The Wilson Effect: The Increase in Heritability of IQ With Age

Bouchard, Thomas J.

doi:10.1017/thg.2013.54

Cited by 125 publications

(75 citation statements)

References 63 publications

(97 reference statements)

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“…Among the genes included in the top pathways identified in this study, there was the BDNF, a regulator of NRN1 expression. According to all these data and given the described gradual increase in heritability of IQ from childhood to late adolescence (Deary et al 2009;Bouchard 2013) and the reported early occurrence of intellectual impairment even years before the onset of the psychotic symptoms (Cannon et al 2002), it is plausible that those genes that influence brain development, as NRN1, may be modulating illness traits, as IQ and age at onset, and ultimately influencing the risk for these disorders.…”

Section: Discussionmentioning

confidence: 99%

Involvement of NRN1 gene in schizophrenia-spectrum and bipolar disorders and its impact on age at onset and cognitive functioning

Fatjó‐Vilas

Prats

Pomarol‐Clotet

et al. 2015

The World Journal of Biological Psychiatry

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Objectives: Neuritin 1 gene (NRN1) is involved in neurodevelopment processes and synaptic plasticity and its expression is regulated by brain-derived neurotrophic factor (BDNF). We aimed to investigate the association of NRN1 with schizophrenia-spectrum disorders (SSD) and bipolar disorders (BPD), to explore its role in age at onset and cognitive functioning, and to test the epistasis between NRN1 and BDNF. Methods: The study was developed in a sample of 954 SSD/BPD patients and 668 healthy subjects. Genotyping analyses included 11 SNPs in NRN1 and one functional SNP in BDNF. Results: The frequency of the haplotype C-C (rs645649-rs582262) was significantly increased in patients compared to controls (P ¼ 0.0043), while the haplotype T-C-C-T-C-A (rs3763180-rs10484320-rs4960155-rs9379002-rs9405890-rs1475157) was more frequent in controls (P ¼ 3.1 Â 10 À5). The variability at NRN1 was nominally related to changes in age at onset and to differences in intelligence quotient, in SSD patients. Epistasis between NRN1 and BDNF was significantly associated with the risk for SSD/BPD (P ¼ 0.005). Conclusions: Results suggest that: (i) NRN1 variability is a shared risk factor for both SSD and BPD, (ii) NRN1 may have a selective impact on age at onset and intelligence in SSD, and (iii) the role of NRN1 seems to be not independent of BDNF. ARTICLE HISTORY

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Section: Discussionmentioning

confidence: 99%

Involvement of NRN1 gene in schizophrenia-spectrum and bipolar disorders and its impact on age at onset and cognitive functioning

Fatjó‐Vilas

Prats

Pomarol‐Clotet

et al. 2015

The World Journal of Biological Psychiatry

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“…For instance, the Wilson Effect describes the increase in the heritability of IQ with age; monozygotic twins become more, rather than less similar, as they age (Wilson, 1983). This reflects changes in gene expression over the developmental lifespan and the influence that the expression of genotype has on shaping environment (Bouchard, 2013). …”

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confidence: 99%

Individual differences are more than a gene × environment interaction: The role of learning.

Byrom

Murphy

2018

Journal of Experimental Psychology: Animal Learning and Cogniti

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Individual differences in behavior are understood generally as arising from an interaction between genes and environment, omitting a crucial component. The literature on animal and human learning suggests the need to posit principles of learning to explain our differences. One of the challenges for the advancement of the field has been to establish how general principles of learning can explain the almost infinite variation in behavior. We present a case that: 1) individual differences in behavior emerge, in part, from principles of learning; 2) associations provide a descriptive mechanism for understanding the contribution of experience to behavior; 3) learning theories explain dissociable aspects of behavior. We use four examples from the field of learning to illustrate the importance of involving psychology, and associative theory in particular, in the analysis of individual differences, these are; i) fear learning, ii) behavior directed to cues for outcomes (i.e., sign-and goaltracking), iii) stimulus learning related to attention, and iv) human causal learning. Individual Differences 3A goal of research into learning is to characterize how behavior changes with experience within and across species. Thorndike's (1898) Law of Effect was an early attempt to characterize the effect of experience on behavior. In offering a general law of how experience contributes to behavior, Thorndike was also giving an account of how an individual becomes unique.The classic example of Thorndike's method involved cats and an apparatus known as a puzzle box (Thorndike, 1898). The box was a rudimentary cage with latches and gates to afford escape. The cats' dislike of confined space provided a natural motivation to engage in behaviors that might serendipitously lead to release. Thorndike observed that the cats made many false starts but eventually made a response that enabled escape. With repeated exposure to the box, latency to escape decreased. The Law of Effect stated that behaviors preceding any form of 'satisfaction' (e.g., escape) would be reinforced and made more likely on subsequent trials. However, rather than considering this principle as limiting an animal's flexibility to learn, the law only restricts the conditions for learning. Consider that outside the lab, different humans can successfully complete a motivated goal in different ways. They may behave differently but the same Law of Effect strengthens their behaviors.The goals of this paper are to present the case for the individual differences approach to learning theory. We will argue that (1) learning mediates the influence of genes and environment on behavior and (2) there is complexity, to be explored, within models of learning that can account for diversity in learning. Specifically, we suggest that while genes and environment may contribute to the development of differences in learning, that an individual's phenotype interacts with experience and the memories of experience to further cause individual differences. As such, the study of individual diff...

