Book review of “Breeding between the Lines” by Alon Ziv

This is a book review of “Breeding between the lines: Why interracial people are healthier and more attractive,” by Alon Ziv, 184 pp., Barricade Books, 2006, ISBN: 1569803064. My preliminary impression that the book most likely doesn’t have decent data in it is confirmed.

The book is written for a lay readership, and with the main text occupying about 160 pages, it can be read within a few hours.

Sloppy work: errors and omissions

Alon Ziv appears to have been working on the main idea of the book for a couple of years, but his book is full of sloppiness and naïve arguments, which is curious given the apparent time he has spent perusing the literature and also that he appears to have an adequate background in the biological sciences. I will provide some illustrative examples.

Ziv provides a primer on evolution that includes statements such as:

• Asexual people are like slow Cheetahs – they die out.
• We have evolved to avoid incest; incestuous individuals had inferior offspring and died out.

Well, asexual people die out every generation, but nothing seems to prevent some from being born every generation. For instance, in a national probability British sample of over 18,000 people, roughly 1% of people assessed reported that they were asexual, i.e., had no sexual interest in either men or women[1].

Similarly, whereas most people abhor incest, let alone indulge in it, some people continue to harbor incestuous fantasies and engage in incestuous sex[2-4].

There are numerous examples of evolutionary maladaptive characteristics that persist in small numbers in the population, but Ziv ignores this.

Ziv argues that our bodies are designed to have bilateral symmetry, i.e., we are designed to be perfectly symmetrical. This is incorrect. There is both a random and a non-random component to bilateral asymmetry, and it is the random component that is not part of biological design. The magnitude and direction (left or right side greater) of the random component fluctuates between individuals and hence this component is designated as fluctuating asymmetry. Throughout the book, whenever Ziv cites the literature on symmetry and especially when he extols the virtue of greater bilateral symmetry as in corresponding to better health and greater attractiveness, he is actually referring to the literature on fluctuating asymmetry, and the correct statement is that a lower level of fluctuating asymmetry, rather than greater symmetry, is correlated with somewhat better health and greater attractiveness. For instance, fluctuating asymmetry rather than directional asymmetry is a correlate of attractiveness of faces[5].

Ziv claims that heterozygosity for sickle cell anemia makes the carrier resistant to malaria, but this is not true; what happens is that the severity of malarial infection is reduced in these individuals, which increases the probability of survival should an infection occur.

Ziv acknowledges that races exist, but then cites pathetic sources to support this assertion: the approval of the drug BiDil for blacks by the FDA and a comment on Cavalli-Sforza’s book by Steve Sailer! No serious scientist, aware of the nature of race denial, would cite such poor sources. One needs to cite molecular[6-8] and skeletal evidence[9, 10] in conjunction with standard phylogeographic criteria for race assignment in order to make the case for races among humans. Ziv even says that “since race is really a continuum, there is no ideal way to define or document it.” Well, there is clinal variation with respect to individual characteristics, even a group of neutral DNA markers, and a race denial argument specifically denies racial reality because of human clinal variation[11], but race is characterized by a cluster of variables, and the existence of racial clusters has been shown in spite of clinal variation of DNA markers[6].

Ziv reports that in spite of changing fashions, the optimal waist-to-hip ratio of 0.7 in women, according to the research of D. Singh, has not changed; it has remained in the 0.68-0.72 range for Miss Americas and Playboy centerfolds. Well, waist-to-hip ratio in Miss Americas and Playboy centerfolds has increased from the mid- to late-20th century[12]; these women have become more masculine. During the early years of Playboy, waist-to-hip ratios were less than 0.7, on average. Additionally, there is nothing universal about the 0.7 figure: men in some black[13] and Native American[14, 15] populations prefer women with higher front-on waist-to-hip ratios than white men.

Ziv claims that more lopsided individuals (less symmetrical) are more likely to respond aggressively when provoked, but it is not difficult to come up with some papers where more symmetrical people turned out to be more physically aggressive[16, 17]. The latter is merely one example of Ziv omitting the literature that does not support his case.

Ziv is so sold onto the notion of hybrid vigor that he tries to see some in even ill-fated interspecies crosses. For instance, Ziv writes that a mule (horse mother, donkey father) may display some hybrid vigor because it has more stamina and more load-carrying capacity than horses! Hybrid vigor is inferred when the offspring are overall better than their parents, but mules are sterile. Ziv also cites the example of attempts to breed sheep and goats, which are typically unsuccessful, but he describes an example of a success that may have displayed some hybrid vigor as it grew faster than regular sheep or goat offspring, and was so oversexed that it frequently attempted to mount both sheep and goats. The poor animal had to be castrated to reign in his amorous pursuits, but faster growth and the oversexed nature could easily be a manifestation of abnormal development rather than hybrid vigor.

Ziv mentions inbreeding depression and hybrid vigor but fails to mention outbreeding depression. For the uninitiated, depression here refers to the offspring being overall worse than the parents and vigor refers to the offspring being overall better than the parents. There are plenty of examples of race mixing leading to outbreeding depression in various species[18-31].

Several claims in the book are not cited. For instance, Ziv reports a study where underweight newborn babies were more likely to be homozygous (less genetically diverse), but does not cite the reference. Given the small size of the book, it would not have hurt Ziv to add twenty additional pages of references.

Ziv reports that studies show that whites are the least likely to accept intermarriage, which is far from true. Jews, Muslims, Hindus and many other groups are easily much less accepting of intermarriage than whites are. Ben Tillman has previously brought to my attention that the oft-quoted 50% outmarriage rate for American Jews is an exaggeration, and it has been pointed out that even if this figure were taken at face value, it indicates a notable resistance to outmarriage among Jews given their small numbers in the U.S.; see this comment for details. Additionally, when Jews outmarry, most of the time it is with whites rather than with blacks or East Asians. Israel does not allow marriage between Jews and non-Jews, just as Muslims are forbidden to marry non-Muslims. On a related note, Ziv cites anti-miscegenation laws in some U.S. states decades ago, but fails to mention, let alone condemn Israel’s existing laws prohibiting marriage between Jews and non-Jews. In multiracial societies with a significant white presence, whites tend to disproportionately occupy the upper classes, and whereas the appreciation of the physical appearance of a number of populations is mostly limited to within the respective populations, white looks are appreciated by a substantial number of people in most populations. In other words, being white is disproportionately associated with higher status. Therefore, one observes that among non-white groups that generally oppose intermarriage, when they accept intermarriage, it is usually if the spouse is white or a higher status race, but they display marked animosity if the spouse is an other-race non-white of lower racial status. On the other hand, when whites intermarry, they almost always marry someone coming from a lower-status race. Non-blacks generally perceive blacks to be the lowest status race in terms of both looks and socioeconomic status, i.e., the willingness of a large number of blacks to outmarry should not be surprising, and it is obvious that one cannot argue for a naturally high willingness to outmarry among blacks given that there are not a whole lot of non-black races of lower socioeconomic and looks status than blacks. When black women object to black men marrying non-blacks, it is has less to do with objection to outmarriage per se than with the fact that so many black men are in prison or jobless/criminal that their already-low partner prospects are reduced by outmarrying black men. In short, Ziv is grossly mistaken about whites being the least likely to accept intermarriage.

