Samstag, 30. August 2014

The Importance of Intraindividual Variation in Reaction Time

The Importance  of Intraindividual Variation in Reaction Time
Arthur R. Jensen (1992)


Individual differences in the trial-to-trial variability of reaction time (RT), indexed by the standard deviation of the individual's RTs over n trials (RTSD), generally has a larger negative correlation with psychometric g than does the median RT (RTmd) over n trials. Large data sets are brought to bear on the question of whether RTmd and RTSD, which are highly correlated, reflect one and the same source of variance, but with different reliability and validity for predicting g, or represent independent processes. Several lines of evidence consistently lead to the conclusion that RTmd and RTSD, though having a substantial proportion of their variance in common even when measured separately in experimentally independent sets of RT trials, also have significant independent components of variance, each of which is correlated with psychometric g. Hypotheses about the neurophysiological basis of individual differences in the independent components of RTmd and RTSD are discussed.

[It's likely that RTSD reflects "neural noise" and that individual intelligence differences are partly caused by individual differences in "neural noise".]

Freitag, 29. August 2014

Relation of spacial ability to testosterone levels in men and women

>The correlation between T levels and spatial ability is not linear. That is, abilities do not simply increase, pari passu, with T levels. Rather, among normal men, those with higher T levels actually perform worse than those with lower levels (see figure 9-6). This fact is consistent with observations of CAH males. CAH males experience higher androgen levels prenatally than healthy males, but their spatial ability is not enhanced. In fact, some studies report that performance is poorer than in unaffected men. Studies in rats also find that excess testosterone during early development diminishes rather than augments masculinization. 

Among normal women, whose base level of T is low, those with higher T levels perform better on spatial tasks than those with lower levels (figure 9-6). Again, this is consistent with the findings from CAH girls, in that pre-natal exposure to higher levels of T generally enhances spatial ability. It appears, therefore, that superior spatial ability is associated with an optimal level of T, neither too low nor too high, apparently in the lower range of normal Caucasian males. (We have no equivalent information for non-Caucasians.) Other abilities investigated to date appear not to be strongly associated with T levels. However, recall that male infants who make the least eye contact, and differ most in this trait from female infants, were exposed prenatally to T levels at the low end of the male range.  Those exposed to T levels at the high end of the male range were more similar to females in making more eye contact.<

Women, Men, and the Sciences [The Science on Women and Science] - p. 237-238
Jerre Levy & Doreen Kimura (2009)

[Charles Murray wrote the book's conclusion.]

Mittwoch, 27. August 2014

Smart Fractions/Creative Minorities & High Culture:

>The social implications of exceptionally high ability and its interaction with the other factors that make for unusual achievements are considerably greater than the per­sonal implications. The quality of a society’s culture is highly determined by the very small fraction of its population that is most exceptionally endowed. The growth of civili­zation, the development of written language and of mathematics, the great religious and philosophic insights, scientific discoveries, practical inventions, industrial developments, advancements in legal and political systems, and the world’s masterpieces of literature, architecture, music and painting, it seems safe to say, are attributable to a rare small proportion of the human population throughout history who undoubtedly possessed, in addition to other important qualities of talent, energy, and imagination, a high level of the essential mental ability measured by tests of intelligence.<

Arthur R. Jensen (1980)

Rotherham Child Abuse Scandal

HBD Chick:
>Stop creating a climate of fear!<

Dr. James Thompson:
>Rotherham Child Abuse Scandal<

Dennis Mangan:

Dienstag, 26. August 2014

Women's Representation in 60 Occupations from 1972 to 2010: More Women in High-Status Jobs, Few Women in Things-Oriented Jobs

Women's Representation in 60 Occupations from 1972 to 2010: More Women in High-Status Jobs, Few Women in Things-Oriented Jobs -> pdf
Richard A. Lippa, Kathleen Preston, John Penner (2014)


