Malgré la revendication commune selon laquelle le QI national de nombreux pays aurait connu des gains séculaires à travers les décennies, il existe des preuves d’une inversion des gains séculaires de QI, en Angleterre (Flynn, 2009; Shayer & Ginsburg, 2007), au Danemark (Teasdale & Owen, 2005; Teasdale & Owen, 2008), en Norvège (Sundet et al., 2004). Le sujet est néanmoins peu pertinent en ce qui concerne le débat sur les gains séculaires de l’intelligence réelle. L’effet Flynn ne se produit pas sur “g” et la charge en “g” d’un test cognitif diminue avec l’entraînement et l’habitude (te Nijenhuis, 2007). L’effet Flynn n’est pas un Jensen Effect. James Flynn lui-même (2010) a même été forcé d’admettre ceci : “Flynn never said real intelligence levels were rising”.
Score gains on g-loaded tests : No g. Jan te Nijenhuis, Annelies E.M. van Vianen, Henk van der Flier, 2007.
IQ scores provide the best general predictor of success in education, job training, and work. However, there are many ways in which IQ scores can be increased, for instance by means of retesting or participation in learning potential training programs. What is the nature of these score gains? Jensen … argued that the effects of cognitive interventions on abilities can be explained in terms of Carroll’s three-stratum hierarchical factor model. We tested his hypothesis using test–retest data from various Dutch, British, and American IQ test batteries combined into a meta-analysis and learning potential data from South Africa using Raven’s Progressive Matrices. The meta-analysis of 64 test–retest studies using IQ batteries (total N=26,990) yielded a correlation between g loadings and score gains of −1.00, meaning there is no g saturation in score gains. The learning potential study showed that: (1) the correlation between score gains and the g loadedness of item scores is −.39, (2) the g loadedness of item scores decreases after a mediated intervention training, and (3) low-g participants increased their scores more than high-g participants. So, our results support Jensen’s hypothesis. The generalizability of test scores resides predominantly in the g component, while the test-specific ability component and the narrow ability component are virtually non-generalizable. As the score gains are not related to g, the generalizable g component decreases and, as it is not unlikely that the training itself is not g-loaded, it is easy to understand why the score gains did not generalize to scores on other cognitive tests and to g-loaded external criteria.
Foreword, by Charles Goodhart
This book details the fascinating history of the development, production, and use by the private sector of token copper coins during the early years of the Industrial Revolution, 1787-1817. The Industrial Revolution moved workers off the land into factories and thereby greatly increased the demand for small-value transactions money, to pay the wages and to allow the workers some choice in their use of their wage receipts to buy food, drink, and other goods. For a variety of reasons, nicely described by George Selgin, neither the Royal Mint nor commercial banks were willing or able to provide such small-value currency. There was a dearth of small change available to pay wages. The shortage was so severe that it was proving a serious hindrance to the industrial development of Great Britain.
Il est bien connu que la religion exerce des effets positifs sur les comportements prosociaux normatifs. Néanmoins, des recherches menées par Azim Shariff suggèrent que la religion produit ces effets positifs principalement par le biais de la peur du châtiment surnaturel alors que, dans le même temps, la croyance en une bienveillance surnaturelle est associée à un comportement moins prosocial.
Michael D. Grant • William S. Kremen • Kristen C. Jacobson • Carol Franz • Hong Xian • Seth A. Eisen • Rosemary Toomey • Ruth E. Murray • Michael J. Lyons
Behav Genet (2010) 40:438–446
Hereditary influences account for a substantial proportion of the variance in many cognitive abilities. However, there is increasing recognition that the relative importance of genetic and environmental influences may vary across different socioeconomic levels. The overall goal of the present study was to examine whether parental education has a moderating effect on genetic and environmental influences of general cognitive ability in early adulthood (age 19.6 ± 1.5). Participants were 5,955 male twins from the Vietnam Era Twin (VET) Registry. Significant effects of parental education on mean level of general cognitive ability scores were found, but a model without moderating effects of parental education on genetic or environmental influences on cognitive scores proved to be the best fitting model. Some, but not all, previous studies have found significant moderating effects; however, no consistent pattern emerged that could account for between-study differences regarding moderating effects on genetic and environmental influences.