Other problems with Ziv’s book should be seen in light of his main thesis.

Main thesis

Ziv’s main thesis is simple. He argues that more symmetrical people are more attractive, healthier and more heterozygous (more genetically diverse). He then points out that since race mixing increases heterozygosity, it leads to more attractive and healthier people. Let us examine this argument.

Hybrid vigor

Ziv addresses an example of hybrid vigor involving mixing some races of corn, and notes that “the disadvantage of hybridization is that you have to re-create the hybrid seed every generation.” Why doesn’t Ziv elaborate on this? Here is why. Let there be a gene that exists in two versions, A and a; each individual has two copies of this gene. Therefore, an individual could be AA, aa or Aa. Let the beneficial genotype be Aa. If one crosses AA with aa, all first generation hybrids will be Aa. If the first generation hybrids breed among themselves at random, the ratio AA:Aa:aa = 1:2:1, i.e., the desired genotype is present among only half the second generation hybrids. It is for this reason that corn farmers would maintain the original parental stocks and cross them to obtain hybrid vigor, but not allow the hybrids to reproduce among themselves. Obviously, among humans this is not applicable. The example considered here is a single-gene case, but if hybrid vigor is applicable to interracial breeding among humans with respect to multiple genes, then it should be clear that it will be drastically reduced among second and subsequent generation hybrids.

Ziv offers the following examples of hybrid vigor among humans.

• He cites the tale of mutineers on the HMS Bounty (1789) settling on Pitcairn Island and mating with the local women. The half British-half Tahitian children, according to Ziv, grew up to be 2.5 inches taller than the British and the Tahitians. It is difficult to determine the reliability of this report.
• Ziv reports a study, where Khasi girls in northeast India (basically East Asian types) were shorter than girls born to Khasi women that had mated with immigrant Muslim men (less Asiatic)[32], as an example of hybrid vigor, but this study did not assess the height of the parents and reported that the neighboring Muslims were a taller people. Therefore, how can one be sure that this is an example of hybrid vigor? If Khasi women breed with taller men, they are bound to produce taller children.
• Ziv cites an UCLA study by Jay Phelan that showed mixed-race individuals to be more symmetrical (less fluctuating asymmetry) than individuals that were classified into only one of the following groups: white, East Asian, black, Native American or Hispanic (total sample size was 99). This find is reportedly highly significant; the probability that it is a chance find being less than 0.007%. The 25 least symmetrical individuals were uniracial whereas 7 of the 8 most symmetrical individuals were multiracial/mixed race. The participants also apparently had their pictures taken and evaluated for physical attractiveness, and the mixed-race individuals were rated as better looking. Curiously, this study does not appear to have been published, though it was featured in a UCLA report dating to November 04, 2002. Ziv’s citation mentions personal communication. Four years is more than enough time for research to be published. Has this study not been published because of its poor quality? Jay Phelan is co-author of the book “Mean Genes,” and he also wrote the forward to Ziv’s book. Phelan harbors the same idea as Ziv as far as the supposed benefits of race mixing go.

Ziv provides supportive evidence by citing examples of hybrid vigor resulting from crossing inbred strains of animals such as mice, and also cites studies from Swiss[33] and Polish[34] villages where children born of parents from different villages were taller, heavier and larger-chested compared to children born of parents from the same village, though the Swiss study actually compared the Swiss sample with their relatives that had outmarried in California.

The Swiss and polish studies are not about hybrid vigor, but Ziv extrapolates from these studies that the outcome of race mixing will be even better, assuming that the higher the heterozygosity, the better it is, apparently because more diverse genes mean more diverse gene products, which should cover an individual over a broader range of the environment. The latter reasoning appears sound, but then why is outbreeding depression observed in a number of cases? Has Ziv never heard of co-adapted gene complexes, which are disrupted by hybridization? Has Ziv never heard of the concept of genetic architecture in cardiovascular disease, whereby it is not always an allele (one of several versions of a gene) per se that is associated with disease, but the allele in a given environmental and genetic background[35-37]? For instance, a haplotype that slightly increases the odds of a heart attack among American whites is found in smaller numbers among American blacks, who have gotten it from whites, but it confers a 3-fold larger risk in black Americans[38]. Similarly, an allele that confers protection against diabetes among whites does no such thing among south Asians[39].

The paper on the Khasi, which Ziv has presumably read given that he cited it, mentions an Israeli study that attempted to infer the effect of intermarriage, between Jewish groups that had immigrated to Israel from different parts of the world, on the longitudinal growth of children. Five mixed groups were analyzed: two of these were similar to a parental group, one showed some evidence for enhanced growth, and two groups showed some detrimental effects of mixing[40]. I suspect that the null and detrimental finds in this study prompted Ziv to not cite it.

It should be noted that rats and mice are commonly used lab animals, and it is necessary that the differences among the experimental and control groups be attributed to the experimental protocol rather than genetic variation between the groups. Therefore, rats/mice used in a typical experiment come from a highly inbred line, and it should not be surprising that crossing two highly inbred and closely related races results in reduced overall fluctuating asymmetry, but human races, especially those existing in large numbers, are nowhere as inbred as lab rats/mice are. In a study were wild mice were made to inbreed, the overall fluctuating asymmetry of the inbred mice was not greater than that of the outbred group, even though these two groups had different fitness under seminatural conditions[41], but Ziv has not mentioned this study at all. This study is merely one of several that have shown fluctuating asymmetry to be a poor indicator of developmental stability.

Some studies have shown little to no relationship between fluctuating asymmetry and heterozygoisty[42-44], whereas some have even shown fluctuating asymmetry to increase beyond a certain level of heterozygosity[45, 46], i.e., outbreeding depression. In a meta-analysis of 118 datasets published in 41 studies[47], the effect size correlation between fluctuating asymmetry and heterozygoisty was r = -0.09 (SE=0.03), a low effect size correlation, but the interesting data is in the following figure, namely a non-significant trend toward a weak positive effect size correlation in endotherms (animals that maintain a constant internal body temperature), i.e., a non-significant trend for greater heterozygosity in endotherms to correspond to somewhat less symmetrical individuals. To interpret effect size correlation (ES): small ES (less than 0.15), medium/moderate ES (0.15 < ES < 0.33), large ES (greater than 0.33).

