Childhood socioeconomic status amplifies genetic effects on adult intelligence

Regional brain structure mediates the association between sleep quality and intellectual abilities: the moderating role of socioeconomic status

This study aims to reveal the association between sleep quality and crystallized intelligence (Gc), fluid intelligence (Gf), and the underlying brain structural basis. Using the data from the Human Connectome Project (N = 1087), we performed mediation analysis to explore whether regional brain structure related to sleep quality mediate the association between sleep quality and intellectual abilities, and further examined whether socioeconomic status (i.e., income and education level) moderate the mediation effect. Results showed that poorer sleep quality was associated with lower Gc rather than Gf, and worse sleep quality was associated with smaller volume and surface area in temporal lobe, including inferior temporal gyrus and middle temporal gyrus. Notably, temporal lobe structures mediated the association between sleep quality and Gc rather than Gf. Furthermore, socioeconomic status (i.e., income and education level) moderated the mediating effect, showing low socioeconomic status has a more significant mediating effect with stronger association between sleep quality and Gc as well as stronger association between temporal lobe structure and Gc in low socioeconomic status group. These findings suggest that individuals with higher socioeconomic status are less susceptible to the effect of sleep quality on Gc.

Impaired executive functioning in children of women with epilepsy

OBJECTIVE

While neurodevelopmental symptoms are often seen in children of mothers with epilepsy, research specifically addressing executive function (EF) in this population is limited. This study aims to investigate EF in children of mothers with epilepsy, both with and without fetal exposure to anti-seizure medications, compared to typically developing children whose mothers do not have epilepsy.

METHODS

We evaluated EF in children aged 8 to 17 years born to mothers with clinically validated diagnoses of epilepsy, using the Behavior Rating Inventory of Executive Function completed by the mothers. The results were then compared to a typically developing control group at the same age living in the same geographic area.

RESULTS

The results showed significantly higher levels of EF problems in children of mothers with epilepsy who were exposed (p = 0.005, d = 0.63), and unexposed (p = 0.001, d = 0.74) to anti-seizure medications during pregnancy, compared to typically developing children. There was no significant difference in EF problems between the exposed and unexposed groups. These findings remained statistically significant after adjusting for mothers' education levels, and when excluding participants exposed to valproate during pregnancy.

SIGNIFICANCE

This study highlights the increased risk of EF problems in children of mothers with epilepsy, independent of exposure to anti-seizure medications. Findings underscore the importance of continuous monitoring of EF in these children and highlights the need for further research into the diverse factors affecting EF development in this group.

Comorbidities and Disease Duration in Tourette Syndrome: Impact on Cognition and Quality of Life of Children

BACKGROUND

Cognitive functions represent foundational factors for mental health and quality of life (QoL). In Tourette syndrome (TS), psychiatric comorbidities are common and have been inconsistently reported to affect the cognition and QoL of patients, while the role of tic disorder duration has not been yet explored.

METHODS

To examine how comorbidities and TS duration may influence cognition and QoL, N = 80 children with TS (6-16 years) were evaluated using the Wechsler Intelligence Scale for Children (WISC-IV). Standardized questionnaires were used to assess the presence and severity of TS main comorbidities and QoL. Data were interpreted using linear correlations, regression, and mediation analysis.

RESULTS

Depression and attention-deficit/hyperactivity disorder (ADHD) symptoms accounted for poorer cognitive performance. Anxiety oppositely predicted better cognitive performance, while no significant role for obsessive compulsive disorder (OCD) was observed. Disease duration was associated with lower total IQ, verbal reasoning, and working memory abilities. Depression, anxiety, and TS duration also deeply influenced QoL measures.

CONCLUSIONS

TS common comorbidities have a differential impact on the cognitive abilities of children and adolescents, which translates into a complex influence on their perceived QoL. A longer clinical history of tics was related to worse cognitive outcomes, which prompts further consideration of disease duration in both clinical and research settings involving children and adolescents.

