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RETRACTED: Do pigmentation and the melanocortin system modulate aggression and sexuality in humans as they do in other animals?
... (Ansara and Hegarty, 2012), and sexism (Ruti, 2015). A racialised psychology has proliferated with arguments around brain size, genetics and intelligence dominating the works of researchers such as Rushton (Rushton and Templer, 2012) funded by organisations described as holding neo-nazi, eugenic ideologies (Rosenthal, 1995;see Teo (2011) for an excellent breakdown on empirical race psychology). ...
... It was only in 2020 that an article (Rushton and Templer, 2012) which claimed melatonin in skin made Black people less intelligent, more aggressive, and more prone to criminality was retracted. This scientific rationality of objectivity has defended practices like the pathologisation of minority sexualities and genders, the use of lobotomies, mass institutionalisation, and installed the same focus that removes attention from systematic inequality and positions blames on individuals for having poor mental health instead of addressing social crisis (Fondacaro and Weinberg, 2002). ...
... While this paper was published in 2012, the current Editor-in-Chief and Senior Associate Editors now have the responsibility to address all matters arising from it. Rushton and Templer (2012) contend that animal studies show that dark skin pigmentation is reliably related to increased aggression and sexual activity. They speculate that the same may be true in humans, and claim that the psychological literature supports this contention that is grounded in evolutionary theory. ...
... It is on the basis of our analysis supported by input from experts that forms the grounds for issuing a retraction decision of the Rushton and Templer (2012) ...
... Science Example 2: Rushton and Templer (2012) published an article that claimed the results from psychological studies combined with animal studies evidence strongly indicated that people with darker skin color were prone to more aggression and sexual activity. The journal, Personality and Individual Differences, retracted the article after other scholars expressed their outrage, identified the article as racist, and provided evidence to negate the conclusions of Rushton and Templer (Sapunar 2020). ...
... The captured albino mutant individuals of the wild Rattus norvegicus were one of the earliest type of rats domesticated for scientific purpose. One of the reason could have been related to the pleiotropic association of melanin-based lighter coloration to certain attributes of social behavior such as tameness [12,13]. The albino rats have become extremely popular in experimental psychology, neurology and physiology in the mid-20 th century [14]. ...
Selective breeding of laboratory rats resulted in changes of their behavior. Concomitantly, the albino strains developed vision related pathologies. These alterations certainly occurred on the background of modifications in brain morphology. The aim of the study was to assess and compare volumes of major structures in brains of wild-captive, laboratory albino and laboratory pigmented rats. High resolution T2-weighted images of brains of adult male Warsaw Wild Captive Pisula-Stryjek rats (WWCPS, a model of wild type), laboratory pigmented (Brown Norway strain, BN) and albino rats (Wistar strain, WI) were obtained with a 7T small animal-dedicated magnetic resonance tomograph. Volume quantification of whole brains and 50 brain structures within each brain were performed with the digital Schwarz rat brain atlas and a custom-made MATLAB/SPM8 scripts. Brain volumes were scaled to body mass, whereas volumes of brain structures were normalized to individual brain volumes. Normalized brain volume was similar in WWCPS and BN, but lower in WI. Normalized neo-cortex volume was smaller in both laboratory strains than in WWCPS and the visual cortex was smaller in albino WI rats than in WWCPS and BN. Relative volumes of phylogenetically older structures, such as hippocampus, amygdala, nucleus accumbens and olfactory nuclei, also displayed certain strain-related differences. The present data shows that selective breeding of laboratory rats markedly affected brain morphology, the neocortex being most significantly altered. In particular, albino rats display reduced volume of the visual cortex, possibly related to retinal degeneration and the development of blindness.
... IQ and homicide specifically are also negatively associated. Rushton and Templer (2012) found a similar negative pattern between homicide and IQ across 116 nations. Overall, the individual, intranational, and international comparisons indicate a consistent negative connection between IQ and the occurrence of violent crimes, including homicide. ...
A considerable number of publications have examined the effect of various geographical, life history, social, economic and political factors on homicide. However, few studies were interested in examining the effect of these forces in an integrated social biogeography of homicide. This study collected data for 172 nation-states from various publications and databases. Standardized Studentized residuals were extracted from a multilevel model examining the effects of geographical adjacency upon homicide rates. A general linear model was used, with the residuals, to observe the effects of physical, community, social, cultural, and cognitive ecology upon homicide. Two sequential canonical analyses (SEQCA) were conducted to determine the mediating effects among the ecological indicators with respect to homicide. In the SEQCA, we hypothesized physical ecology would lead to communal ecology, in turn leading to social ecology, subsequently leading to cognitive ecology, and ultimately to homicide. A parsimony test concluded that economic growth and inequality fully mediated the relationship between cognitive ecology and homicideresiduals.Similarly,theeffectsoflifehistoryuponhomicidewerefullymediated by social ecology. This study suggests several social ecology factors appear to directly affect homicide; however, other aspects of ecology indirectly affected homicide through influences on social ecology. The effect of indicators of social ecology such as income inequality and the operational sex ratio indicate competition for resources is a significant force generating differences in homicide rates across populations. In conclusion, a suite of evolutionary pressures seems to influence homicide rates, but mainly in a sequential nature rather than simultaneously.