In this meta-analysis, heterozygoisty accounted for one percent of the variation in developmental stability assessed via how symmetrical the individuals were, and even for ectotherms the variance accounted for was only 2% (r=−0.23 ± 0.09)[47]. If Ziv did proper research, he could not possibly have missed this meta-analysis, but he apparently does not cite this because he wants to convey that more heterozygosity equals better symmetry, which translates to more attractiveness and better health, all of which mean that miscegenation for the purposes of increasing heterozygoisty can only be positive with respect to physical and mental development.

Mating preferences

Ziv notes that evolution should shape people to breed in ways that are the most beneficial, yet laments that people generally tend to breed within their races, which is apparently not the best strategy as far as the benefits of heterozygoisty go: more attractive and healthier people. One of the reasons for people mostly seeking partners within their race is that people seek partners in accordance with an internal blueprint, but the good news for Ziv is that this internal blue print can be altered with sufficient exposure to people of other races. He cites the example of snow geese: the white ones breed with whites and the blue ones breed with other blue geese. However, when white geese are raised by blue geese, they prefer blue geese and blue geese raised by white geese prefer white geese. Snow geese of any variety show no preference for white or blue geese if they are exposed to both since birth. Therefore, Ziv extrapolates that humans exposed to multiple races since birth, which will be a reality with mass immigration of multiple races into the West, will not show a specific preference for their own race. This is another non sequitur. More complex human brains are not as susceptible to imprinting as bid brains are. In multiracial societies, non-whites tend to have a preference for facial features closer to that of the white average, but it is uncommon for whites to prefer non-white facial features.

Health

Ziv offers no direct evidence for improved health among mixed-race individuals, and ignores evidence for an across-the-board increase in health problems among mixed-race individuals in a large, representative sample of U.S. adolescents[48]. I have previously addressed this study by J. Richard Udry; the most likely reason for the worsened health of the mixed-race individuals is increased odds of the disruption of the autonomic nervous system, resulting from race mixing.

A study involving undergraduate students at San Francisco State University and the University of Hawaii at Hilo revealed that mixed-race individuals (basically white-Asian mixes) had worse health than whites or Asians[49]; read the paper.

A newer study that assessed substance use and violent behaviors among 2,082 students in Seattle public middle schools has reported mixed-race individuals being worse on these counts, after controlling for differences in socioeconomic status[50]; read the paper. This study also assessed ethnic identity and perceived discrimination to evaluate the extent to which they were related to the problem behaviors. However, a positive ethnic identity was protective on some counts only, and was associated with an increased likelihood of the participants having ever threatened to beat someone up. Perceived discrimination was associated with increased likelihood of problem behaviors on some counts only, but it cannot be assumed that discriminatory experiences were responsible for the problem behaviors since problematic behaviors on the part of individuals would invite discrimination.

Clinical samples have shown higher rates of mental and behavioral problems among mixed-race individuals[51, 52]. There have been few studies showing mixed-race individuals to be comparable to single-race individuals: a study from Hawaii reported no differences with respect to personality variables[53] and another study reported no differences with respect to quality of parent and adolescent relationship[54]. A few years before Udry[48] published the health data from the National Longitudinal Study of Adolescent Health (Add Health), Cooney and Radina[55] published some of this data, and reported multiracial individuals to be worse than uniracial individuals on less than half the school performance, behavioral and psychological dimensions assessed, but a more thorough analysis by Udry shows multiracial individuals to be worse on most measures, including health. Except for the Seattle middle schools study[50], which was likely published after Ziv submitted his final manuscript for publication, Ziv couldn’t possibly have failed to come across the others showing worse health among mixed-race individuals, but he pretends as if these studies don’t exist.

India is a cesspool of race mixing, but East Indians have some of the highest if not the highest prevalence of cardiovascular disease, the metabolic syndrome, diabetes, insulin resistance, hyperinsulinemia, central obesity, dyslipidemias such as lower high-density lipoprotein or increased low density lipoprotein or higher triglyceride levels, increased thrombotic tendency as in increased plasminogen activator inhibitor-1 and decreased tissue plasminogen activator levels, and low birth weights[56-63], in addition to a weak musculo-skeletal build[64-67]. It is remarkable how often I have seen slenderly built south Asian males with a tendency to pack on excess body fat, especially in the abdominal region. The prevalence of cardiovascular disease among mixed-race groups such as south Asians, blacks and Hispanics in the U.S. is 2- to 3-fold higher compared to that among whites[68]. Whereas a number of the papers cited within this paragraph have been published in 2006, they are documenting data that have been well-known for years. Why has Ziv not cited such data?

Athleticism/Sporting ability

Ziv cites a study about more heterozygous oysters being better able to utilize oxygen under stress, and then notes that the implications for human athletics are staggering! Talk about non sequiturs! In a human study, overall body symmetry was unrelated to lung capacity and maximal oxygen utilization[69], i.e., the more symmetrical individuals, which Ziv would describe as more heterozygous, were not better off with respect to the physiological capacities addressed. Another study reported that elite athletes were not more symmetrical than sub-elite athletes[70]. Now, there are studies showing skilled athletes being more symmetrical than non-athletes (see review in Tomkinson et al.[70]), but the relationship is weak, and by not citing negative finds, Ziv is trying to convey that the relationship is so strong that interracial mating to increase heterozygosity is highly recommended.

The only example of a mixed race great athlete that Ziv cites is Tiger Woods, but if I recall correctly, then Tiger Woods had severe myopia, which had to be surgically corrected. If my recollection is correct, then without modern technology, if Tiger Woods had to live as a hunter-gatherer, he would quickly become prey, and he would also be a pretty useless fighter.

In the 1970s, there were several American blacks playing the PGA tour, but in spite of an increase in the popularity of golf and the greater participation of American blacks, currently, Tiger Woods is the only part-black person playing the PGA tour; see more.

There have been some great mixed-race athletes, e.g., Jim Thorpe and Daley Thompson, but the Decathlon is mostly dominated by whites, just as most Olympic sports are. In addressing race, Ziv addresses whether some races are better at some things than others, and says that this is an issue that he doesn’t want to focus on, but he points the interested reader to Jon Entine’s book, “Taboo: Why black athletes dominate sports and why we are afraid to talk about it.” This book alleges the racial athletic superiority of blacks, but Entine is as clueless as Steve Sailer on this topic. Blacks only dominate a few sports. West African blacks do not dominate sports such as weightlifting, powerlifting, martial arts, strong man competitions or freestyle fighting, where their alleged superior speed and strength should give them an advantage. Presently, all four heavyweight boxing titles are held by whites. Castefootball.us also features plenty of evidence about anti-white discrimination in American team sports such as football and basketball, showing that the heavy black overrepresentation in these sports is not entirely merit-based. All-white teams from Europe have been learning the game of basketball, and in recent years have defeated all-black teams from the U.S. on several occasions. Things are bound to get more interesting.