A Longitudinal Analysis of Gene x Environment Interaction on Verbal Intelligence Across Adolescence and Early Adulthood

The Scarr-Rowe hypothesis proposes that the heritability of intelligence is higher in more advantaged socioeconomic contexts. An early demonstration of this hypothesis was Rowe and colleagues (Rowe et al., Child Dev 70:1151-1162, 1999), where an interaction between the heritability of verbal intelligence and parental education was identified in adolescent siblings in Wave I of the National Longitudinal Study of Adolescent to Adult Health. The present study repeated their original analysis at Wave I using contemporary methods, replicated the finding during young adulthood at Wave III, and analyzed the interaction longitudinally utilizing multiple measurements. We examined parental education, family income, and peer academic environment as potential moderators. Results indicated increased heritability and decreased shared environmental variance of verbal intelligence at higher levels of parental education and peer academic environment in adolescence. Moreover, moderation by peer academic environment persisted into adulthood with its effect partially attributable to novel gene-environment interactions that arose in the process of cognitive development.

Evolving the blank slate

We support Uchiyama et al. in the value of genetics, sample diversification, and context measurement. Against the example of vitamins, we highlight the intransigence of many phenotypes. We caution that while culture can mask genetic differences, the dependence of behaviour on genetics is reinvented and unmasked by novel challenges across generations.

Integrating cultural evolution and behavioral genetics

The 29 commentaries amplified our key arguments; offered extensions, implications, and applications of the framework; and pushed back and clarified. To help forge the path forward for cultural evolutionary behavioral genetics, we (1) focus on conceptual disagreements and misconceptions about the concepts of heritability and culture; (2) further discuss points raised about the intertwined relationship between culture and genes; and (3) address extensions to the proposed framework, particularly as it relates to cultural clusters, development, and power. These commentaries, and the deep engagement they represent, reinforce the importance of integrating cultural evolution and behavioral genetics.

Association of maternal body mass index with intellectual disability risk

OBJECTIVES

The study aimed to investigate the association between maternal body mass index (BMI) in early pregnancy and children's intellectual disability (ID) risk in the absence of chromosomal disorders, neurofibromatosis and tuberous sclerosis, taking adverse birth outcomes, maternal hypertension/diabetes and maternal socioeconomic status into consideration.

METHODS

We conducted a cohort study of singletons without common genetic defects born in Sweden during 1992-2006, and followed them from birth until 31 December 2014 (n=1 186 836). Cox proportional hazards models were used to analyse the association between maternal BMI in early pregnancy and the risk of offspring's ID.

RESULTS

The risk of ID was higher in children born to mothers who were underweight (HR=1.21, 95% CI=1.07 to 1.36), overweight (HR=1.28, 95% CI=1.21 to 1.34) or had obesity class I (HR=1.63, 95% CI=1.53 to 1.74), obesity class II (HR=2.08, 95% CI=1.88 to 2.30) and obesity class III (HR=2.31, 95% CI=1.46 to 3.65) than in children born to normal weight mothers. Results remained consistent after excluding children with adverse birth outcome or born to mothers with gestational hypertension/diabetes. Analysis stratified by maternal education and annual household income showed that the association between maternal underweight and children's ID risk was attenuated among children of mothers with tertiary education or with high income.

CONCLUSIONS

Our findings suggest that maternal underweight or overweight/obesity in early pregnancy was associated with the development of ID in their offspring. This association was independent of the effect of adverse birth outcomes and maternal hypertension/diabetes. High socioeconomic status may attenuate the risk of ID among children of underweight mothers. This study highlights the importance of improving health education before conception to reduce children's ID risk.

Trans-ethnic Meta-analysis of Interactions between Genetics and Early Life Socioeconomic Context on Memory Performance and Decline in Older Americans

