A Place at the Policy Table? Behavior Genetics and Estimates of Family Environmental Effects on IQ

A Place at the Policy Table? Behavior Genetics and Estimates of Family Environmental Effects on IQ

David C. Rowe (1997)

The knowledge generated in behavior genetic studies is not often made a part of social policy deliberations. The argument of this article is that behavior genetics belongs at the social policy table. Perhaps ironically, behavior genetics is one of the best methods for understanding environmental influences. Behavior genetic studies can reveal which traits are most influenced by shared environment and, thus, which are most malleable through changes in shared environments. The current consensus of behavior genetic studies is that IQ is not a particularly malleable trait, especially after childhood. Furthermore, for working-to middle-class families, the shared environmental effects on IQ in childhood seem to be temporary rather than lasting. Behavior genetics also can estimate genetic and family environmental components of racial differences in IQ because quantitative genetic models now permit the simultaneous analysis of group means and individual variation. Although not as directly relevant to policy as targeted research on specific policy options, behavior genetics clearly deserves representation.

Do People Make Environments or Do Environments Make People?

Do People Make Environments or Do Environments Make People?

DAVID C. ROWE 2001

ABSTRACT: This article discusses the influence of people’s genetic make-up on their mental states of happiness and depression. Contrary to the conventional wisdom, great fortune does not guarantee happiness; neither does great misfortune assure depression. Emotional states are surprisingly immune to “objective” social circumstances. A biological basis for this relative immunity is that people possess biological set points for these emotional states, rendering the effects of most life events transitory. Genotypes also have indirect effects. People react differently to psychological stressors depending on their genotypes. A susceptible person may succumb to depression, whereas a resilient person may remain unaffected. People also expose themselves to different social environments. Exposure to controllable life events is partly a result of genetic predispositions. Consilience requires that this biological individuality be considered in any understanding of human behavior, including the pursuit of happiness.

Genetic influences on ‘environmental’ factors

Genetic influences on ‘environmental’ factors

A. A. E. Vinkhuyzen, S. van der Sluis, E. J. C. de Geus, D. I. Boomsma and D. Posthuma (2009)

Childhood environment, social environment and behavior, leisure time activities and life events have been hypothesized to contribute to individual differences in cognitive abilities and physical and emotional well-being. These factors are often labeled ‘environmental’, suggesting they shape but not reflect individual differences in behavior. The aim of this study is to test the hypothesis that these factors are not randomly distributed across the population but reflect heritable individual differences. Self-report data on Childhood Environment, Social Environment and Behavior, Leisure Time Activities and Life Events were obtained from 560 adult twins and siblings (mean age 47.11 years). Results clearly show considerable genetic influences on these factors with mean broad heritability of 0.49 (0.00–0.87). This suggests that what we think of as measures of ‘environment’ are better described as external factors that might be partly under genetic control. Understanding causes of individual differences in external factors may aid in clarifying the intricate nature between genetic and environmental influences on complex traits.

The nature of nurture: Genetic influence on ‘environmental’ measures

The nature of nurture: Genetic influence on “environmental” measures

Robert Plomin and C. S. Bergeman.

Behavioral and Brain Sciences (1991) 14, 373-427.

Abstracts. Evidence for genetic influence on environmental measures will emerge in quantitative genetic analyses if genetically influenced characteristics of individuals are assessed by these environmental measures. Recent twin and adoption studies indicate substantial genetic influence when measures of the environment are treated as phenotypes in genetic analyses. Genetic influence has been documented for measures as diverse as videotaped observations of parental behavior toward their children, ratings by parents and children of their family environment, and ratings of peer groups, social support, and life events. Evidence for genetic influence on environmental measures includes some of the most widely used measures of environment – the Home Observation for Measurement of the Environment, the Family Environment Scales, and the Social Readjustment Rating Scale of life events, for example. The goal of this article is to document and discuss these findings and to elicit commentary that might help to shape the course of research on this topic, which has far-reaching implications for the behavioral and brain sciences.

Race-IQ debate : sur la probabilité de la théorie génétique

(J’ai désactivé les commentaires dans la mesure où l’article présent est très loin d’être achevé, et probablement causera des lags de chargements si la page devient trop allongé. Mais comme la cadence du blog ralentit, je le poste quand même. Certaines parties sont en anglais, dû à un manque de temps pour les traductions, qui sera fait dans un avenir proche. D’autres parties sont peut-être aussi redondantes voire inutiles, et seront probablement effacées dans la version finale de l’article. Tant que ce message en gras ne disparaît pas, l’article n’est pas achevé, les liens et images manquants, et je ne crois pas sage, donc, que ce brouillon non structuré mérite d’être cité. En attendant, il y a de quoi lire.)

1. Persistence of The Black-White IQ Gap
2. Africans : Poverty, Geography, and Infectious Disease
3. Interpretation of the Regression to the Mean
4. Within-Group Heritability (WGH) vs Between-Group Heritability (BGH)
5. Transracial Adoption and the IQ of Mixed-Race
6. Africans : Parenting, Culture, and Discrimination
7. Socio-Economic Status : A Moderate of Genetic Influences on IQ
8. Improving IQ Through Interventions : A Broken Dream
9. The Flynn Effect : A Mere Artifact
10. No Bias : Reliability and Validity of IQ Tests
11. National IQs : Explaining Differences in Achievement
12. Evolutionary Theory and the Case for Race Realism

Pourquoi l’école et la culture sont importantes : Une critique de Nisbett

Dans son ouvrage “Intelligence and How to get it”, (2009), Nisbett se fait l’avocat de la théorie environnementale et culturelle qui stipule que l’environnement est plus important que les gènes pour déterminer le succès économique et social, ainsi que le QI.

Bien que Nisbett semble plus ou moins admettre l’idée que le QI mesure des capacités réelles, et qu’il soit hautement héritable, il ne croit pas à l’idée que les différences de QI entre les races puissent avoir ne serait-ce même qu’une petite composante génétique. Son modèle est celui d’un 0% génétique, et 100% environnement en ce qui concerne les différences raciales. Mais la théorie culturelle que Nisbett défend offre peu d’arguments face au corps de preuves supportant la théorie génétique.

La discrimination par la couleur de peau : Test du colorisme

Le colorisme est une théorie proposée pour expliquer pourquoi les individus à peaux foncées sont socio-économiquement moins favorisés que les individus à peaux claires. Ce type de discrimination serait universelle, opérant à l’intérieur d’un groupe racial et entre groupes raciaux, et ne s’appliquerait donc pas seulement aux africains. On dit aussi que les parents appliqueraient même cette “discrimination” à l’encontre de leurs enfants, en favorisant les enfants ayant une peau plus claire. L’idée générale serait que cette discrimination, dont l’effet est tout à fait indépendant de tout autre caractéristique, prend place dans tous les milieux, que ce soit à l’école ou sur le marché du travail. S’il existe un seul endroit où cette discrimination n’est pas opérante, ou si un des sexes (masculin ou féminin) n’est pas affectée par ce type de discrimination, la thèse s’en retrouve complètement fragilisée.

Régression vers la moyenne et prédiction génétique

Les différences de QI entre les blancs et les noirs se traduisent statistiquement par des régressions vers la moyenne. Plus exactement, vers différentes moyennes. Des critiques ont été portées quant à ce phénomène et l’interprétation héréditariste de celui-ci. La présente étude tendra à démontrer (1) que ce phénomène n’est pas un artefact statistique et (2) les régressions supporte la thèse génétique et non la thèse culturelle.