title: Thinking positively: The genetics of high intelligence.
abstract: High intelligence (general cognitive ability) is fundamental to the human capital that drives societies in the information age. Understanding the origins of this intellectual capital is important for government policy, for neuroscience, and for genetics. For genetics, a key question is whether the genetic causes of high intelligence are qualitatively or quantitatively different from the normal distribution of intelligence. We report results from a sibling and twin study of high intelligence and its links with the normal distribution. We identified 360,000 sibling pairs and 9000 twin pairs from 3 million 18-year-old males with cognitive assessments administered as part of conscription to military service in Sweden between 1968 and 2010. We found that high intelligence is familial, heritable, and caused by the same genetic and environmental factors responsible for the normal distribution of intelligence. High intelligence is a good candidate for "positive genetics" - going beyond the negative effects of DNA sequence variation on disease and disorders to consider the positive end of the distribution of genetic effects.
authors.affiliation: King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, London, SE5 8AF, United Kingdom.
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Shakeshaft
authors.affiliation: King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, London, SE5 8AF, United Kingdom.
authors.forename: Maciej
authors.initials: M
authors.lastname: Trzaskowski
authors.affiliation: King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, London, SE5 8AF, United Kingdom.
authors.forename: Andrew
authors.initials: A
authors.lastname: McMillan
authors.affiliation: King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, London, SE5 8AF, United Kingdom.
authors.forename: Eva
authors.initials: E
authors.lastname: Krapohl
authors.affiliation: King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, London, SE5 8AF, United Kingdom.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Simpson
authors.affiliation: King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, London, SE5 8AF, United Kingdom ; Department of Psychiatry, Mount Sinai School of Medicine, NY, 10029, USA.
authors.forename: Avi
authors.initials: A
authors.lastname: Reichenberg
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Box 281, 17177 Stockholm, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Cederlöf
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Box 281, 17177 Stockholm, Sweden.
authors.forename: Henrik
authors.initials: H
authors.lastname: Larsson
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Box 281, 17177 Stockholm, Sweden.
authors.forename: Paul
authors.initials: P
authors.lastname: Lichtenstein
authors.affiliation: King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, London, SE5 8AF, United Kingdom.
authors.forename: Robert
authors.initials: R
authors.lastname: Plomin
keywords: Human genetics; Intelligence; Positive genetics; Siblings; Twins