Later life cognitive function is influenced by genetics as well as early- and later-life socioeconomic context. However, few studies have examined the interaction between genetics and early childhood factors. Using gene-based tests (iSKAT/iSKAT-O), we examined whether common and/or rare exonic variants in 39 gene regions previously associated with cognitive performance, dementia, and related traits had an interaction with childhood socioeconomic context (parental education and financial strain) on memory performance or decline in European ancestry (EA, N=10,468) and African ancestry (AA, N=2,252) participants from the Health and Retirement Study. Of the 39 genes, 22 in EA and 19 in AA had nominally significant interactions with at least one childhood socioeconomic measure on memory performance and/or decline; however, all but one (father's education by SLC24A4 in AA) were not significant after multiple testing correction (FDR <0.05). In trans-ethnic meta-analysis, two genes interacted with childhood socioeconomic context (FDR <0.05): mother's education by MS4A4A on memory performance, and father's education by SLC24A4 on memory decline. Both interactions remained significant (p<0.05) after adjusting for respondent's own educational attainment, APOE ε4 status, lifestyle factors, BMI, and comorbidities. For both interactions in EA and AA, the genetic effect was stronger in participants with low parental education. Examination of common and rare variants in genes discovered through GWAS shows that childhood context may interact with key gene regions to jointly impact later life memory function and decline. Genetic effects may be more salient for those with lower childhood socioeconomic status.

Cognition in context: Pathways and compound risk in a sample of US non-Hispanic whites

The population of individuals with cognitive impairment and dementia is growing rapidly, necessitating etiological investigation. It is clear that individual differences in cognition later in life have both genetic and multi-level environmental correlates. Despite significant recent progress in cellular and molecular research, the exact mechanisms linking genes, brains, and cognition remain elusive. In relation to cognition, it is unlikely that genetic and environmental risk factors function in a vacuum, but rather interact and cluster together. The purpose of the present study was to examine whether aspects of individual socioeconomic status (SES) explain the cognitive genotype-phenotype association, and whether neighborhood SES modifies the effects of genes and individual SES on cognitive ability. Using data from non-Hispanic White participants in the 2016 wave of the Health and Retirement Study, a national sample of United States adults, we examined links between a polygenic score for general cognition and performance-based cognitive functioning. In a series of weighted linear regressions and formal tests of mediation, we observed a significant genotype-phenotype association that was partially attenuated after including individual education to the baseline model, although little reductions were observed for household wealth or census tract-level percent poverty. These findings suggest that genetic risk for poor cognition is partially explained by education, and this pathway is not modified by poverty-level of the neighborhood.

Modification of Heritability for Educational Attainment and Fluid Intelligence by Socioeconomic Deprivation in the UK Biobank

OBJECTIVE

Socioeconomic factors have been suggested to influence the effect of education- and intelligence-associated genetic variants. However, results from previous studies on the interaction between socioeconomic status and education or intelligence have been inconsistent. The authors sought to assess these interactions in the UK Biobank cohort of 500,000 participants.

METHODS

The authors assessed the effect of socioeconomic deprivation on education- and intelligence-associated genetic variants by estimating the single-nucleotide polymorphism (SNP) heritability for fluid intelligence, educational attainment, and years of education in subsets of UK Biobank participants with different degrees of social deprivation, using linkage disequilibrium score regression. They also generated polygenic scores with LDpred and tested for interactions with social deprivation.

RESULTS

SNP heritability increased with socioeconomic deprivation for fluid intelligence, educational attainment, and years of education. Polygenic scores were also found to interact with socioeconomic deprivation, where the effects of the scores increased with increasing deprivation for all traits.

CONCLUSIONS

These results indicate that genetics have a larger influence on educational and cognitive outcomes in more socioeconomically deprived U.K. citizens, which has serious implications for equality of opportunity.

Cultural Evolution of Genetic Heritability

Behavioral genetics and cultural evolution have both revolutionized our understanding of human behavior-largely independent of each other. Here we reconcile these two fields under a dual inheritance framework, offering a more nuanced understanding of the interaction between genes and culture. Going beyond typical analyses of gene-environment interactions, we describe the cultural dynamics that shape these interactions by shaping the environment and population structure. A cultural evolutionary approach can explain, for example, how factors such as rates of innovation and diffusion, density of cultural sub-groups, and tolerance for behavioral diversity impact heritability estimates, thus yielding predictions for different social contexts. Moreover, when cumulative culture functionally overlaps with genes, genetic effects become masked, unmasked, or even reversed, and the causal effects of an identified gene become confounded with features of the cultural environment. The manner of confounding is specific to a particular society at a particular time, but a WEIRD (Western, educated, industrialized, rich, democratic) sampling problem obscures this boundedness. Cultural evolutionary dynamics are typically missing from models of gene-to-phenotype causality, hindering generalizability of genetic effects across societies and across time. We lay out a reconciled framework and use it to predict the ways in which heritability should differ between societies, between socioeconomic levels and other groupings within some societies but not others, and over the life course. An integrated cultural evolutionary behavioral genetic approach cuts through the nature-nurture debate and helps resolve controversies in topics such as IQ.

