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.