... Across vertebrates, melanin-based pigmentation has been associated with aggression, i.e., darker animals are more aggressive (Ducrest et al., 2008;Rushton and Templer, 2012). For instance, male Great Tits (Parus major) with a larger black (melanin-based) stripe area defended their territory more vigorously (Quesada and Senar, 2007) and male lions (Panthera leo) with darker manes are more aggressive (West and Packer, 2002). ...
Social interaction is stressful and subordinate individuals are often subjected to chronic stress, which greatly affects both their behavior and physiology. In teleost fish the social position of an individual may have long-term effects, such as effects on migration, age of sexual maturation or even sex. The brain serotonergic system plays a key role in coordinating autonomic, behavioral and neuroendocrine stress responses. Social subordination results in a chronic activation of the brain serotonergic system an effect, which seems to be central in the subordinate phenotype. However, behavioral effects of short-term acute activation of the serotonergic system are less obvious. As in other vertebrates, divergent stress coping styles, often referred to as proactive and reactive, has been described in teleosts. As demonstrated by selective breeding, stress coping styles appear to be partly heritable. However, teleost fish are characterized by plasticity, stress coping style being affected by social experience. Again, the brain serotonergic system appears to play an important role. Studies comparing brain gene expression of fish of different social rank and/or displaying divergent stress coping styles have identified several novel factors that seem important for controlling aggressive behavior and stress coping, e.g., histamine and hypocretin/orexin. These may also interact with brain monoaminergic systems, including serotonin.
... T-treated males have greater expression of melanocortin receptor 4 (MC4R) in the hypothalamus. MC4R binds to α-melanocyte stimulating hormone (αMSH), a peptide hormone best known for its influence on coloration, but also for its pleiotropic effects on appetite, metabolism, sexual function, and aggressive behavior (Rushton and Templer, 2012). Neural AROM expression is also up-regulated in response to T implants in juncos. ...
Social challenges from rival conspecifics are common in the lives of animals, and changes in an animal's social environment can influence physiology and behavior in ways that appear to be adaptive in the face of continued social instability (i.e. social priming). Recently, it has become clear that testosterone, long thought to be the primary mediator of these effects, may not always change in response to social challenges, an observation that highlights gaps in our understanding of the proximate mechanisms by which animals respond to their social environment. Here, our goal is to address the degree to which testosterone mediates organismal responses to social cues. To this end, we review the behavioral and physiological consequences of social challenges, as well as their underlying hormonal and gene regulatory mechanisms. We also present a new case study from a wild songbird, the dark-eyed junco Junco hyemalis, in which we find largely divergent genome-wide transcriptional changes induced by social challenges and testosterone, respectively, in muscle and liver tissue. Our review underscores the diversity of mechanisms that link the dynamic social environment with an organisms' genomic, hormonal, and behavioral state. This diversity among species, and even among tissues within an organism, reveals new insights into the pattern and process by which evolution may alter proximate mechanisms of social priming.
... Interestingly, the more melanised animals that typically are more aggressive [15,16] also seem to be more stress resilient [15]. Similar results have also been reported in teleost fish. ...
Pigmentation often signals status and in general melanin-based pigmentation is indicative of aggression and stress resilience in vertebrates. This is evident in the salmonids Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) where more melanin spotted individuals are more stress resilient. However, in the salmonid Arctic charr (Salvelinus alpinus) it seems as if it is carotenoid-based pigmentation that signals aggression and stress resilience. In our study, social stress effects on carotenoid-based spots, and behavioural and physiological stress responses were investigated. Socially stressed individuals have more spots, and behavioural stress responses were associated with spots. Some of the results concerning physiological stress responses, such as plasma cortisol levels and monoaminergic activity, are associated with spottiness. Further, the earlier proposed lateralization of spots, with left side connected to stress responsiveness and right side to aggression, is to some extent validated although not conclusively. In conclusion, this study provides further evidence that more stressed charr have more carotenoid spots, and for the first time monoaminergic activity is shown to be connected with carotenoid pigmentation.
Copyright © 2015. Published by Elsevier B.V.
... Further, melanin-based pigmentation has in general been linked to behaviour in various vertebrates [10,11]. For instance, melanin-based pigmentation correlates positively with aggression in mammals [12] and birds [13][14][15][16]. ...
... 10. Hair color, which may indicate the proportion of northern ancestry and/or paedomorphism, it may also be related to life history via the melanocortin system (Ducrest et al., 2008;Rushton & Templer, 2012). This was computed as the mean of the percentage of blond hair and the percentage of dark hair (reverse-scored) in each county. ...