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“…• Siblings reared together in the same home have IQ's that are more similar than those of adopted children raised together in the same environment [8].…”

Section: Evidence Of Genetic Influences In Iqmentioning

confidence: 99%

“…While a number of individual genes have been reported to be associated with IQ, none have a strong effect [57]. There is growing interest in the potential for epigenetics (a stably heritable phenotype resulting from changes in a chromosome without alterations in the DNA sequence) to influence cognition [8]. Such epigenetic 'heritability' may occur through either mitosis or meiosis and therefore has the potential to explain at least part of the high heritability of intelligence.…”

Section: Please Notementioning

confidence: 99%

Factors Influencing Intelligence Quotient

Oommen¹

2014

JNSK

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AbbreviationsIQ: Intelligence Quotient; WAIS: Wechsler Adult Intelligence Scale IntroductionThe abbreviation "IQ" comes from the German term Intelligent-Quotient, originally coined by psychologist William Stern. Intelligence quotient, or IQ, is a score derived from one of several different standardized tests designed to assess relative intelligence. Some of the popular standardized tests include the Stanford-Binet Intelligence Scale and the Wechsler Adult Intelligence Scale (WAIS).The Stanford-Binet Intelligence Scale is now in its Fifth Edition. It is a cognitive ability and intelligence test that is used to diagnose developmental or cognitive deficiencies in young children. The test measures five weighted factors and consists of both verbal and nonverbal subtests. The five factors being tested are knowledge, quantitative reasoning, visual-spatial processing, working memory, and fluid reasoning [1].Wechsler Adult Intelligence Scale (WAIS) is a test designed to measure intelligence in adults and older adolescents. Based on standard scoring of the subject's rank order on the test item content with the median score set to 100, and a standard deviation of 15, although not all tests adhere to that assignment of 15 IQ points to each standard deviation. It is currently in its fourth edition (WAIS-IV) released in 2008 [2].IQ tests generally are reliable enough that most people ages ten and older have similar IQ scores throughout life [3]. But some individuals score very differently when taking the same test at different times or when taking more than one kind of IQ test at the same age. It has been noted that 25% of assessed individuals will obtain a 10-point IQ score difference with another IQ battery. Even though not all studies indicate significant discrepancies between intelligence batteries at the group level the absence of differences at the individual level cannot be automatically assumed [4]. Variations in IQ scores are based on an individual's specific knowledge, vocabulary, expressive language and memory skills, visual special abilities, fine motor coordination and perceptual skills. Moreover ones emotional anxiety, tension and unfamiliarity with the testing process can also influence the IQ score [5] Many children in the famous longitudinal Genetic Studies of Genius begun in 1921 by Lewis Terman showed declines in IQ as they grew up. Terman recruited school pupils based on referrals from teachers, and gave them his StanfordBinet IQ test. Children with an IQ above 140 by that test were included in the study. There were 643 children in the main study group. When the students who could be contacted again (503 students) were retested at high school age, they were found to have dropped 9 IQ points on average in Stanford-Binet IQ. More than two dozen children dropped by 15 IQ points and six by 25 points or more. But parents of those children thought that the children were still as bright as ever, or even brighter [6].The particular genetic and environmental factors that determine IQ have been difficult to pin down...

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The Wilson Effect: The Increase in Heritability of IQ With Age

Cited by 125 publications

References 63 publications

Involvement of NRN1 gene in schizophrenia-spectrum and bipolar disorders and its impact on age at onset and cognitive functioning

Involvement of NRN1 gene in schizophrenia-spectrum and bipolar disorders and its impact on age at onset and cognitive functioning

Individual differences are more than a gene × environment interaction: The role of learning.

Factors Influencing Intelligence Quotient

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