To explore factors associated with occupational sex segregation in the United States over the past four decades, we analyzed U.S. Bureau of Labor Statistics data for the percent of women employed in 60 varied occupations from 1972 to 2010. Occupations were assessed on status, people-things orientation, and data-ideas orientation. Multilevel linear modeling (MLM) analyses showed that women increasingly entered high-status occupations from 1972 to 2010, but women's participation in things-oriented occupations (e.g., STEM fields and mechanical and construction trades) remained low and relatively stable. Occupations' data-ideas orientation was not consistently related to sex segregation. Because of women's increased participation in high-status occupations, occupational status became an increasingly weak predictor of women's participation rates in occupations, whereas occupations' people-things orientation became an increasingly strong predictor over time. These findings are discussed in relation to theories of occupational sex segregation and social policies to reduce occupational sex segregation.

Montag, 25. August 2014

Feminist activist women are masculinized in terms of digit-ratio and dominance: A possible explanation for the feminist paradox

Feminist activist women are masculinized in terms of digit-ratio and dominance: A possible explanation for the feminist paradox
Guy Madison, Ulrika Aasa, John Wallert and Michael Woodley (2014)


The feminist movement purports to improve conditions for women, and yet only a minority of women in modern societies self-identify as feminists. This is known as the feminist paradox. It has been suggested that feminists exhibit both physiological and psychological characteristics associated with heightened masculinization, which may predispose women for heightened competitiveness, sex-atypical behaviors, and belief in the interchangeability of sex roles. If feminist activists, i.e. those that manufacture the public image of feminism, are indeed masculinized relative to women in general, this might explain why the views and preferences of these two groups are at variance with each other. We measured the 2D:4D digit ratios (collected from both hands) and a personality trait known as dominance (measured with the Directiveness scale) in a sample of women attending a feminist conference. The sample exhibited significantly more masculine 2D:4D and higher dominance ratings than comparison samples representative of women in general, and these variables were furthermore positively correlated for both hands. The feminist paradox might thus to some extent be explained by biological differences between women in general and the activist women who formulate the feminist agenda.

A greater decline in female facial attractiveness during middle age reflects women’s loss of reproductive value

A greater decline in female facial attractiveness during middle age reflects women’s loss of reproductive value
Dario Maestripieri, Amanda C. E. Klimczuk, Daniel M. Traficonte and M. Claire Wilson (2014)


Facial attractiveness represents an important component of an individual’s overall attractiveness as a potential mating partner. Perceptions of facial attractiveness are expected to vary with age related changes in health, reproductive value, and power. In this study, we investigated perceptions of facial attractiveness, power, and personality in two groups of women of pre- and post-menopausal ages (35–50 years and 51–65 years, respectively) and two corresponding groups of men. We tested three hypotheses: (1) that perceived facial attractiveness would be lower for older than for younger men and women; (2) that the age-related reduction in facial attractiveness would be greater for women than for men; and (3) that for men, there would be a larger increase in perceived power at older ages. Eighty facial stimuli were rated by 60 (30 male, 30 female) middle-aged women and men using online surveys. Our three main hypotheses were supported by the data. Consistent with sex differences in mating strategies, the greater age-related decline in female facial attractiveness was driven by male respondents, while the greater age-related increase in male perceived power was driven by female respondents. In addition, we found evidence that some personality ratings were correlated with perceived attractiveness and power ratings. The results of this study are consistent with evolutionary theory and with previous research showing that faces can provide important information about characteristics that men and women value in a potential mating partner such as their health, reproductive value, and power or possession of resources.

Everyday Life as an Intelligence/Personality Test

(A) Everyday Life as an Intelligence Test

"Every semantic discrimination, every decision, every choice-point, every challenge, every opportunity for performance in everyday life has some degree of g loading, however slight it may be." Arthur R. Jensen

(B) Everyday Life as a Personality/Willpower Test

~Every decision, every choice-point, every challenge, every opportunity for performance in everyday life has some degree of "p"/"w" loading, however slight it may be.

[Perhaps also the second point makes sense...]