SD–IE is a strategic differentiation effect present amongst indices of life history (LH), such that persons and populations of slow LH are more differentiated compared to those of fast LH. We found that this phenomenon is present amongst provinces in Italy and Spain, similarly to demonstrations among US states and Japanese prefectures. The average effect size of SD–IE was found to be bigger in Spain and Italy. We also tested cognitive differentiation as a function of life history speed and IQ (high-K and high-IQ provinces having higher cognitive differentiation), and found that these effects are also present in the Italian and Spanish regions. Most cognitive differentiation effects were statistically significant in spite of the small number of provinces, but all trended in the predicted direction. We discuss the findings from a bio-historical perspective, taking into account the ethnic variability present in Spain and Italy.
... This might be the reason that people in the former prefectures have lighter skin than those in the latter. Skin whiteness is positively correlated with latitude (r = 0.47) and also with IQ (r = 0.42), as studies based on both theoretical and empirical grounds (Meisenberg, 2004;Rushton & Templer, 2012;Templer & Arikawa, 2006;Templer & Rushton, 2011). It would be also due to genetic admixture with south east Asians from the sea route, although there exists no such description in the written history that dates back to 1500 years ago. ...
Regional differences in IQ are estimated for 47 prefectures of Japan. IQ scores obtained from official achievement tests show a gradient from north to south. Latitudes correlate with height, IQ, and skin color at r = 0.70, 0.44, 0.47, respectively. IQ also correlates with height (0.52), skin color (0.42), income (0.51) after correction, less homicide rate (− 0.60), and less divorce (− 0.69) but not with fertility infant mortali'ty. The lower IQ in southern Japanese islands could be attributable to warmer climates with less cognitive demand for more than fifteen hundred years.
The core of systemic racism and sexism is not merely an emphasis about human differences and thinking that another group of people is inferior to one's own. Rather, the institutional nature of racism or sexism establishes a permanent group hierarchy that is believed to reflect the laws of nature or the decrees of God. It thus becomes the norm of a culture to think and behave according to these rules. Notions of hierarchy became solidified into the Great Chain of Being during the Middle Ages, as did views concerning hereditary racial and gender superiority. During the Enlightenment, such classifications became established by philosophy and science. Starting in the 1800s, embryology and anthropology were used to provide evidence for the unilinear progression of species and races. The first evolutionary schemes were not “branching trees.” In these schemes, women and non-white races were seen as embryonic or juvenile forms of the adult white male, and they were often depicted as intermediaries between the fully human and the animals. Such linear schemes of evolution remain part of popular culture and even some science, promoting the racism and sexism associated with them.
We revisit an old theory proposed by Lynn, connecting race differences in criminality and psychopathy with r/k selection. The origin of this group-difference is attributed to cold-selection in the Pleistocene. We contend that newer models of Life History Theory provide a better rubric within which to evaluate Lynn's arguments as a) they better account for the adaptive logic of the coherence pattern among the traits characteristic of so-called 'psychopathic personality', b) provide a normatively free language with which group differences in behavior can be described, and c) make predictions at the level of both the individual and intra-individual (developmental) levels, which permit the role of environmental contributions to these dispositions to be better comprehended. Thus newer approaches to understanding life history are necessarily more empirically nuanced. We also consider the merits of future, more systematic studies along the lines of Lynn's contribution.
The present study extends the findings of Lynn (2010), who reported higher mean IQ in northern than southern Italy and of Templer (2012), who found biological correlates of IQ in the Italian regions. The present study found that murder and attempted murder rates were associated with Mediterranean/Mideastern characteristics (lower IQ, black hair, black eyes) and that lower murder rates were associated with central/northern European characteristics (higher cephalic index, blond hair, blue eyes, and higher multiple sclerosis and schizophrenia rates). The eye and hair color findings are consistent with the human and animal literature finding of darker coloration associated with greater aggression.
The phenomena of strategic and cognitive differentiation and integration (SD–IE and CD–IE) amongst life history indicators and cognitive abilities as a function of level of latent life history speed have been robustly demonstrated in individual differences samples. Here we examine a cross-national sample (N = 76 nations) with respect to ten aggregate life history indicators (birth rate, infant mortality, skin reflectance, prevalence of STDs, overall life satisfaction, life expectancy, national IQ, cranial capacity, savings rate and crime rate), all of which share substantive common variance stemming from a K-Super factor which accounts for 66.6% of the variance amongst these indicators. All indicators became signifi-cantly less strongly correlated with the super factor as the level of K increased indicating the presence of robust SD–IE effects. A 'cognitive' factor comprised of the national IQ and cranial capacity variables also exhibited differentiation as a function of increasing levels of K, suggesting the presence of CD–IE also. Consistently with the findings of individual differences studies investigating SD–IE, the degree to which the indicators loaded on the K super-factor positively mediated their sensitivity to the effect.