When it comes to thousands of years of race mixing between multiple races, it would be hard to beat India, yet East Indians are undoubtedly among the worst if not the worst athletes in the world.

Attractiveness

In a meta-analysis of correlates of facial beauty by Gillian Rhodes[71], the effect size correlations (ES) were: average facial features (0.52 ± 0.41; 95% CI = 0.42-0.61; weighted ES = 0.54), symmetry (0.25 ± 0.34; 95% CI = 0.16-0.33; weighted ES = 0.23) and femininity (0.64 ± 0.39; 95% CI = 0.51-0.74; weighted ES = 0.61). The data are reported as effect size correlation (ES) ± standard deviation; the interval that one would be 95% confident the actual ES lies in the general population; ES weighted by the number of faces examined.

Ziv’s argument that mixed-race individuals are more attractive is based on the assumption that greater heterozygosity equals more symmetry, which equals greater attractiveness, but there are at least two much more powerful correlates of facial beauty that Ziv ignores.

The only study that Ziv cites in favor of mixed-race individuals being more symmetrical is Jay Phelan’s study, which remains unpublished four years after its completion. We have already seen that the relationship between heterozygoisty and symmetry (thereby developmental stability) is very weak.

What about average facial features? As I mentioned previously, Ziv should read about craniofacial morphology in mixed-race individuals, white-Native American mixes to be more precise, and note that canonical variates analysis revealed a canonical root, explaining 36% of the variance, that made the mestizos deviate from shape variables in between whites and Native Americans[72].  52% of the 52 shape variables deviated from the mathematical average shape of the parent races, and here is the money shot[72]:

Finally, it is interesting that the distances that could not be assigned to a particular developmental pattern appeared to introduce ‘‘noise’’ and blur the effects of cranial integration.

The developmental patterns talked about above are mathematical averaging based upon the expectation from quantitative genetics, i.e., additive genetic variation, and morphological integration of different parts of the skull, whereby different parts of the skull effectively behave like a single unit, i.e., a change in one part corresponds to changes in other associated parts.  Note the term “interesting;” this term is an euphemism for some loss of morphological integration in the skull resulting from race mixing, i.e., some solid evidence that yes indeed, races exist among humans, and also that humans races—at least the two considered and by extrapolating from genetic distances and skull shape comparisons, any combination of races—are sufficiently distant so as to result in disruptions of co-adapted gene complexes and subsequent increased odds of anomalous outcomes in mixed offspring, which is confirmed by the health data addressed above.

Morphological integration is an important concept. Whereas one may not appreciate the facial features of another race, one will be able to pick out the better looking among another race, and these better looking people will have some kind of harmony between various parts of their face, but this harmony is more likely to be lost as a result of race mixing compared to same-race breeding. For instance, I previously commented on the malformed appearance of the deranged model Heidi Klum’s mulatto baby.

Some would point out that neonates are not exactly cute, but Henry Guenther Ademola Dashtu Samuel, the son of Heidi Klum and Seal, clearly looks like something is wrong with him. The malformed mulatto neonate has grown into a retarded-looking malformed toddler; contrast his features with the beauty of the white child Heidi Klum had previously. I have seen black babies that are a lot better looking.

Actual shape variables are important, too. From the perspective of whites, non-white admixture can only diminish the attractiveness of the descendents of whites: make noses broader, make the middle portion of the face flatter (absorption of East Asians, Native Americans, Eskimo-Siberians, khoi-San people, some central African populations), make faces broader (absorption of East Asians, most black African populations, Native Americans, Eskimo-Siberians), make jaws more protruding (especially if blacks, Melanesians and Australian aborigines are involved), make faces larger (absorption of most non-white populations), decrease height (absorption of many non-white populations, especially for northern Europeans), make limbs smaller relative to height (absorption of East Asians, Eskimo-Siberians, Native Americans), increase the frequency of hooked noses (absorption of Middle Eastern populations such as Jews), weaken musculo-skeletal build (absorption of non-whites in general except West Africans and Polynesians), etc.

In addition, non-whites possess more primitive facial features, and some of them disproportionately persist when they mate with whites. For instance, a study from Hawaii reported the persistence of the broad face/massive cheekbones of East Asians among Asian-white hybrids[73]. In addition, flared nostrils, broader noses and more protruding jaws also tend to persist.

What about femininity? No citations are needed for the less feminine physiques of East Asian and physically similar women. Black women, in spite of their larger breasts and more protrusive buttocks, are unable to look as feminine as white women as a result of their greater muscularity, higher front-on waist-to-hip ratios and facial features. White women look more feminine, and I would refer the reader to a previous, currently active, thread on Nordic beauty, where I have put up numerous comparisons; I still have to respond to several comments there, and my replies will feature more comparisons, but posting this review first is more important. Rhodes’ meta-analysis makes it clear that femininity is a much more powerful correlate of beauty in women compared to symmetry, yet Ziv ignores femininity.

I expected to see Ziv cite Gillian Rhodes’ study about the greater rated attractiveness and perceived health of Asian-white hybrids[74], but Ziv hasn’t cited it, and it may have come out too late for Ziv to cite it. I have previously critiqued this study. In short, the whites in this study were unattractive, and the assumption of the authors that race mixing will average the facial features of the parents is not true[72].

Intelligence

Ziv cites a study from Hawaii where white-Japanese hybrid children outperformed white or Japanese children on 13 of 15 cognitive tests (e.g., 0.30 S.D. on a version of the Raven’s progressive matrices and 0.22 S.D. on the PMA Vocabulary Test), in spite of no significant socioeconomic differences between the groups[75]. The confound here is assortative mating for IQ, i.e., it cannot be assumed that the whites and Japanese that bred together came from a random sample of their respective racial groups. Udry studied a large, random population of U.S. adolescents, but as the following table from his paper shows[48], the GPA (grade point average) and verbal IQ of the mixed-race individuals were in between those of the individuals belonging to their parental racial groups, i.e., no hybrid vigor was observed.

