perhaps reflecting its being more under the influence of the sex hormone testosterone and its being assigned for the wedding ring. In any case, RFL, relative to index-finger length (the normal ratio in Whites is approximately 1:1), is greater in males and also in top athletes and sportsmen, autists, attention-deficit children and butch lesbians; and it correlates negatively with psychologists’ measures of agreeability, gentleness and femininity. Thus goes the first 90% of Manning’s (rather repetitive) book.

Of course there are some problems. It is not obvious why RFL should be measured from the point of the finger’s lowest skin crease with the palm rather than from the knuckle. The inter-observer reliability for RFL is not stated or even considered. There seems no special reason why testosterone should especially affect the growth of the ring finger. All the associations with RFL mentioned above are pretty slight (Manning does not give correlations but his occasional scattergrams indicate effect sizes of around .25). And other efforts to argue for links to RFL don’t really work at all: the promised link to left-handedness doesn’t materialize (though Manning might have tried ‘mixed-handedness’, often associated with mild personality difficulties), and the proposed link to schizophrenia is a mess (with too many complications arising from ‘testosterone inhibitors’ and genes determining the uptake of said inhibitors). But Manning has had no difficulty finding academic collaborators to undertake empirical work with him over the 15 years since the RFL links were first advertised to psychologists by Hans Eysenck’s ‘first lieutenant,’ Glenn Wilson; and there clearly is a case to answer.

[. . .]

All but the most piously anti-racist readers who have got this far with the present review will know of the claims of Philippe Rushton, Richard Lynn and the London School that the main established psychological gradation between the human races is that running from East Asians through Caucasians to Negroes and characterized primarily as one of inherited general intelligence (cf. IQ) though also being linked to law-abidingness and sexual restraint. Well, Manning likewise has a broad dimensional claim to outline – set out finally in a graph on the penultimate page of his book.

Though not especially motivated to study race – and thus apparently never having read any London School work – the empirical studies which he has found or organized have yielded a clear and interesting picture, bringing together Blacks and East Asians (Zulus, Jamaicans, Chinese and Japanese) as high-RFL and distinguishing them from the typically low-RFL Europeans (Polish, Spanish, English and Hungarian – with Germans and Gypsies scoring a little higher, intermediate with Chinese levels). For just what this means (if it replicates), Manning’s readers are left to refer to the book’s earlier claims. But the finding of a marked and allegedly important similarity between Blacks and East Asians will amaze many – and not just Rushton and Lynn. This is particularly because, having started his book by tending to play up the advantages of early testosterone (good for the heart, supposedly), Manning ends by making the human shift to right-handedness (long called ‘the right-shift factor’ by the equally unmentioned Marian Annette) fundamental to language and civilization as we know it and attributing it to foetal oestrogen and thus linking it to short RFL.

I've previously demonstrated black-white differences in circulating testosterone are minimal in adult males.

It's certainly conceivable there are racial differences in pre-natal androgen exposure, though--considering the major races are known to vary in any number of anthropometic indices not putatively linked to androgen exposure--it's not clear to me how meaningful unadjusted cross-racial comparisons of digit ratio are. Regardless, digit ratio can't be dragged out by those trying to shore up "Rushton's rule" with respect to androgenization.