Genetic and Environmental Influences on Semantic Verbal Fluency Across Midlife and Later Life

Despite the relevance of semantic fluency measures to risk for dementia and psychiatric disorders, little is known about their genetic and environmental architecture in mid-to-late life. Participants represent 21,684 middle-aged and older adult twins (M = 60.84 years, SD = 11.21; Range 40-89) from six studies from three countries participating in the Interplay of Genes and Environment across Multiple Studies (IGEMS) consortium. All completed the same measure of semantic fluency (naming animals in 60 seconds). Results revealed small-to-moderate phenotypic associations with age and education, with education more strongly and positively associated with fluency performance in females than males. Heritability and environmental influences did not vary by age. Environmental variance was smaller with higher levels of education, but this effect was observed only in males. This is the largest study to examine the genetic and environmental architecture of semantic fluency, and the first to demonstrate that environmental influences vary based on levels of education.

Chimpanzees' (Pan troglodytes) problem-solving skills are influenced by housing facility and captive care duration

Although a large body of primate cognition research is done in captive institutions, little is known about how much individuals from different facilities vary in their experiences and cognitive skills. Here we present the results of an experimental study investigating how physical cognitive skills vary between chimpanzees in relation to captive settings and their time in captivity. We tested 59 chimpanzees housed at two different captive facilities (a rehabilitation center (sanctuary) and a zoo) in three problem-solving tasks. Our results showed that chimpanzees at the two housing facilities significantly differed in overall task performance. On average, the sanctuary chimpanzees outperformed the chimpanzees housed at the zoo in the detour reaching task and the honey trap task. However, the zoo chimpanzees performed slightly better on average in the learning task. We propose that, for this particular sample, the documented differences result from a combination of factors, such as prior experience with cognitive testing, motivation levels and varying degrees of human exposure. Within the sanctuary sample, we found that chimpanzees who arrived at an earlier age at the sanctuary and had therefore spent a larger percentage of their lives in a captive environment, were better problem-solvers than those that arrived at a later age to the sanctuary. Thus, rehabilitation and time in captivity contributed to improved physical cognitive skills in sanctuary chimpanzees. Our results highlight the importance of studying intraspecific variation and the effect that previous experience and living conditions might have on physical cognitive skills in non-human apes. Accordingly, we should be cautious when extrapolating findings of cognitive studies from one population to the species as a whole.

Estimating the Heritability of Experiencing Child Maltreatment in an Extended Family Design

Child-driven genetic factors can contribute to negative parenting and may increase the risk of being maltreated. Experiencing childhood maltreatment may be partly heritable, but results of twin studies are mixed. In the current study, we used a cross-sectional extended family design to estimate genetic and environmental effects on experiencing child maltreatment. The sample consisted of 395 individuals (225 women; M_age = 38.85 years, range_age = 7-88 years) from 63 families with two or three participating generations. Participants were oversampled for experienced maltreatment. Self-reported experienced child maltreatment was measured using a questionnaire assessing physical and emotional abuse, and physical and emotional neglect. All maltreatment phenotypes were partly heritable with percentages for h² ranging from 30% (SE = 13%) for neglect to 62% (SE = 19%) for severe physical abuse. Common environmental effects (c²) explained a statistically significant proportion of variance for all phenotypes except for the experience of severe physical abuse (c² = 9%, SE = 13%, p = .26). The genetic correlation between abuse and neglect was ρ_g = .73 (p = .02). Common environmental variance increased as socioeconomic status (SES) decreased (p = .05), but additive genetic and unique environmental variances were constant across different levels of SES.