This study investigates the dimensions of cultural variation in the modern world as assessed by the World Values Survey. It confirms the previously reported existence of two major dimensions of cultural variation that can be described as “modern” and “postmodern,” respectively. Modern values are characterized by skepticism and critical thinking, with a rejection of religion and traditional authority along with an interest in politics. In multiple regression models, modern values are directly related to the IQ of the population. Postmodern values are characterized by trust, tolerance, and self-realization. In multiple regression models, they are inversely related to corruption. Subjective well-being is positively related to postmodern values and negatively to modern values. Modern values are interpreted as the emancipation of reason from the constraints of traditional custom and religion, and postmodern values as the emancipation of pleasure-seeking and social emotions from the constraints of dysfunctional social systems. The historical context and the roles of these value orientations in the evolution of contemporary societies are discussed.
This study investigates the dimensions of cultural variation in the modern world as assessed by the World Values Survey. It confirms the previously reported existence of two major dimensions of cultural variation that can be described as modern and "postmodern," respectively. Modern values are characterized by skepticism and critical thinking, with a rejection of religion and traditional authority along with an interest in politics. In multiple regression models, modern values are directly related to the IQ of the population. Postmodern values are characterized by trust, tolerance, and self-realization. In multiple regression models, they are inversely related to corruption. Subjective well-being is positively related to postmodern values and negatively to modern values. Modern values are interpreted as the emancipation of reason from the constraints of traditional custom and religion, and postmodern values as the emancipation of pleasure-seeking and social emotions from the constraints of dysfunctional social systems. The historical context and the roles of these value orientations in the evolution of contemporary societies are discussed.
Dentition is arguably the most stable marker of maturation: dental development is highly heritable, is relatively resistant to nutritional extremes and even fairly severe developmental insults, and has a lower coefficient of variation than skeletal maturation. Tooth development must be completely integrated into the plant of growth and development, timed to growth of the skull, maturation of muscles of mastication, and stomatic growth in general. Data on age of maturity of the dentition are here added to other measures of primate life history. -from Author
This paper proposes that there are racial and ethnic differences in psychopathic personality conceptualised as a continuously distributed trait, such that high values of the trait are present in blacks and Native Americans, intermediate values in Hispanics, lower values in whites and the lowest values in East Asians. Part one of the paper sets out the evidence for this thesis. Part two applies the thesis to the unresolved problem in The Bell Curve that racial and ethnic differences in a number of social phenomena such as crime, welfare dependency, rates of marriage, etc. cannot be fully explained by differences in intelligence and proposes that some of the residual disparities are attributable to differences in psychopathic personality. Part three of the paper integrates the theory with Rushton’s r-K theory of race differences.
We reanalyze previously published data on 309 MZ and 333 DZ twin pairs aged 25 to 74 years from the MIDUS survey, a nationally representative archived sample, to examine how much of the genetic covariance between a general factor of personality (GFP), a lower-order life history factor, and a general physical and mental health factor, is of the nonadditive variety. We found nonadditive genetic effects (D) could not be ruled out as a contributor to the shared variance of these three latent factors to a Super-K Life History factor. We suggest these genetic correlations support the view that a slow (K-selected) life history strategy, good health, and the GFP coevolved and are mutually coadapted through directional selection.
Racial and ethnic variations in serum testosterone levels were investigated among a large sample of male Vietnam era veterans. Based on geometric means, significant average differences were found between 3,654 non-Hispanic white and 525 black individuals. The geometric mean for testosterone levels among 200 Hispanic individuals was similar to that of non-Hispanic white individuals. Regarding two other racial/ethnic groups (Asian/Pacific Islanders and Native Americans), no significant differences were found, due perhaps to small sample sizes. Results were interpreted as having considerable potential for explaining some of the race differences in the incidences of cardiovascular diseases, hypertension, and prostate cancer.
Reviews Patterns of Sexual Behavior (see record 1951-07882-000) by C. S. Ford and F. A. Beach. The reviewer notes that this book presents sex in cultural and evolutionary perspective. In one brief volume, the authors have summarized the major facts of mammalian sexual behavior, have laid the groundwork for future scientific studies and theories of sexual behavior, and have spelled out what the layman ought to know about sex. The main scientific problem that Ford and Beach face is to determine which aspects of man's sexual behavior are the product of experience and training and which are determined by his physiological makeup. To accomplish this end, the authors evaluate sexual behavior in American society from the cross-cultural and comparative or evolutionary points of view. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Differential K Theory is proposed to help systematize individual and group differences in life histories, social behaviour and physiological functioning. K refers to one end of a continuum of reproductive strategies organisms can adopt, characterized by the production of very few offspring with a large investment of energy in each. At the opposite extreme is the r-strategy in which organisms produce a large number of offspring but invest little energy in any one. Between-species comparisons demonstrate that these reproductive strategies correlate with a variety of life history traits including: litter size, birth-spacing, parental care, infant mortality, developmental precocity, life span, intelligence, social organization and altruism. As a species, humans are at the K end of the continuum. Some people, however, are postulated to be more K than others. The more K a person is, the more likely he or she is to come from a smaller sized family, with a greater spacing of births, a lower incidence of DZ twinning, and more intensive parental care. Moreover, he or she will tend to be intelligent, altruistic, law-abiding, behaviourally restrained, maturationally delayed, lower in sex drive and longer lived. Thus diverse organismic characteristics, not otherwise relatable, are presumed to covary along the K dimension. Group differences are also hypothesized, such that, in terms of K: higher socio-economic > lower socio-economic; and Mongoloids > Caucasoids > Negroids.