Sonntag, 24. August 2014

Giftedness and Genius: Crucial Differences

Giftedness and Genius: Crucial Differences
Arthur R. Jensen (1996)

Task Complexity and the Speed and Efficiency of Elemental Information Processing: Another Look at the Nature of Intellectual Giftedness

"According to much contemporary research and theory in human information-processing, the main difference between intellectually gifted and normal individuals is the effectiveness of higher-order or metacognitive processes ... . A relatively minor role is attributed to differences in the lower-order cognitive processes (e.g., encoding, short-term memory scanning, and retrieval of information from long-term memory) that un­derlie all thought and action and are orchestrated by the metacognitive processes ... . A considerable amount of recent evidence, however, suggests that ele­mental information-processing abilities may be more importantly related to intellectual giftedness than previously considered ......

J. H. Kranzler, P. H. Wang & A. R. Jensen (1994)

Samstag, 23. August 2014

Understanding g in Terms of Information Processing

Understanding g in Terms of Information Processing
Arthur R. Jensen (1992)


Psychometric g, the general factor in individual differences in all types of tests and performances involving any mental ability, has much wider importance and implications than are encompassed by the field of psychometrics. It is argued that the nature of g must be understood in terms of information processes rather than in terms of the specific knowledge and skills that are seen in the content of conventional mental tests. The wide range of individual differences in g and disparities in the distribution of g in different subpopulations have important implications for understanding some of the major problems confronting public education.

[See also: Arthur Robert Jensen memorial site]

Early life expenditure in sexual competition is associated with increased reproductive senescence in male red deer

Early life expenditure in sexual competition is associated with increased reproductive senescence in male red deer 
Jean-François Lemaître, Jean-Michel Gaillard, Josephine M. Pemberton, Tim H. Clutton-Brock and Daniel H. Nussey (2014)
Proceedings of the Royal Society B: Biological Sciences


The evolutionary theories of senescence predict that investment in reproduction in early life should come at the cost of reduced somatic maintenance, and thus earlier or more rapid senescence. There is now growing support for such trade-offs in wild vertebrates, but these exclusively come from females. Here, we test this prediction in male red deer (Cervus elaphus) using detailed longitudinal data collected over a 40-year field study. We show that males which had larger harems and thereby allocated more resources to reproduction during early adulthood experienced higher rates of senescence in both harem size and rut duration. Males that carried antlers with more points during early life did not show more pronounced declines in reproductive traits in later life. Overall, we demonstrate that sexual competition shapes male reproductive senescence in wild red deer populations and provide rare empirical support for the disposable soma theory of ageing in males of polygynous vertebrate species.


"[Although] high reproductive expenditure in early adulthood is associated with an increased rate of decline in late life, this decline is not sufficient to negate the phenotypic superiority of these males until extreme old age."


Ethnic Nepotism as a Cross-Cultural Background Factor of Ethnic Conflicts

Ethnic Nepotism as a Cross-Cultural Background Factor of Ethnic Conflicts
Tatu Vanhanen (2014)


The purpose of this article has been to explore why ethnic conflicts tend to break out in all ethnically divided societies. The principal explanation was traced to the evolved disposition for ethnic nepotism shared by all human populations. Ethnic nepotism was measured roughly by the degree of ethnic heterogeneity of the populations. It was correlated with the scale of ethnic conflicts in the group of 187 countries. The results of correlation analysis indicate that ethnic heterogeneity explains 55% of the variation in the scale of ethnic conflicts, and the results of regression analysis disclose that the same relationship more or less applies to all 187 countries. These results led to the conclusion that ethnic nepotism is the common cross-cultural background factor which supports the persistence of ethnic conflicts in the world as long as there are ethnically divided societies.