Genes, Education, and Labor Market Outcomes: Evidence from the Health and Retirement Study

Recent advances have led to the discovery of specific genetic variants that predict educational attainment. We study how these variants, summarized as a linear index-known as a polygenic score-are associated with human capital accumulation and labor market outcomes in the Health and Retirement Study (HRS). We present two main sets of results. First, we find evidence that the genetic factors measured by this score interact strongly with childhood socioeconomic status in determining educational outcomes. In particular, although the polygenic score predicts higher rates of college graduation on average, this relationship is substantially stronger for individuals who grew up in households with higher socioeconomic status relative to those who grew up in poorer households. Second, the polygenic score predicts labor earnings even after adjusting for completed education, with larger returns in more recent decades. These patterns suggest that the genetic traits that promote education might allow workers to better accommodate ongoing skill biased technological change. Consistent with this interpretation, we find a positive association between the polygenic score and nonroutine analytic tasks that have benefited from the introduction of new technologies. Nonetheless, the college premium remains a dominant determinant of earnings differences at all levels of the polygenic score. Given the role of childhood SES in predicting college attainment, this raises concerns about wasted potential arising from limited household resources.

Early life predictors of intelligence in young adulthood and middle age

BACKGROUND

Studies on early predictors of intelligence often focus on single or few predictors and often on childhood intelligence. This study compared the contributions of a broad selection of potential early predictors of intelligence at different adult ages.

METHODS

Information on predictors was recorded prospectively in the Copenhagen Perinatal Cohort during pregnancy, at delivery, and at 1- and 3-year examinations for children born between 1959-61. Adult intelligence was assessed at three independent follow-ups using three different tests of intelligence: Børge Priens Prøve, Wechsler Adult Intelligence Scale, and Intelligenz-Struktur-Test 2000R. From a total of 4697 cohort members, three non-overlapping samples were derived.

RESULTS

The included predictors explained between 22.2-24.3% of the variance in adult IQ, with parental socioeconomic status and sex explaining 16.2-17.0%. Other consistent predictors were head circumference at birth, increase in head circumference head during the first three years, and 3-year milestones. Head circumference was the most important anthropometric measure compared to measures of weight and length.

CONCLUSION

Besides social status and sex, the strongest and most consistent early predictors of adult intelligence were physical or behavioural characteristics that to some extent reflect brain-and cognitive development.

Midlife Study of the Louisville Twins: Connecting Cognitive Development to Biological and Cognitive Aging

The Louisville Twin Study (LTS) began in 1958 and became a premier longitudinal twin study of cognitive development. The LTS continuously collected data from twins through 2000 after which the study closed indefinitely due to lack of funding. Now that the majority of the sample is age 40 or older (61.36%, N = 1770), the LTS childhood data can be linked to midlife cognitive functioning, among other physical, biological, social, and psychiatric outcomes. We report results from two pilot studies in anticipation of beginning the midlife phase of the LTS. The first pilot study was a participant tracking study, in which we showed that approximately 90% of the Louisville families randomly sampled (N = 203) for the study could be found. The second pilot study consisted of 40 in-person interviews in which twins completed cognitive, memory, biometric, and functional ability measures. The main purpose of the second study was to correlate midlife measures of cognitive functioning to a measure of biological age, which is an alternative index to chronological age that quantifies age as a function of the breakdown of structural and functional physiological systems, and then to relate both of these measures to twins' cognitive developmental trajectories. Midlife IQ was uncorrelated with biological age (- .01) while better scores on episodic memory more strongly correlated with lower biological age (- .19 to - .31). As expected, midlife IQ positively correlated with IQ measures collected throughout childhood and adolescence. Additionally, positive linear rates of change in FSIQ scores in childhood significantly correlated with biological age (- .68), physical functioning (.71), and functional ability (- .55), suggesting that cognitive development predicts lower biological age, better physical functioning, and better functional ability. In sum, the Louisville twins can be relocated to investigate whether and how early and midlife cognitive and physical health factors contribute to cognitive aging.