In 50 U.S. states, we found a positive manifold across 11 measures including IQ, skin color, birth rate, infant mortality, life expectancy, HIV/AIDS, violent crime, and state income with the first principal component accounting for 33% of the variance (median factor loading=.34). The correlation with a composite of total violent crime was higher with skin color (r=.55), a more biologically influenced variable than with GDP (r=−.17), a more culturally influenced variable. These results corroborate and extend those found at the international level using INTERPOL crime statistics and at the county, provincial, and state levels within countries using local statistics. We interpret the cross-cultural consistency from an evolutionary life history perspective in which hierarchically organized traits culminate in a single, heritable, super-factor. Traits need to be genetically organized to meet the trials of life—survival, growth, and reproduction. We discuss brain size and the g nexus as central to understand individual and group differences and we highlight melanin and skin color as a potentially important new life history variable.
Although body coloration is often used in social interactions, few studies have tested whether it is linked to a suite of behavioural traits. We examined whether among captive adult male eastern Hermann’s tortoises, Eurotestudo boettgeri, behavioural patterns covary with eumelanic coloration of the shell. Dark eumelanic males were more aggressive in male–male confrontations and bolder towards humans. These relationships were independent of body size and ambient temperature. Activity level and exploration were not significantly associated with coloration. We conclude that, at least in captivity, melanic shell coloration predicts agonistic behaviour towards conspecifics and fearfulness towards humans (i.e. boldness).
The critique by Wicherts, Borsboom, and Dolan misses the Big Picture provided by Richard Lynn in assembling national IQs and by J. Philippe Rushton in developing an evolutionary life history theory of race differences in brain size and intelligence. Their perspectives seem correct in essentials although may prove wrong in particulars. I provide evidence in their favor and also defend my own research on the importance of skin color as a correlate of IQ.
An r-selected approach to reproduction emphasizes producing large numbers of offspring with minimal care given to each offspring by its parents. At the other end of the continuum, K-selection is an approach in which few offspring are produced, but maximal care is taken to insure reproductive viability of each offspring. This article argues that several heretofore seemingly unrelated factors which have been found associated with serious victimful criminal behavior (i.e. serious violent and property offenses) in numerous countries are predictable by hypothesizing that criminal behavior is part of an r-selected approach to reproduction.
A large number of national and geographic population samples were used to test the hypothesis that the variation in mean values of skin color in the diverse populations are consistently correlated with the mean measured or estimated IQs of the various groups, as are some other physical variables, known as an ecological correlation. Straightforward statistical analyses clearly bear out the hypothesis, showing a significant positive ecological correlation between lightness of mean skin color and mean IQ across different populations. The main limitation of such a study design is that correlations obtained from this type of analysis are completely non-informative regarding any causal or functional connection between individual differences in skin pigmentation and and individual differences in IQ, nor are they informative regarding the causal basis of the correlation, e.g., simple genetic association due to cross-assortative mating for skin color and IQ versus a pleiotropic correlation in which both of the phenotypically distinct but correlated traits are manifested by one and the same gene.
At an experimental farm in Novosibirsk, Siberia, geneticists have been
working for four decades to turn foxes into dogs. They are not trying to
create the next pet craze. Instead, author Trut and her predecessors
hope to explain why domesticated animals such as pigs, cattle and dogs
are so different from their wild ancestors. Selective breeding alone
cannot explain all the differences. Trut's mentor, the eminent Russian
geneticist Dmitri Belyaev, thought that the answers lay in the process
of domestication itself, which might have dramatically changed wolves'
appearance and behavior even in the absence of selective breeding. To
test his hypothesis, Belyaev and his successors at the Institute have
been breeding another canine species, silver foxes, for a single trait:
friendliness toward people. Although no one would mistake them for dogs,
the Siberian foxes appear to be on the same overall evolutionary
path—a route that other domesticated animals also may have
followed while coming in from the wild.
A single common factor underlies variation in delinquent acts; thus, by statistical criteria, they appear “unitary.” We extended the analysis of single-factoredness from delinquency itself to explanatory variables associated with delinquency (e.g., parental affection, personality traits, school involvement). Three factors were extracted from 15 explanatory variables. All three factors were statistically associated with delinquency, but the first factor extracted dominated in terms of variance explained (21.6% vs. 1.6% and 3.4%, respectively). This first factor had loadings from variables in conceptually diverse domains (e.g., family and peer relations, school success, and personality). A question for delinquency theory is why diverse explanatory variables load primarily on one factor, if theories postulate multiple and complex social and individual influences.