One possible example of hybrid vigor with respect to IQ, from the perspective of black Africans, suggested by Arthur Jensen, is that American blacks have an IQ of 85, 15 points or 1 S.D. higher than that of their black African counterparts, even though white admixture among them averages 10-20%. However, if we assume that the black African average IQ would be a few points higher if malnutrition/undernutrition were eliminated, then given that there is a positive correlation between health and IQ, it is reasonable to suppose that Africans bound for slavery in the U.S. were among the healthier ones, and given the harsh conditions of transport, healthier still individuals made it to the U.S. Therefore, the IQ potential of the arrivals could be around 80, and white admixture may only have raised IQ by 5 points or so instead of 15 points, which would not necessitate positing hybrid vigor from the perspective of black Africans, but the validity of this proposal is unclear, and in any case, at present, the 85 IQ of American blacks is not proof of hybrid vigor from the perspective of black Africans.

Ziv cites a paper by Mingroni[76], which proposes heterosis as possibly partially accounting for the Lynn-Flynn effect, i.e., the secular worldwide rise in IQ scores documented in the 20th century. Mingroni’s argument is reasonable. Throughout the period of this secular trend, the heritability of IQ has remained very high, which is not easy to account for if one assumes that environmental factors are involved, and Mingroni cites papers that have critiqued the implausibility of a model proposed by Dickens and Flynn that has argued for a large effect of the environment on IQ. However, the heterosis proposed by Mingroni postulates increased mixing of people from neighboring villages, which is not hybridization (mixing of different breeds), and it does not follow, as Ziv assumes, that the greater the outbreeding, the better it will be. In addition, data from Spain show that the bulk of the Lynn-Flynn effect over a 30-year period was accounted for by gains mostly in the lower half of the bell curve, with very little change in the 99th percentile and spectacular gains in the first percentile[77]; see the gain in raw scores. Therefore, improved nutrition is certainly accounting for a good deal of the Lynn-Flynn effect. Mingroni also cites secular increases in high-heritability factors such as height, head circumference, myopia, autism, asthma and possibly ADHD. If greater outbreeding, though still mostly within racial groups, is partly responsible for the Lynn-Flynn effect and also increases in abnormalities such as myopia and asthma, then general heterosis is not implicated.

The three highest IQ groups are: U.S./U.K. Ashkenazim diaspora (IQ = 110[78, 79]), northeast Asians (IQ = 105) and northern Europeans (IQ = 100). Northeast Asians and northern Europeans have very little other-race admixture. Jews are more heterogeneous, but the most plausible explanation for the Ashkenazim IQ advantage is that under selection pressures for higher IQ, a high level of inbreeding among them accumulated several deleterious alleles that have the side effect of increasing IQ[80]. Therefore, the brightest groups certainly didn’t get that way by large-scale outbreeding. In addition, notwithstanding the northeast Asian IQ advantage over northern Europeans, especially with respect to math ability, whites are heavily overrepresented, in spite of their smaller numbers, among Nobel Prize winners, Field Medalists, annual international ACM software coding college competitions and the most brilliant inventors/innovators. Therefore average IQ is only part of the story, and there is no reason to believe that a white-northeast Asian hybrid population will produce as many intellectually outstanding people per capita as present-day northern Europeans do.

Ziv hilariously writes, “Once true interracial marriage becomes commonplace, I think we will see an even bigger boost in the physical and mental development of future generations.” Really? If the U.S./U.K. Ashkenazim diaspora, northeast Asians and northern Europeans were to mass-absorb the likes of Bushmen (IQ = 54), Australian aborigines (IQ = 62), black Africans in general (IQ = 67) or south Asians (IQ = 82) (see Lynn[81]), would one expect a boost in mental development from the perspective of the high IQ groups?

Another useful consideration is as follows. Assume that there are no deleterious effects of race mixing. From a strictly IQ perspective, if a white man with an IQ of 100 had to choose between a white woman and a Bangladeshi woman, both with an IQ of 130, which would be the better choice? If additive genetics accounted for all the variation in IQ between individuals, one would expect the offspring of the union in consideration to have an IQ around 115, but about 40% of the IQ variation between individuals is accounted for by additive genetics, i.e., the white man can expect an IQ boost that is 40% of 15 points, i.e., 6 points. Therefore, the offspring will have a range of IQ centering around 106. Now, given white and Bangladeshi average IQs of 100 and low 80s, respectively, a 130-IQ Bangladeshi is much more of an outlier for her race than a 130-IQ white is. In other words, the contribution of additive genetics from the Bangladeshi woman would result in a probable IQ of the hybrid offspring leaning toward the lower range of the distribution centering around 106 compared to the white woman. As noted above, deleterious alleles are implicated in the Ashkenazim IQ advantage[80], and it has been documented that people with very high IQs tend to have an above average incidence of myopia and atopic disorders (related to autonomic nervous system disruption) such as asthma and allergies[82]. Therefore, the odds that abnormal genetics/developmental events are implicated in the 130-IQ of the Bangladeshi woman are greater. In other words, the better choice is clearly the white woman. Hence, even if one assumes no harm resulting from race mixing, from a strictly IQ perspective, a white person is better off breeding with a white than a member of the dark races with the same IQ as a prospective white partner. If deleterious alleles are mostly responsible for the Ashkenazim IQ advantage, then it is not worth it for whites to breed with the Ashkenazim. Additionally, northeast Asians are know to have lower verbal IQs than whites, and from an IQ perspective, no racial benefits from absorbing them are apparent given that notwithstanding their math advantage, when it comes to manifesting math prowess at the highest levels (e.g., work deserving of the Field Medal), northeast Asians, in spite of their much greater numbers, are far behind whites.

Conclusions

Ziv makes a very weak case, and has undoubtedly omitted inconvenient data. Giving the process of manuscript submission to final publication about an year’s time, Ziv should easily have come across the citations in this review that were published/put online prior to mid-2005. The evidence that he has ignored makes the opposite case. None of the heavily mixed populations --mestizos/mulattos in south America, Middle Eastern/North African people, south Asians, southeast Asians or central Asians -- are known for great health, vigor, attractiveness or high intelligence. I will speculate on Ziv’s motives below, but the implications of his work should be briefly addressed. From the perspectives of kinship and ethnic genetic interests (EGI), both of which Ziv ignores, Ziv’s ideas are horrible; see comments by “On Holliday” here and a fuller discussion of EGI here. In the biological sciences, there is consensus that living organisms be preserved at the level of kinds, i.e. races and higher order levels of taxonomy, unless one is looking at a virus/microorganism that is deadly for humans. Only if conservation efforts are threatened by inbreeding depression will there be a recommendation to mix races or species (in plants) to preserve broad taxonomical groups, and Ziv’s message will normally be treated with contempt in a non-human context. The concept of ethnic genetic interests basically argues that one’s race is worth preserving because it is one’s own, not because there is any special value to it. However, it is also worthwhile to consider the value of things to determine what is and what isn’t worthy of preservation, and white physical appearance and the ability of northern Europeans to produce the highest number of intellectually outstanding people per capita in the absence of having accumulated deleterious alleles, like the Ashkenazim have, is of sufficient value to be at least preserved if not enhanced, and speaking of enhancement, this will come about by evolution within whites; absorbing non-whites will result in devolution. Ziv’s recommendations will be especially disastrous for whites from an aesthetics and intelligence standpoint if many white people are persuaded by his arguments.

