[Comment: More on group differences, the secular rise, and g.]
te Nijenhuis, 2012. The Flynn effect, group differences, and g loadings
Flynn effect gains are predominantly driven by environmental factors. Might these factors also be responsible for group differences in intelligence? Group differences in intelligence have been clearly shown to strongly correlate with g loadings. The empirical studies on whether the pattern of Flynn effect gains is the same as the pattern of group differences yield conflicting findings. We present new evidence on the topic using a number of datasets from the US and the Netherlands. Score gains and g loadings showed a small negative average correlation. The general picture is now that there is a small, negative correlation between g loadings and Flynn effect gains. It appears that the Flynn effect and group differences have different causes
[The continuing debate on the malleability of IQ.]
Gallowat and Brinch, 2012. Schooling in adolescence raises IQ scores
Although some scholars maintain that education has little effect on intelligence quotient (IQ) scores, others claim that IQ scores are indeed malleable, primarily through intervention in early child- hood. The causal effect of education on IQ at later ages is often difficult to uncover because analyses based on observational data are plagued by problems of reverse causation and self-selection into further education. We exploit a reform that increased com- pulsory schooling from 7 to 9 y in Norway in the 1960s to estimate the effect of education on IQ. We find that this schooling reform, which primarily affected education in the middle teenage years, had a substantial effect on IQ scores measured at the age of 19 y
[Comment: The continuing debate about why IQ is negatively correlated with various forms of conservatism. Curiously, no one has yet suggested stereotype threat.]
Leeson et al., 2012. Revisiting the link between low verbal intelligence and ideology
We address a series of criticisms, raised by Woodley (2011), of our paper “Cognitive ability, right-wing authoritarianism, and social dominance orientation: A five-year longitudinal study amongst adolescents” (Heaven, Ciarrochi, & Leeson, 2011). We argue that, while Wood- ley (2011) presents some interesting points, his criticisms do not alter our initial interpretation that verbal intelligence influences the individual’s ideological perspective. We also argue that the use of RWA and SDO in our paper is not problematic given that these variables are treated as ideological constructs and not measures of personality. We further challenge the assump- tion that our reported relationship between low IQ and conservative ideology reflects the greater flexibility of intelligent participants in endorsing liberal norms. Finally, as suggested by Woodley, we re-analysed our data using a General Factor of Personality (GFP). The results indicated that in predicting ideology, GFP did not uniquely account for variance above and be- yond that of intelligence, thus failing to support one of the central hypotheses of the cultural- mediation model.
Rindermann et al., 2011. Political orientations, intelligence and education
The social sciences have traditionally assumed that education is a major determinant of citizens’ po- litical orientations and behavior. Several studies have also shown that intelligence has an impact. According to a theory that conceptualizes intelligence as a burgher (middle-class, civil) phenome- non — intelligence should promote civil attitudes, habits and norms like diligence, order and liberty, which in turn nurture cognitive development — political orientations should be related to intelli- gence, with more intelligent individuals tending towards less extreme political orientations. In a Brazilian sample (N=586), individuals were given the Standard Progressive Matrices (SPM) and a questionnaire measuring age, gender, income, education and political orientations. Firstly, intelli- gence has a positive impact on having any political opinion. Among persons with opinions those with the highest IQ’s were found to be politically center-right and centrist respectively. The relation- ship held after correcting for gender, age, education and income. In a path-analysis, only intelligence had a positive impact on political centrality, whereas education promoted orientations that were farther from the center. These results are discussed in the context of results from other studies in different countries and in the context of different theoretical models on the relationship between political attitudes and IQ.
[Comment: More on Life History Strategy.]
McDonald et al., 2011. A life history approach to understanding the Dark Triad
Researchers adopting an evolutionary perspective have conceptualized the Dark Triad as an exploitative interpersonal style reflective of a fast life history strategy. However, not all research has supported this claim. We posit that different elements of the constructs associated with the Dark Triad may reflect different life history strategies. Our results indicate that the measures of the Dark Triad and other indicators of life history strategies form two distinct factors: (1) a fast life strategy factor that includes the impulsive antisociality facet of psychopathy, the entitlement/exploitativeness facet of narcissism, Machiavellianism, unrestricted sociosexuality, and aggression, and (2) a slow life strategy factor that includes the fearless dominance facet of psychopathy and both the leadership/authority and grandiose exhibitionism facets of narcissism. These factors differentially correlate with established measures of life history strategy. These findings add to the literature by clarifying how the Dark Triad fits into a life history framework.
[Comment: Age, heritability, stability.]
Understanding the determinants of healthy mental ageing is a priority for society today1,2. So far, we know that intelligence differences show high stability from childhood to old age3,4 and there are estimates of the genetic contribution to intelligence at different ages5,6. However, attempts to discover whether genetic causes con- tribute to differences in cognitive ageing have been relatively uninformative7–10. Here we provide an estimate of the genetic and environmental contributions to stability and change in intelligence across most of the human lifetime. We used genome-wide single nucleotide polymorphism (SNP) data from 1,940 unrelated individuals whose intelligence was measured in childhood (age 11 years) and again in old age (age 65, 70 or 79 years)11,12. We use a statistical method that allows genetic (co)variance to be estimated from SNP data on unrelated individuals13–17. We estimate that causal genetic variants in linkage disequilibrium with common SNPs account for 0.24 of the variation in cognitive ability change from childhood to old age. Using bivariate analysis, we estimate a genetic correlation between intelligence at age 11 years and in old age of 0.62. These estimates, derived from rarely available data on lifetime cognitive measures, warrant the search for genetic causes of cognitive stability and change.