Humans skin is the most visible aspect of the human phenotype. It is distinguished mainly by its naked appearance, greatly enhanced abilities to dissipate body heat through sweating, and the great range of genetically determined skin colors present within a single species. Many aspects of the evolution of human skin and skin color can be reconstructed using comparative anatomy, physiology, and genomics. Enhancement of thermal sweating was a key innovation in human evolution that allowed maintenance of homeostasis (including constant brain temperature) during sustained physical activity in hot environments. Dark skin evolved pari passu with the loss of body hair and was the original state for the genus Homo. Melanin pigmentation is adaptive and has been maintained by natural selection. Because of its evolutionary lability, skin color phenotype is useless as a unique marker of genetic identity. In recent prehistory, humans became adept at protecting themselves from the environment through clothing and shelter, thus reducing the scope for the action of natural selection on human skin.
This book starts with the 'hypothesis' that differences in IQ are (partly) responsible for differences in national wealth around the world. It ends with the claim that the gap between rich and poor 'will be impossible to eradicate' (p 195). In between is a remarkable creation and moulding of data to show the statistical correlation the hypothesis requires. But there is circularity in the whole exercise.
Analyzed the correlation of nonsexual deviance and physical, sexual behavior using a sibling design. Hypothesized that both types of behavior are partly determined by a latent trait of deviance proneness,
d. In two separate studies—one based on an Oklahoma dataset of college students and their siblings, and the other, on the Adolescent Sexuality Project ({adsex}) dataset of high-school students and their siblings in Tallahassee, Florida—found a strong relationship between relatively early sexual intimacy and nonsexual forms of deviance. Siblings were more alike than chance in deviance and in physical sexual behavior. Most critical for the model, there was also an association between one sibling's sexual intimacy with a partner and the other's deviance. Using {lisrel}, tested the latent-trait model statistically and accepted it as consistent with the obtained correlations. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The culture-only (0% genetic-100% environmental) and the hereditarian (50% genetic-50% environmental) models of the causes of mean Black-White differences in cognitive ability are compared and contrasted across 10 categories of evidence: the worldwide distribution of test scores, g factor of mental ability, heritability, brain size and cognitive ability, transracial adoption, racial admixture, regression, related life-history traits, human origins research, and hypothesized environmental variables. The new evidence reviewed here points to some genetic component in Black-White differences in mean IQ. The implication for public policy is that the discrimination model (i.e., Black-White differences in socially valued outcomes will be equal barring discrimination) must be tempered by a distributional model (i.e., Black-White outcomes reflect underlying group characteristics). (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Rushton's theory of r-K race differences was examined in relation to the rate of murder, rape, and serious assault per 100,000 population and Gross Domestic Product per Person for 74 countries from the 1993–1996 International Crime Statistics published by INTERPOL and the 1999 CIA World Fact Book. Each country was assigned to one of the three macro-races East Asian, European, and African. The results corroborated earlier findings that violent crime is lowest in East Asian countries, intermediate in European countries, and highest in African and in Black Caribbean countries. The median number of violent crimes per 100,000 population were: 7 East Asian countries—34; 45 European countries—42; and 22 African and Black Caribbean countries—149, respectively. The median Gross Domestic Product per Person was highest in East Asian countries (12,600), intermediate in European countries (12,600), intermediate in European countries (7,400), and lowest in African and Black Caribbean countries ($1,900). Across the three population groups there was an ecological correlation of –.96 between crime and wealth (wealthier countries had less crime). Finer-grained analyses, however, found that while wealth was negatively related to crime across European or East Asian countries, it was positively related to crime for the African and Black Caribbean countries (i.e., the wealthier an African or Black Caribbean country, the greater its rate of violent crime). Future research needs to examine genetic factors in addition to cultural factors as well as their interactions.
Mean levels of three characteristics—verbal IQ, number of sexual partners, and birth weight—were examined in African American, White (European-descent) Americans, and Black/White mixed race American adolescents. The sample came from Wave 1 of the National Longitudinal Study of Adolescent Health. The mean age was 16 years. According to their interviewers, the mixed race children had an African American physical appearance. The African American adolescents had a lower birth weight, a lower verbal IQ, and a higher number of sexual partners than did White adolescents. For each characteristic, the mixed race mean fell between the means of the two parental populations. Design extensions were proposed that include: (1) directly genotyping for individual racial admixture, (2) including parents of the mixed race children, and (3) including their cousins.
The present study examines predictions from Rushton’s differential K theory that diverse traits covary with intelligence, reproductive strategies, speed of maturation, parental care, and longevity. The predictions are tested by inter-correlating 129 cross-national differences in IQ, birth rate, infant mortality, HIV/AIDS, and life expectancy. A K super-factor accounted for 75% of the variance. Moreover, the correlations were significantly higher with skin color, a biological variable, than they were with gross domestic product (GDP), a culturally influenced variable. The median of the 21 inter-correlations among the seven variables was 0.68.