What has motivated Alon Ziv?

Attempting to critique an argument by questioning the motives of the author is bad practice, and is specifically known as deconstruction, but I have provided plenty of criticism, and do not intend this section to be a form of criticism. Rather, given the destructive nature of Ziv’s thesis, it is of some interest to question what could have prompted a man with an apparently adequate background in the biological sciences, and one who appears to have spent years reading relevant studies, to present very selective evidence in favor of his arguments and ignore a large body of evidence making the opposite case.

Ziv tells us that his book is not an instruction manual, i.e., he is not telling us to pick a spouse based on racial criteria. He also notes that he doesn’t need to instruct people to seek interracial unions because they are inevitable. He tells the reader to “get ready for a mixed race explosion.” He writes that “interracial marriage is the future, not because it should be, but simply because it is.” And, as to why it is going to be this way, it is because of continued immigration of people of various races into the U.S. as well as other Western nations, and people’s altered mating preferences in accordance with the snow geese example.

Well then, why write a book extolling the virtues of race mixing if it is going to happen on a large scale no matter what Ziv or other people say? The answer is surely not that Ziv merely decided to document what is going to happen in the future, as should be obvious from the tone of the book and Ziv’s very selective citations. The answer is easy to figure out. Ziv laments that although Gary, Indiana (U.S.A.) has 430,000 whites and 120,000 blacks, blacks and whites are highly segregated in this city; he even calls this depressing! It appears that race mixing in the U.S. is not occurring on a scale that would please Ziv, and he has decided to help accelerate it. Ziv writes, “For the modern world, it would be far better to seek out the most genetically distinct mate possible.” He tells us that “the higher one’s heterozygosity is, the better it is,” and then tells us that the combination that would yield the highest heterozygosity would be the combination of a black African with a non-African, a Bantu-Eskimo mating yielding the highest heterozygosity of all interracial matings, according to the research of Cavalli-Sforza. Ziv is quick to add that he is not advocating a race of Bantu-Eskimo supermen, but greater heterozygoisty has its benefits.

One factor that could have motivated Ziv to write this book is that he genuinely subscribes to his thesis and is so enthusiastic about the virtues of race mixing that he has skipped evidence to the contrary, believing that the weight of the evidence in the long run will eventually vindicate him. Another possibility is that Ziv is motivated by malice, a feeling that I cannot shake off.

It would be interesting to learn about the racial background(s) of the women that Ziv has dated and who he ultimately has children with; if she turns out to be non-Jewish and non-white, I can see myself giving Ziv the benefit of the doubt and believe that his book reflects his genuine conviction about the benefits of race mixing, but if this woman is Jewish or white, then my suspicion that Ziv is motivated by malice would be strengthened. Ziv lives in Los Angeles and should have no problems finding a willing black, Asian or Hispanic woman. However, if I had to bet, I would wager that Ziv would prefer a Nordic white for a breeding partner. Ziv doesn’t tell us about the kind of women he likes, but he describes his first love, a classmate, Leslie, in seventh grade. The only thing he tells us about her physical appearance is that she had honey blonde hair, and his description makes it obvious that he was enamored by her blondeness. Of course, if Ziv mated with Leslie, his offspring would not have honey blond hair anymore than if she mated with any non-white, but Ziv does not address this kind of loss resulting from race mixing.