Freitag, 22. August 2014

Perceived facial adiposity conveys information about women’s health

Perceived facial adiposity conveys information about women’s health (full download)
Rowan M. Tinlin, Christopher D. Watkins, Lisa L. M. Welling, Lisa M. DeBruine, Emad A. S. Al-Dujaili, and Benedict C. Jones (2012)


Although several prominent theories of human facial attractiveness propose that some facial characteristics convey information about people’s health, empirical evidence for this claim is somewhat mixed. While most previous research into this issue has focused on facial characteristics such as symmetry, averageness, and sexual dimorphism, a recent study reported that ratings of facial adiposity (i.e., perceptions of fatness in the face) were positively correlated with indices of poor physical condition in a sample of young adults (i.e., reported past health problems and measures of cardiovascular fitness). These findings are noteworthy, since they suggest that perceived adiposity is a potentially important facial cue of health that has been overlooked by much of the previous work in this area. Here, we show that ratings of young adult women’s facial adiposity are (1) better predicted by their body weight than by their body shape (Studies 1 and 2), (2) correlated with a composite measure of their physical and psychological condition (Study 2), and (3) negatively correlated with their trait (i.e., average) salivary progesterone levels (Study 3). Together, these findings present further evidence that perceived facial adiposity, or a correlate thereof, conveys potentially important information about women’s actual health.

Donnerstag, 21. August 2014

Women’s physical and psychological condition independently predict their preference for apparent health in faces

Women’s physical and psychological condition independently predict their preference for apparent health in faces 
Benedict Christopher Jones, Anthony C. Little, Lynda Boothroyd, David R. Feinberg, R. Elisabeth Cornwell, Lisa M. DeBruine, S. Craig Roberts, Ian S. Penton-Voak, Miriam J. Law Smith, Fhionna R. Moore, Hasker P. Davis, David I. Perrett (2005)


Physical condition (e.g., health, fertility) influences female mate preferences in many species, with females in good condition preferring "higher quality" (e.g., healthier) mates. In humans, condition may comprise both physical (e.g., health and fertility) and psychological factors (e.g., stress, anxiety, and depression). We found that women with low waist-to-hip ratios (indicating health and fertility) or who scored low on anxiety, depression, and stress measures expressed greater attraction to composite male (but not female) faces with color and texture cues associated with apparent health than did women with relatively high waist-to-hip ratios or who scored relatively high on the anxiety, depression, and stress measures. These effects of physical and psychological condition were independent and were not mediated by women’s perceptions of their own attractiveness. Our findings indicate that women’s physical and psychological conditions both contribute to individual differences in face preferences.

Sonntag, 17. August 2014

Vocal modulation during courtship increases proceptivity even in naive listeners

Vocal modulation during courtship increases proceptivity even in naive listeners
Juan David Leongómez, Jakub Binter, Lydie Kubicová, Petra Stolařová, Kateřina Klapilová, Jan Havlíček, S. Craig Roberts (2014)


Speakers modulate their voice when talking to infants, but we know little about subtle variation in acoustic parameters during speech in adult social interactions. Because tests of perception of such variation are hampered by listeners’ understanding of semantic content, studies often confine speech to enunciation of standard sentences, restricting ecological validity. Furthermore, apparent paralinguistic modulation in one language may be underpinned by specific parameters of that language. Here we circumvent these problems by recording speech directed to attractive or unattractive potential partners or competitors, and testing responses to these recordings by naive listeners, across both a Germanic (English) and a Slavic (Czech) language. Analysis of acoustic parameters indicates that men’s voices varied F0 most in speech towards potential attractive versus unattractive mates, while modulation of women’s F0 variability was more sensitive to competitors, with higher variability when those competitors were relatively attractive. There was striking similarity in patterns of social context-dependent F0 variation across the two model languages, with both men’s and women’s voices varying most when responding to attractive individuals. Men’s minimum pitch was lower when responding to attractive than unattractive women. For vocal modulation to be effective, however, it must be sufficiently detectable to promote proceptivity towards the speaker. We showed that speech directed towards attractive individuals was preferred by naive listeners of either language over speech by the same speaker to unattractive individuals, even when voices were stripped of several acoustic properties by low-pass filtering, which renders speech unintelligible. Our results suggest that modulating F0 may be a critical parameter in human courtship, independently of semantic content.

