Cited by 702Cognitive Abilities and TestingGenetic Associations and EpidemiologyIntergenerational and Educational Inequality Studies

Genetics and intelligence differences: five special findings

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Plomin, R, Deary, I J·2015·Molecular Psychiatry

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.

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  1. Carroll JB. Human cognitive abilities. Cambridge University Press: New York, 1993.

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Authors
Plomin, R., & Deary, I. J.
Affiliations
  • King's College London (GB)
  • University of Edinburgh (GB)
Corresponding author
Plomin, R
Venue
Molecular Psychiatry
Published
2014-09-16
Volume
20
Issue
1
Pages
98-108
ISSN
  • 1359-4184 (ISSN-L)
  • 1476-5578
OpenAlex
W1978517482
Cited by
702
References
128
Citations by year
2026: 38 · 2025: 40 · 2024: 56 · 2023: 53 · 2022: 61 · 2021: 66 · 2020: 71 · 2019: 94 · 2018: 70 · 2017: 62 · 2016: 53 · 2015: 34 · 2014: 3
FWCI
6.81
Type
journal article
Language
en
Open access
Locations
  • Molecular Psychiatry (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • Research Portal (King's College London) (publishedVersion, other-oa)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Edinburgh Research Explorer (University of Edinburgh) (submittedVersion, cc-by)
Funders
  • University of Edinburgh (MR/K026992/1)
  • Centre for Cognitive Ageing and Cognitive Epidemiology (MR/K026992/1)
  • Directorate for Biological Sciences
  • Medical Research Council (MR/K026992/1, G0901245, G19/2, 295366)
  • Biotechnology and Biological Sciences Research Council (MR/K026992/1, BB/F019394/1)
Topics
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Cognitive Abilities and Testing
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Genetic Associations and Epidemiology
  • Social Sciences › Sociology and Political Science › Intergenerational and Educational Inequality Studies
Keywords
intelligence, heritability, genetic architecture, assortative mating, exceptional performance, social class, social mobility, missing heritability, GCTA, twin studies, cognitive ability, gene discovery
MeSH terms
Genetics, Behavioral, Genotype, Humans, Intelligence, Phenotype, Genetic Variation, Meta-Analysis as Topic, Genetic Predisposition to Disease, Genome-Wide Association Study

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