Grote invloed van intelligentie (en erfelijkheid van intelligentie) op schoolresultaten, gezondheid, sociale klasse e.d.

Het grote ongelijk van Vlaamse onderwijssociologen (Jacobs en Co) : both education and social class are substantially correlated with intelligence en dit is een vrij hoge correlatie. En intelligentie is in hoge mate erfelijk.

 Zie recent rapport van van Plomin en Deary in punt 2 - http://www.nature.com/mp/journal/vaop/ncurrent/full/mp2014105a.html)

Conclusies uit dit rapport

1. Intelligentie is in hoge mate erfelijk en intellignetie beïnvloedt in sterke mate de leerresultaten. Dit betekent ook dat intelligentie correleert met sociale klasse en dus niet afkomstneutraal is zoals Jacobs en Co steeds beweren. Veel Vlaamse sociologen houden hier absoluut geen rekening mee en schrijven de correlatie tussen sociale afkomst en anderzijds deelname aan het aso of hoger onderwijs, PISA-score … op naam van de discriminatie in het onderwijs. Zij streven afkomstloze participatie en leerprestaties na.

 Zo bestempelen Jacobs en Co de hoge relatie tussen het scholingsniveau van de ouders en de PISA-score als een louter sociale of SES-relatie smile-emoticon relatie met sociaal-economische status). Dit is ook het geval in de PISA-rapporten. In Onderwijskrant betwisten we al vee jaren de term SES. Bij de invloed van het scholingsniveau van de ouders gaat het in sterkere mate om de invloed van de aanleg (intelligentie) dan om de invloed van sociale factoren. En leerlingen met een hogere intelligentie halen ook meer profijt uit de invloed van de sociale omgeving. De school is niet almachtig en is dus geenszins in staat om de invloed van de aanleg en van de omgeving uit te vlakken.

2. Citaat uit Expert Review Molecular Psychiatry advance online publication van R Plomin and I J Deary -16 September 2014: Genetics and intelligence differences: five special findings (zie rapport op Internet)

Education and social class (which is indexed by occupation, or income, or by the relative deprivation-affluence of where a person lives) are often assumed to be indicators of a person’s environmental influences, but they are correlated with intelligence, which has a high heritability.

… Education, social class and intelligence—correlate because of shared genetic and/or environmental causes. (In andere studies lezen we ook: dat hoger de intelligentie van leerlingen is, hoe meer profijt ze kunnen halen uit de invloed van de omgeving (gezin, onderwijs …) Education and social class (which is indexed by occupation, or income, or by the relative deprivation-affluence of where a person lives) are often assumed to be indicators of a person’s environmental influences, but they are correlated with intelligence, which has a high heritability.

3.Heritability increases dramatically from infancy through adulthood despite genetic stability

For intelligence, heritability increases linearly, from (approximately) 20% in infancy to 40% in adolescence, and to 60% in adulthood. Some evidence suggests that heritability might increase to as much as 80% in later adulthood47 but then decline to about 60% after age 80.48. Thus, the question becomes, why does the heritability of intelligence increase during development despite strong genetic stability from age to age? That is, the same genes largely affect intelligence across the life course and yet genes account for more variance as time goes by

4.Intelligence indexes general genetic effects across diverse cognitive and learning abilities

Another special genetic feature of intelligence is that its differences are caused by genes that affect cognitive abilities as diverse as, for example, spatial ability, vocabulary, processing speed, executive function and memory. Most of the genetic action lies with these general (highly pleiotropic) effects, captured by intelligence, rather than effects specific to each ability, leading to a Generalist Genes

…Education and social class are often assumed to be indicators of environmental influences, but they are correlated with intelligence, which has a high heritability. … there are genetic causes of some of the educational and social class differences in the populations studied, and these overlap with the genetic causes of intelligence differences

5. IQ-Finding that, in twin and GCTA studies, the same genes influence intelligence and social epidemiologists’ ‘environmental’ variables of education, social class, and height can enlighten research in health and social inequalities. It leads to the hypothesis that GPS scores for intelligence might contribute to health outcomes and mortality, and that these might account for some of the associations between education and class and mortality.

6. Abstract

Intelligence is a core construct in differential psychology and behavioural genetics, and should be so in cognitive neuroscience. It is one of the best predictors of important life outcomes such as education, occupation, mental and physical health and illness, and mortality. Intelligence is one of the most heritable behavioural traits. Here, we highlight five genetic findings that are special to intelligence differences and that have important implications for its genetic architecture and for gene-hunting expeditions. (i) The heritability of intelligence increases from about 20% in infancy to perhaps 80% in later adulthood. (ii) Intelligence captures genetic effects on diverse cognitive and learning abilities, which correlate phenotypically about 0.30 on average but correlate genetically about 0.60 or higher. (iii) Assortative mating is greater for intelligence (spouse correlations ~0.40) than for other behavioural traits such as personality and psychopathology (~0.10) or physical traits such as height and weight (~0.20). Assortative mating pumps additive genetic variance into the population every generation, contributing to the high narrow heritability (additive genetic variance) of intelligence. (iv) Unlike psychiatric disorders, intelligence is normally distributed with a positive end of exceptional performance that is a model for ‘positive genetics’. (v) Intelligence is associated with education and social class and broadens the causal perspectives on how these three inter-correlated variables contribute to social mobility, and health, illness and mortality differences. These five findings arose primarily from twin studies. They are being confirmed by the first new quantitative genetic technique in a century—Genome-wide Complex Trait Analysis (GCTA)—which estimates genetic influence using genome-wide genotypes in large samples of unrelated individuals. Comparing GCTA results to the results of twin studies reveals important insights into the genetic architecture of intelligence that are relevant to attempts to narrow the ‘missing heritability’ gap.