Partner Choice, Relationship Satisfaction, and Oral Contraception: The Congruency Hypothesis

Partner Choice, Relationship Satisfaction, and Oral Contraception: The Congruency Hypothesis
S. Craig Roberts, Anthony C. Little, Robert P. Burriss, Kelly D. Cobey, Kateřina Klapilová, Jan Havlíček, Benedict C. Jones, Lisa DeBruine, and Marion Petrie (2014)


Hormonal fluctuation across the menstrual cycle explains temporal variation in women’s judgment of the attractiveness of members of the opposite sex. Use of hormonal contraceptives could therefore influence both initial partner choice and, if contraceptive use subsequently changes, intrapair dynamics. Associations between hormonal contraceptive use and relationship satisfaction may thus be best understood by considering whether current use is congruent with use when relationships formed, rather than by considering current use alone. In the study reported here, we tested this congruency hypothesis in a survey of 365 couples. Controlling for potential confounds (including relationship duration, age, parenthood, and income), we found that congruency in current and previous hormonal contraceptive use, but not current use alone, predicted women’s sexual satisfaction with their partners. Congruency was not associated with women’s nonsexual satisfaction or with the satisfaction of their male partners. Our results provide empirical support for the congruency hypothesis and suggest that women’s sexual satisfaction is influenced by changes in partner preference associated with change in hormonal contraceptive use.

Donnerstag, 14. August 2014

Age Differences in Personality Traits From 10 to 65: Big Five Domains and Facets in a Large Cross-Sectional Sample

Age Differences in Personality Traits From 10 to 65: Big Five Domains and Facets in a Large Cross-Sectional Sample (full download)
C. J. Soto, S. D. Gosling, O. P. John, J. Potter (2011)


Hypotheses about mean-level age differences in the Big Five personality domains, as well as 10 more specific facet traits within those domains, were tested in a very large cross-sectional sample (N = 1,267,218) of children, adolescents, and adults (ages 10 – 65) assessed over the World Wide Web. The results supported several conclusions. First, late childhood and adolescence were key periods. Across these years, age trends for some traits (a) were especially pronounced, (b) were in a direction different from the corresponding adult trends, or (c) first indicated the presence of gender differences. Second, there were some negative trends in psychosocial maturity from late childhood into adolescence, whereas adult trends were overwhelmingly in the direction of greater maturity and adjustment. Third, the related but distinguishable facet traits within each broad Big Five domain often showed distinct age trends, highlighting the importance of facet-level research for understanding life span age differences in personality.

[The extraversion graph didn't convince me. Are women really more assertive than men?]

Geographic distribution of significant events in science, technology, mathematics, and medicine from 800 BCE until 1900

[press Ctrl & + to enlarge; full size: click at the image]

Genius in World Civilization
Charles Murray (2014)

Sex differences in face cognition

Sex differences in face cognition  (full download)
W. Sommer, A. Hildebrandt, O. Kunina-Habenicht, A. Schacht, O. Wilhelm (2013)


Although there is abundant evidence for female superiority in Face Cognition (FC), a number of questions regarding sex differences remain to be addressed. Here we report a reanalysis of data on the level of latent factors, modeled on the basis of an extensive test battery applied to three samples of over 800 adults in all. In independent samples the measurement structure of FC was invariant for both sexes, indicating that the measurement of the construct does not depend on the context variable sex, and investigating mean performance differences will not be biased by measurement issues — a neglected aspect in previous studies. We confirmed female superiority for face perception (FP) and face memory (FM). For the first time we could show that these sex differences prevailed after accounting for sex differences in broadly measured general cognitive functioning and in object perception. Across adult age, sex differences in FM increased due to the rapid decline of this ability in men, whereas performance in women remained stable across adult age. Self-reported social involvement and things-oriented activities moderated sex-differences in FM. Results show that sex differences are salient at the level of specific FC constructs and that they can be partially explained by social involvement.

Sex differences in foreign language ability: an evolutionary theory

Sex differences in foreign language ability: an evolutionary theory
Richard Lynn and Davide Piffer (2011) (p 78-87 / 75-84)


Sex differences in foreign language ability are presented for a number of countries. Females consistently achieve better average results than males on foreign language ability in all the countries, and the superiority of girls in foreign languages was generally greater than in their own native language. Females perform better than males in public examinations in foreign languages, and more females than males choose to study foreign languages at school and college. An explanation for the superiority of females in foreign language ability is proposed in terms of evolutionary psychology and anthropology to the effect that females typically moved into neighboring groups in the evolutionary environment, and this gave a selective advantage to females who could acquire a foreign language easily.