Following our earlier paper on race differences in sexual behavior (J. P. Rushton & A. F. Bogaert, 1987, Journal of Research in Personality, 21, 529–551), we analyze additional data from the Institute for Sex Research which indicates that in terms of sexual restraint, college-educated whites non-college-educated whites college-educated blacks on measures such as speed of occurrence of premarital, marital, and extramarital sexual experiences, number of sexual partners, frequency of intercourse, speed and incidence of pregnancy, and rapidity of the menstrual cycle. As such, the data suggest that race may be a more powerful predictor of sexual behavior than educational level or social class. This ordering was predicted from a gene-based evolutionary theory of reproductive strategies in which a trade-off occurs between gamete production and social behaviors such as intelligence, law-abidingness, and parental care.
National differences in murder, rape, and serious assault were examined in 113 countries in relation to national IQ, income, skin color, birth rate, life expectancy, infant mortality, and HIV/AIDS. Data were collated from the 1993–1996 International Crime Statistics published by INTERPOL. Violent crime was found to be lower in countries with higher IQs, higher life expectancies, lighter skin color, and lower rates of HIV/AIDS, although not with higher national incomes or higher rates of infant mortality. A principal components analysis found the first general factor accounted for 52% of the variance. Moreover, the correlations were significantly higher with skin color, a more biologically influenced variable, than with measures of national income, a more culturally influenced variable. When the 19 sub-Saharan African countries were excluded from analysis the crime/IQ relation held but the crime/skin color relation did not.
The impetus for our study was the contention of both Lynn [Lynn, R. (1991) Race differences in intelligence: A global perspective. Mankind Quarterly, 31, 255–296] and Rushton (Rushton [Rushton, J. P. (1995). Race, evolution and behavior: A life history perspective. New Brunswick, NJ: Transaction; Rushton, J. P. (1997). Race, intelligence, and the brain: The errors and omissions of the revised edition of S.J. Gould's the mismeasurement of man. Personality and Individual Differences, 23, 169–180; Rushton, J. P. (2000). Race, evolution, and behavior. A life history perspective (3rd edition). Port Huron: Charles Darwin Research Institute] that persons in colder climates tend to have higher IQs than persons in warmer climates. We correlated mean IQ of 129 countries with per capita income, skin color, and winter and summer temperatures, conceptualizing skin color as a multigenerational reflection of climate. The highest correlations were − 0.92 (rho = − 0.91) for skin color, − 0.76 (rho = − 0.76) for mean high winter temperature, − 0.66 (rho = − 0.68) for mean low winter temperature, and 0.63 (rho = 0.74) for real gross domestic product per capita. The correlations with population of country controlled for are almost identical. Our findings provide strong support for the observation of Lynn and of Rushton that persons in colder climates tend to have higher IQs. These findings could also be viewed as congruent with, although not providing unequivocal evidence for, the contention that higher intelligence evolves in colder climates. The finding of higher IQ in Eurasians than Africans could also be viewed as congruent with the position of Diamond (1997) that knowledge and resources are transmitted more readily on the Eurasian west–east axis.
First, I describe why intelligence (Spearman's g) can only be fully understood through r–K theory, which places it into an evolutionary framework along with brain size, longevity, maturation speed, and several other life-history traits. The r–K formulation explains why IQ predicts longevity and also why the gap in mortality rates between rich and poor has increased with greater access to health care. Next, I illustrate the power of this approach by analyzing a large data set of life-history variables on 234 mammalian species and find that brain size correlates r=.70 with longevity (.59, after controlling for body weight and body length). A principal component analysis reveals a single r–K life-history factor with loadings such as: brain weight (.85), longevity (.91), gestation time (.86), birth weight (.62), litter size (−.54), age at first mating (.73), duration of lactation (.67), body weight (.61), and body length (.63). The factor loadings remain high when body weight and length are covaried. Finally, I demonstrate the theoretical importance of this approach in restoring the concept of “progress” to its proper place in evolutionary biology showing why, over the last 575 million years of evolutionary competition of finding and filling new niches, there has always been (and likely always will be) “room at the top.”
Population differences exist in personality and sexual behavior such that, in terms of restraint, Orientals > whites > blacks. This ordering is predicted from an evolutionary theory of reproductive strategies in which a tradeoff occurs between gamete production and parental care. Literature is reviewed on differences between the three groups in rate of ovulation, intercourse frequencies, sexual attitudes, developmental precocity, size of genitalia, secondary sexual characteristics, and biologic control of behavior that accord with this formulation. Novel analyses of data from the Institute for Sex Research are also carried out, indicating that American blacks, compared to American whites, are more precocious and less restrained. Their parents were younger when they were born, had more children, and had an earlier mortality. Blacks left home earlier, experienced a variety of premarital, marital, and extramarital sexual events earlier, had a greater number of premarital and extramarital partners, had a greater frequency of marital intercourse, used fewer contraceptives, and had a greater incidence of pregnancy, at a faster rate. The men had larger penises, at a different angle of erection, and maintained intromission longer, while the women had shorter menstrual cycles, more periodicity of sexual response, and a greater number of orgasms per act of coitus. Whites varied their sexual activity more, both with spouses and with prostitutes, although blacks consorted with prostitutes more frequently. Finally, blacks had a shorter duration of marriage and more permissive sexual attitudes.