Citations

1. Bogaert AF. Asexuality: prevalence and associated factors in a national probability sample. J Sex Res. Aug 2004;41(3):279-287.
2. Alikasifoglu M, Erginoz E, Ercan O, Albayrak-Kaymak D, Uysal O, Ilter O. Sexual abuse among female high school students in Istanbul, Turkey. Child Abuse Negl. Mar 2006;30(3):247-255.
3. Crowley MS, Seery BL. Exploring the multiplicity of childhood sexual abuse with a focus on polyincestuous contexts of abuse. J Child Sex Abus. 2001;10(4):91-110.
4. Kim HS, Kim HS. Incestuous experience among Korean adolescents: prevalence, family problems, perceived family dynamics, and psychological characteristics. Public Health Nurs. Nov-Dec 2005;22(6):472-482.
5. Simmons LW, Rhodes G, Peters M, Koehler N. Are human preferences for facial symmetry focused on signals of developmental instability? Behav Ecol. 2004;15(5):864-871.
6. Rosenberg NA, Mahajan S, Ramachandran S, Zhao C, Pritchard JK, Feldman MW. Clines, clusters, and the effect of study design on the inference of human population structure. PLoS Genet. Dec 2005;1(6):e70.
7. Rosenberg NA, Pritchard JK, Weber JL, et al. Genetic structure of human populations. Science. Dec 20 2002;298(5602):2381-2385.
8. Nei M, Roychoudhury AK. Evolutionary relationships of human populations on a global scale. Mol Biol Evol. Sep 1993;10(5):927-943.
9. Hennessy RJ, Stringer CB. Geometric morphometric study of the regional variation of modern human craniofacial form. Am J Phys Anthropol. Jan 2002;117(1):37-48.
10. Li YY, Brace CL, Gao QA, Tracer DP. Dimensions of face in Asia in the perspective of geography and prehistory. Am J Phys Anthropol. Jul 1991;85(3):269-279.
11. Serre D, Paabo S. Evidence for gradients of human genetic diversity within and among continents. Genome Res. Sep 2004;14(9):1679-1685.
12. Freese J, Meland S. Seven tenths incorrect: heterogeneity and change in the waist-to-hip ratios of Playboy centerfold models and Miss America pageant winners. J Sex Res. May 2002;39(2):133-138.
13. Marlowe FW, Wetsman A. Preferred waist-to-hip ratio and ecology. Personal Individ Diff. 2001;30(3):481-489.
14. Sugiyama L. Is beauty in the context-sensitive adaptations of the beholder? Shiwiar use of waist-to-hip ratio in assessments of female mate value. Evol Hum Behav. 2004;25(1):51-62.
15. Yu DW, Shepard GH, Jr. Is beauty in the eye of the beholder? Nature. Nov 26 1998;396(6709):321-322.
16. Furlow B, Gangestad SW, Armijo-Prewitt T. Developmental stability and human violence. Proc R Soc Lond B Biol Sci. Jan 7 1998;265(1390):1-6.
17. Manning JT, Wood D. Fluctuating asymmetry and aggression in boys. Hum Nature. 1998;9:53-65.
18. Aspi J. Inbreeding and outbreeding depression in male courtship song characters in Drosophila montana. Heredity. Mar 2000;84 ( Pt 3):273-282.
19. Galloway LF, Etterson JR. Population differentiation and hybrid success in Campanula americana: geography and genome size. J Evol Biol. Jan 2005;18(1):81-89.
20. Heiser DA, Shaw RG. The fitness effects of outcrossing in Calylophus serrulatus, a permanent translocation heterozygote. Evolution Int J Org Evolution. Jan 2006;60(1):64-76.
21. Henry PY, Pradel R, Jarne P. Environment-dependent inbreeding depression in a hermaphroditic freshwater snail. J Evol Biol. Nov 2003;16(6):1211-1222.
22. LeBas NR. Mate choice, genetic incompatibility, and outbreeding in the ornate dragon lizard, Ctenophorus ornatus. Evolution Int J Org Evolution. Feb 2002;56(2):371-377.
23. Miller LM, Close T, Kapuscinski AR. Lower fitness of hatchery and hybrid rainbow trout compared to naturalized populations in Lake Superior tributaries. Mol Ecol. Nov 2004;13(11):3379-3388.
24. Montalvo AM, Ellstrand NC. Nonlocal transplantation and outbreeding depression in the subshrub Lotus scoparius (Fabaceae). Am J Bot. Feb 2001;88(2):258-269.
25. Neff BD. Stabilizing selection on genomic divergence in a wild fish population. Proc Natl Acad Sci U S A. Feb 24 2004;101(8):2381-2385.
26. Parisod C, Trippi C, Galland N. Genetic variability and founder effect in the pitcher plant Sarracenia purpurea (Sarraceniaceae) in populations introduced into Switzerland: from inbreeding to invasion. Ann Bot (Lond). Jan 2005;95(2):277-286.
27. Peer K, Taborsky M. Outbreeding depression, but no inbreeding depression in haplodiploid Ambrosia beetles with regular sibling mating. Evolution Int J Org Evolution. Feb 2005;59(2):317-323.
28. Quilichini A, Debussche M, Thompson JD. Evidence for local outbreeding depression in the Mediterranean island endemic Anchusa crispa Viv. (Boraginaceae). Heredity. Aug 2001;87(Pt 2):190-197.
29. Shpak M. The role of deleterious mutations in allopatric speciation. Evolution Int J Org Evolution. Jul 2005;59(7):1389-1399.
30. Waser NM, Price MV, Shaw RG. Outbreeding depression varies among cohorts of Ipomopsis aggregata planted in nature. Evolution Int J Org Evolution. Apr 2000;54(2):485-491.
31. Willi Y, Van Buskirk J. Genomic compatibility occurs over a wide range of parental genetic similarity in an outcrossing plant. Proc Biol Sci. Jul 7 2005;272(1570):1333-1338.
32. Khongsdier R, Mukherjee N. Effects of heterosis on growth in height and its segments: a cross-sectional study of the Khasi girls in Northeast India. Ann Hum Biol. Sep-Oct 2003;30(5):605-621.
33. Hulse FS. Exogamy and heterosis. Year Phys Anthropol. 1957;9:240-257.
34. Wolanski N, Jarosz E, Pyzuk M. Heterosis in man: growth in offspring and distance between parents' birthplaces. Soc Biol. Mar 1970;17(1):1-16.
35. Hegele RA. Genetic prediction of atherosclerosis: lessons from studies in native Canadian populations. Clin Chim Acta. Aug 1999;286(1-2):47-61.
36. Hegele RA, Ban MR, Carrington CV, Ramdath DD. Allele frequencies for candidate genes in atherosclerosis and diabetes among Trinidadian neonates. Hum Biol. Aug 2001;73(4):525-531.
37. North KE, MacCluer JW, Williams JT, et al. Evidence for distinct genetic effects on obesity and lipid-related CVD risk factors in diabetic compared to nondiabetic American Indians: the Strong Heart Family Study. Diabetes Metab Res Rev. Mar-Apr 2003;19(2):140-147.
38. Helgadottir A, Manolescu A, Helgason A, et al. A variant of the gene encoding leukotriene A4 hydrolase confers ethnicity-specific risk of myocardial infarction. Nat Genet. Jan 2006;38(1):68-74.
39. Radha V, Vimaleswaran KS, Babu HN, et al. Role of genetic polymorphism peroxisome proliferator-activated receptor-gamma2 Pro12Ala on ethnic susceptibility to diabetes in South-Asian and Caucasian subjects: Evidence for heterogeneity. Diabetes Care. May 2006;29(5):1046-1051.
40. Livshits G, Otremski I, Kobyliansky E. Longitudinal growth of infants in families of "mixed" and "non-mixed" ethnic origin in Israel. Hum Biol. Dec 1987;59(6):933-949.
41. Leamy LJ, Meagher S, Taylor S, Carroll L, Potts WK. Size and fluctuating asymmetry of morphometric characters in mice: their associations with inbreeding and t-haplotype. Evolution Int J Org Evolution. Nov 11 2001;55(11):2333-2341.