Mittwoch, 13. August 2014

Does self-esteem account for the higher-order factors of the Big Five?

Does self-esteem account for the higher-order factors of the Big Five?
Stephen Erdle , Samuel D. Gosling , Jeff Potter (2009)


The purpose of this study was to determine whether higher-order factors of the Big Five personality factors are artifacts of self-esteem. Based on previous research, it was predicted that two higher-order factors, Stability and Plasticity, would emerge from correlations among the Big Five factors. It was also predicted that self-esteem would be related to the higher-order factors but would not account for them. The Big Five and self-esteem were measured in a sample of 628,640 participants using an interactive website on the Internet. Results showed that the two higher-order factors of the Big Five existed and were substantially correlated with self-esteem but remained intact when self-esteem was statistically controlled, indicating that they are not artifacts of self-esteem.

Freitag, 8. August 2014

Quantity and structure of word knowledge across adulthood

Quantity and structure of word knowledge across adulthood
Timothy A. Salthouse (2014)


Cross-sectional and longitudinal comparisons reveal declines in vocabulary knowledge.
Relations among different types of vocabulary tests are weaker at older ages.
Decreases in vocabulary performance may be related to structural changes in knowledge.


Cross-sectional and longitudinal data from moderately large samples of healthy adults confirmed prior findings of age-related declines in measures of the quantity of word knowledge beginning around age 65. Additional analyses were carried out to investigate the interrelations of different types of vocabulary knowledge at various periods in adulthood. Although the organizational structures were similar in adults of different ages, scores on tests with different formats had weaker relations to a higher-order vocabulary construct beginning when adults were in their 60s. The within-person dispersion among different vocabulary test scores was also greater after about 65 years of age. The discovery of quantitative decreases in amount of knowledge occurring at about the same age as qualitative shifts in the structure of knowledge raises the possibility that the two types of changes may be causally linked.

Male-Female Ratio / World's Billionaires versus Self-made Billionaires

Investigating the world's rich and powerful: Education, cognitive ability, and sex differences
Jonathan Wai (Intelligence, 2014)

[See also: Billionaires are smart]

Dienstag, 5. August 2014

Mating Preferences & Racism:

Geoffrey Miller:
>Yeah. It’s a time to experiment, so don’t have tunnel vision about, “Oh, I have to date just the college girls and not the secretaries.” Don’t have tunnel vision about age. You’re allowed to date grad students if they’re into you. And don’t have tunnel vision about ethnicity, either. I had the same thing in college. Like, there were all these Jewish girls who I got along with really well. I’m not Jewish, but the Jewish guys at Columbia were all chasing the blonde Midwestern girls who all seemed new and exciting to them, leaving the Jewish girls neglected. The Jewish girls were really into guys who were smart, and I was kind of smart, and that just worked. If I had preconceptions, like, “Well, I’m kind of white Anglo-Saxon Protestant Midwesterner and I should stick to my people,” that would’ve been just stupid. So, broaden your horizons.<

Tucker Max:
>Not only is it pretty racist, which is ridiculous to begin with, but listen. ...<

[If it is racist to have a mating preference for one's own ethny, it's also sexist to have a mating preference for the other gender. That's nonsense. If you look at the literature about optimal outbreeding you will see that both preferences are adaptive.]

[The people from the Near East may have developed something like an "instinct" for the avoidance of excessive outbreeding. (Which could explain why cousin marriages are so wide spread in the Near East.) In historical times their societies were much more diverse than northwestern European societies. So there were stronger selection pressures against outbreeding tendencies. In comparison, Northwestern Europeans only show a weak tendency to avoid excessive outbreeding, because in historical times those societies were relatively homogeneous. Perhaps from a biological point of view extreme/excessive outbreeding makes as much sense as the marriage of siblings. But while the opportunity for the latter was abundant throughout human history, the opportunity for the former was not.]