Cognitive ability of preschool, primary and secondary school children in Costa Rica.

Cognitive abilities of children in Costa Rica and Austria were compared using three age groups (N = 385/366). Cognitive ability tests (mental speed, culture reduced/fluid intelligence, literacy/crystallized intelligence) were applied that differed in the extent to which they refer to school-related knowledge. Preschool children (kindergarten, 5-6 years old, N(CR) = 80, N(Au) = 51) were assessed with the Coloured Progressive Matrices (CPM), primary school children (4th grade, 9-11 years old, N(CR) = 71, N(Au) = 71) with ZVT (a trail-making test), Standard Progressive Matrices (SPM) and items from PIRLS-Reading and TIMSS-Mathematics, and secondary school students (15-16 years old, N(CR) = 48, N(Au) = 48) with ZVT, Advanced Progressive Matrices (APM) and items from PISA-Reading and PISA-Mathematics. Additionally, parents and pupils were given questionnaires covering family characteristics and instruction. Average cognitive abilities were higher in Austria (Greenwich-IQ M(CR) = 87 and M(Au) = 99, d(IQ) = 12 points) and differences were smaller in preschool than in secondary school (d(IQ) = 7 vs 20 points). Differences in crystallized intelligence were larger than in fluid intelligence (mental speed: d(IQ) = 12, Raven: d(IQ) = 10, student achievement tests: d(IQ) = 17 IQ points). Differences were larger in comparisons at the level of g-factors. Austrian children were also taller (6.80 cm, d = 1.07 SD), but had lower body mass index (BMI(CR) = 19.35 vs BMI(Au) = 17.59, d = -0.89 SD). Different causal hypotheses explaining these differences are compared.

International differences in the speed of cognitive development: A systematic examination of the existence of the Simber Effect.

The Simber Effect refers to the phenomenon whereby, in Arabic countries, young children have an IQ that is little different from that of Western children but that these differences increase throughout childhood culminating in a difference of around 20 points by adulthood. The true nature of this phenomenon is revealed by an examination of 125 samples from all around the globe measured with Raven's Progressive Matrices. We show that in many cases different speeds of cognitive development increase the IQ score differences between countries mostly between 4 and 9 years of age, and that these increases can in part be explained by poor environmental conditions. However, the patterns are not completely clear, either in terms of regularity or strengths. Methodological problems, in particular the cross-sectional designs of the included samples, as well as the significance of the Simber Effect for country comparisons in intelligence are discussed.

Wealth, intelligence, politics and global fertility differentials.

Demographic trends in today's world are dominated by large fertility differentials between nations, with 'less developed' nations having higher fertility than the more advanced nations. The present study investigates whether these fertility differences are related primarily to indicators of economic development, the intellectual level of the population, or political modernity in the form of liberal democracy. Results obtained with multiple regression, path models and latent variable models are compared. Both log-transformed GDP and measures of intelligence independently reduce fertility across all methods, whereas the effects of liberal democracy are weak and inconsistent. At present rates of fertility and mortality and in the absence of changes within countries, the average IQ of the young world population would decline by 1.34 points per decade and the average per capita income would decline by 0.79% per year.

Designer babies on tap? Medical students' attitudes to pre-implantation genetic screening.

This paper describes two studies about the determinants of attitudes to pre-implantation genetic screening in a multicultural sample of medical students from the United States. Sample sizes were 292 in study 1 and 1464 in study 2. Attitudes were of an undifferentiated nature, but respondents did make a major distinction between use for disease prevention and use for enhancement. No strong distinctions were made between embryo selection and germ line gene manipulations, and between somatic gene therapy and germ line gene manipulations. Religiosity was negatively associated with acceptance of "designer baby" technology for Christians and Muslims but not Hindus. However, the strongest and most consistent influence was an apparently moralistic stance against active and aggressive interference with natural processes in general. Trust in individuals and institutions was unrelated to acceptance of the technology, indicating that fear of abuse by irresponsible individuals and corporations is not an important determinant of opposition.

By their words ye shall know them: Evidence of genetic selection against general intelligence and concurrent environmental enrichment in vocabulary usage since the mid 19th century.

It has been theorized that declines in general intelligence (g) due to genetic selection stemming from the inverse association between completed fertility and IQ and the Flynn effect co-occur, with the effects of the latter being concentrated on less heritable non-g sources of intelligence variance. Evidence for this comes from the observation that 19th century populations were more intellectually productive, and also exhibited faster simple reaction times than modern ones, suggesting greater information-processing ability and therefore higher g. This co-occurrence model is tested via examination of historical changes in the utilization frequencies of words from the highly g-loaded WORDSUM test across 5.9 million texts spanning the period 1850-2005. Consistent with predictions, words with higher difficulties (δ parameters from Item Response Theory) and stronger negative correlations between pass rates and completed fertility declined in use over time whereas less difficult and less strongly selected words, increased in use over time, consistent with a Flynn effect stemming in part from the vocabulary enriching effects of increases in population literacy. These findings persisted when explicitly controlled for word age, changing literacy rates and temporal autocorrelation. These trends constitute compelling evidence for the co-occurrence model.

Ability differentials between nations are unlikely to disappear.

Comments on the original article, "Intelligence: New findings and theoretical developments," by R. E. Nisbett, J. Aronson, C. Blair, W. Dickens, J. Flynn, D. F. Halpern, and E. Turkheimer (see record 2011-30298-001). This comment challenges Nisbett et al's argument that Flynn effect gains will eliminate cross-national IQ inequalities "by the end of the 21st century and falsify the hypothesis that some nations lack the intelligence to fully industrialize" (p. 140). The present authors find that this optimism is not justified by the evidence. In Europe and the United States, Flynn effects are indeed rare in cohorts born after about 1980. Furthermore, it is necessary to distinguish between accelerated childhood development and higher adult intelligence.

National IQs predict differences in scholastic achievement in 67 countries.

This paper examines the relationship of the national IQs reported by Lynn & Vanhanen (2002, 2006) to national achievement in mathematics and science among 8th graders in 67 countries. The correlation between the two is 0.92 and is interpreted as establishing the validity of the national IQs. The correlation is so high that national IQs and educational achievement appear to be measures of the same construct. National differences in educational achievement are greater than differences in IQ, suggesting an amplifier effect such that national differences in IQs amplify differences in educational achievement. Controlling for national differences in IQ, slight inverse relationships of educational achievement are observed with political freedom, subjective well-being, income inequality, and GDP. However, public expenditure on education (as % of GDP) was not a significant predictor of differences in educational achievement.