In vertebrates, melanin-based coloration is often associated with variation in physiological and behavioural traits. We propose that this association stems from pleiotropic effects of the genes regulating the synthesis of brown to black eumelanin. The most important regulators are the melanocortin 1 receptor and its ligands, the melanocortin agonists and the agouti-signalling protein antagonist. On the basis of the physiological and behavioural functions of the melanocortins, we predict five categories of traits correlated with melanin-based coloration. A review of the literature indeed reveals that, as predicted, darker wild vertebrates are more aggressive, sexually active and resistant to stress than lighter individuals. Pleiotropic effects of the melanocortins might thus account for the widespread covariance between melanin-based coloration and other phenotypic traits in vertebrates.
The melanocortin system is implicated in the expression of many phenotypic traits. Activation of the melanocortin MC(1) receptor by melanocortin hormones induces the production of brown/black eumelanic pigments, while activation of the four other melanocortin receptors affects other physiological and behavioural functions including stress response, energy homeostasis, anti-inflammatory and sexual activity, aggressiveness and resistance to oxidative stress. We recently proposed the hypothesis that some melanocortin-physiological and -behavioural traits are correlated within individuals. This hypothesis predicts that the degree of eumelanin production may, in some cases, be associated with the regulation of glucocorticoids, immunity, resistance to oxidative stress, energy homeostasis, sexual activity, and aggressiveness. A review of the zoological literature and detailed experimental studies in a free-living population of barn owls (Tyto alba) showed that indeed melanic coloration is often correlated with the predicted physiological and behavioural traits. Support for predictions of the hypothesis that covariations between coloration and other phenotypic traits stem from pleiotropic effects of the melanocortin system raises a number of theoretical and empirical issues from evolutionary and pharmacological point of views.
Using symbols from population biology, a continuum of reproductive strategies can be distinguished ranging from r, the production of large numbers of offspring provided with minimal care, to K, the production of few offspring nurtured intensively. While all humans are at the K end of the continuum, some are proposed to be more so than others. If multiple egg production is part of an r-reproductive strategy, certain facts may be ordered. Compared to mothers of singletons, for example, mothers of DZ twins have a lower age of menarche, a shorter menstrual cycle, a higher number of marriages, a higher rate of coitus, more illegitimate children, a closer spacing of births, a greater fecundity, more wasted pregnancies, a larger family, an earlier menopause, and an earlier mortality. Further, all twins have a shorter gestation period, a lower birth weight, and a greater incidence of infant mortality, with DZ twins having a greater frequency of health disorders, a higher mortality rate, and a lower rate of enrollment in volunteer registries. Multiple birthing also occurs more frequently in families of lower than of higher social status, and in those of African than of European and especially than of Oriental descent.
Selection of wild gray rats for domestication (tame behavior) resulted in a sharp increase in the frequency of heterozygotes at the h allele of hooded, the main locus of rat depigmentation. The observed effect of the selection on the manifestation of the h allele is compared with similar effects giving rise to piebaldness in other animals subjected to experimental domestication. The results are discussed in terms of genetic specificity of piebaldness and of the selection vector.
Skin color is one of the most conspicuous ways in which humans vary and has been widely used to define human races. Here we present new evidence indicating that variations in skin color are adaptive, and are related to the regulation of ultraviolet (UV) radiation penetration in the integument and its direct and indirect effects on fitness. Using remotely sensed data on UV radiation levels, hypotheses concerning the distribution of the skin colors of indigenous peoples relative to UV levels were tested quantitatively in this study for the first time.
The melanocortin system consists of melanocortin peptides derived from the proopiomelanocortin gene, five melanocortin receptors, two endogenous antagonists, and two ancillary proteins. This review provides an abbreviated account of the basic biochemistry, pharmacology, and physiology of the melanocortin system and highlights progress made in four areas. In particular, recent pharmacological and genetic studies have affirmed the role of melanocortins in pigmentation, inflammation, energy homeostasis, and sexual function. Development of selective agonists and antagonists is expected to further facilitate the investigation of these complex physiological functions and provide an experimental basis for new pharmacotherapies.
Accelerating evolution
- Belyaev
Belyaev, D. K., & Trut, L. N. (1982). Accelerating evolution. Science in the USSR, 5(24– 29), 60–64
Kim The hooded allele and selection of wild Norway rats Rattus norvegicus for behavior Genetika
- Trut
- Trut