42. Beacham TD. Developmental stability, heterozygosity, and genetic analysis of morphological variation in pink salmon (Oncorhynchus gorbuscha). Can J Zool. 1991;69(2):274-278.
43. Clarke GM, Oldroyd BP. The genetic basis of developmental stability in Apis mellifera. II. Relationships between character size, asymmetry and single-locus heterozygosity Genetica. 1996;97(2):211-224.
44. Vollestad LA, Hindar K. Developmental stability and environmental stress in Salmo salar (Atlantic salmon). Heredity. Feb 1997;78 ( Pt 2):215-222.
45. Thornhill R, Moller AP. Developmental stability, disease and medicine. Biol Rev Camb Philos Soc. Nov 1997;72(4):497-548.
46. Livshits G, Kobyliansky E. Lerner's concept of developmental homeostasis and the problem of heterozygosity level in natural populations. Heredity. Dec 1985;55 ( Pt 3):341-353.
47. Vollestad LA, Hindar K, Moller AP. A meta-analysis of fluctuating asymmetry in relation to heterozygosity. Heredity. Aug 1999;83 ( Pt 2):206-218.
48. Udry JR, Li RM, Hendrickson-Smith J. Health and behavior risks of adolescents with mixed-race identity. Am J Public Health. Nov 2003;93(11):1865-1870.
49. Vandervoort DJ, Divers PP, Aojido C. Psychosocial correlates of health status among Asians, Caucasians, and multiracial subjects. Current Psychology: Developmental, Learning, Personality, Social. 2000;19(2):120-128.
50. Choi Y, Harachi TW, Gillmore MR, Catalano RF. Are multiracial adolescents at greater risk? Comparisons of rates, patterns, and correlates of substance use and violence between monoracial and multiracial adolescents. Am J Orthopsychiatry. Jan 2006;76(1):86-97.
51. Gibbs JT. Identity and marginality: issues in the treatment of biracial adolescents. Am J Orthopsychiatry. Apr 1987;57(2):265-278.
52. Gibbs JT, Moskowitz-Sweet G. Clinical and cultural issues in the treatment of biracial and bicultural adolescents. Families in Society. 1991;72:479-591.
53. Johnson R, Nagoshi C. The adjustment of offspring of withingroup and interracial/intercultural marriages: A comparison of personality factor scores. J Marriage Family. 1986;48:279-284.
54. Radina ME, Cooney TM. Relationship quality between multiracial adolescents and their biological parents. Am J Orthopsychiatry. Oct 2000;70(4):445-454.
55. Cooney TM, Radina ME. Adjustment problems in adolescence: are multiracial children at risk? Am J Orthopsychiatry. Oct 2000;70(4):433-444.
56. Barnett AH, Dixon AN, Bellary S, et al. Type 2 diabetes and cardiovascular risk in the UK south Asian community. Diabetologia. Oct 2006;49(10):2234-2246.
57. Forouhi NG, Sattar N, Tillin T, McKeigue PM, Chaturvedi N. Do known risk factors explain the higher coronary heart disease mortality in South Asian compared with European men? Prospective follow-up of the Southall and Brent studies, UK. Diabetologia. Sep 14 2006.
58. Gupta M, Brister S. Is South Asian ethnicity an independent cardiovascular risk factor? Can J Cardiol. Mar 1 2006;22(3):193-197.
59. Smith J, Cianflone K, Al-Amri M, Sniderman A. Body composition and the apoB/apoA-I ratio in migrant Asian Indians and white Caucasians in Canada. Clin Sci (Lond). Sep 2006;111(3):201-207.
60. Bedi US, Singh S, Syed A, Aryafar H, Arora R. Coronary artery disease in South Asians: an emerging risk group. Cardiol Rev. Mar-Apr 2006;14(2):74-80.
61. Tewari S, Kumar S, Kapoor A, et al. Premature coronary artery disease in North India: an angiography study of 1971 patients. Indian Heart J. Jul-Aug 2005;57(4):311-318.
62. Davey G, Ramachandran A, Snehalatha C, Hitman GA, McKeigue PM. Familial aggregation of central obesity in Southern Indians. Int J Obes Relat Metab Disord. Nov 2000;24(11):1523-1527.
63. Potts J, Simmons D. Sex and ethnic group differences in fat distribution in young United Kingdom South Asians and Europids. J Clin Epidemiol. Aug 1994;47(8):837-841.
64. Dudeja V, Misra A, Pandey RM, Devina G, Kumar G, Vikram NK. BMI does not accurately predict overweight in Asian Indians in northern India. Br J Nutr. Jul 2001;86(1):105-112.
65. Misra A, Pandey RM, Sinha S, Guleria R, Sridhar V, Dudeja V. Receiver operating characteristics curve analysis of body fat & body mass index in dyslipidaemic Asian Indians. Indian J Med Res. Apr 2003;117:170-179.
66. Vikram NK, Misra A, Pandey RM, et al. Anthropometry and body composition in northern Asian Indian patients with type 2 diabetes: receiver operating characteristics (ROC) curve analysis of body mass index with percentage body fat as standard. Diabetes Nutr Metab. Feb 2003;16(1):32-40.
67. Nanan DJ. The obesity pandemic--implications for Pakistan. J Pak Med Assoc. Aug 2002;52(8):342-346.
68. Singh V, Deedwania P. Dyslipidemia in special populations: Asian Indians, African Americans, and Hispanics. Curr Atheroscler Rep. Jan 2006;8(1):32-40.
69. Tomkinson GR, Olds TS. Physiological correlates of bilateral symmetry in humans. Int J Sports Med. Nov 2000;21(8):545-550.
70. Tomkinson GR, Popovic N, Martin M. Bilateral symmetry and the competitive standard attained in elite and sub-elite sport. J Sports Sci. Mar 2003;21(3):201-211.
71. Rhodes G. The evolutionary psychology of facial beauty. Annu Rev Psychol. 2006;57:199-226.
72. Martinez-Abadias N, Gonzalez-Jose R, Gonzalez-Martin A, et al. Phenotypic evolution of human craniofacial morphology after admixture: a geometric morphometrics approach. Am J Phys Anthropol. Mar 2006;129(3):387-398.
73. Chung CS, Runck DW, Bilben SE, Kau MC. Effects of interracial crosses on cephalometric measurements. Am J Phys Anthropol. Apr 1986;69(4):465-472.
74. Rhodes G, Lee K, Palermo R, et al. Attractiveness of own-race, other-race, and mixed-race faces. Perception. 2005;34(3):319-340.
75. Nagoshi CT, Johnson RC. The ubiquity of g. Personal Individ Diff. 1986;7(2):201-207.
76. Mingroni MA. The secular rise in IQ: giving heterosis a closer look. Intelligence. 2004;32(1):65-83.
77. Colom R, Lluis-Font JM, Andres-Pueyo A. The generational intelligence gains are caused by decreasing variance in the lower half of the distribution: Supporting evidence for the nutrition hypothesis. Intelligence. 2005;33:83-91.
78. Lynn R. The intelligence of American Jews. Personal Individ Diff. 2004;36(1):201-207.
79. Lynn R, Longley D. On the high intelligence and cognitive achievements of Jews in Britain. Intelligence. 2006;Epub (ahead of print).
80. Cochran G, Hardy J, Harpending H. Natural history of Ashkenazi intelligence. J Biosoc Sci. Sep 2006;38(5):659-693.
81. Lynn R. Race differences in intelligence : an evolutionary analysis. Augusta, GA: Washington Summit Publishers; 2006.
82. Benbow CP. Physiological correlates of extreme intellectual precocity. Neuropsychologia. 1986;24(5):719-725.

The trackback URL for this entry is: http://majorityrights.com/index.php/trackback/3037/yS91mTg0/

Trackbacks:

Comments:

Page 2 of 2 pages  <  1 2

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---