Gene and environment interplay in cognition: Evidence from twin and molecular studies, future directions and suggestions for effective candidate gene x environment (cGxE) research

Last decade of molecular research in the field of cognitive science has shown that no single approach can give satisfactory results as far as gene hunt is concerned. Cohesive theory of gene-environment interaction seems to be a rational idea for bridging the gap in our knowledge of disorders involving cognitive deficit. It may even be helpful to some extent in resolving issues of missing heritability. We review the current state of play in the area of cognition at genetic and environmental fronts. Evidence of apparent gene-environment (GxE) interactions from various studies has been mentioned with the aim of redirecting the focus of research community towards studying such interactions with the help of sensitive designs and molecular techniques. We re-evaluate candidate gene-environment research in order to emphasize its potential if carried out strategically.

Quality of education impacts late-life cognition

OBJECTIVES

Screening tests of global cognition detect racial differences in scores even after adjustment for educational attainment. Differential educational environments in adolescence may affect individual cognitive function. This study examines the impact of high school educational quality on late-life cognition among community-dwelling older adults.

METHODS/DESIGN

Data were collected from community-dwelling individuals from the Philadelphia Healthy Brain Aging (PHBA) cohort at the University of Pennsylvania Health System. The present analysis included subjects from the PHBA over the age of 55 years without a diagnosis of Parkinson's disease or dementia, who had attended high school in the City of Philadelphia. Cognition was assessed using the Montreal Cognitive Assessment (MoCA); clinical information was abstracted from the subject's electronic health record. High school information was obtained from the Philadelphia Board of Education. After univariable correlations were defined, we performed stepwise multiple linear regression models to determine the most significant predictors of late-life cognitive status.

RESULTS

A total of 130 subjects meeting inclusion criteria were included in the analysis. Years of education, race, educational level, school district, and financial status were all positively associated with MoCA. Significant negative associations included composite vascular risk, attendance at highly segregated schools, and historical poverty status. In stepwise multiple linear regression modeling, the impact of race on cognition remained significant when educational attainment was added to the model but was no longer significant once segregation status was added.

CONCLUSIONS

This work suggests that academic and community factors beyond years of education have a marked impact on late-life cognition.

umx: Twin and Path-Based Structural Equation Modeling in R

Structural equation modeling (SEM) is an important research tool, both for path-based model specification (common in the social sciences) and also for matrix-based models (in heavy use in behavior genetics). We developed umx to give more immediate access, relatively concise syntax and helpful defaults for users in these two broad disciplines. umx supports development, modification and comparison of models, as well as both graphical and tabular outputs. The second major focus of umx, behavior genetic models, is supported via functions implementing standard multigroup twin models. These functions support raw and covariance data, including joint ordinal data, and give solutions for ACE models, including support for covariates, common- and independent-pathway models, and gene × environment interaction models. A tutorial site and question forum are also available.

Adaptive Behavior and Intelligence in Adolescents With Down Syndrome: An Exploratory Investigation

Down syndrome (DS) is characterized by difficulties in both intellectual functioning and adaptive behavior. These sets of abilities are considered as separate but related domains with small to moderate correlations. The main objective of this study was to explore the relationship of intellectual functioning and adaptive behavior in adolescents with DS because previous studies have shown different relationship patterns between these constructs across other syndromes. Fifty-three adolescents with DS were assessed regarding their intellectual functioning whereas adaptive behavior was reported by parents and teachers. Participants showed a better performance on verbal than nonverbal tasks when assessing intellectual functioning, contrary to previous findings. Regarding adaptive behavior, higher social skills were reported than conceptual and practical skills. Intellectual functioning and adaptive behavior showed a medium correlation, consistent with observations in typical population. These results support the exploration of the variability across the DS phenotype.

Physical and Cultural Inheritance Enhance Agency, but What are the Origins of this Concern to Establish a Legacy? A Nationally-Representative Twin Study of Erikson's Concept of Generativity

Generativity-showing concern to establish and guide future generations-has been argued to be a biological adaptation central to cumulative culture and survival, but also, in turn, to be a cultural adaptation dependent on norms. From the perspective of human agency, concern for the future has played a key role in raising agency for generations that follow by creating infrastructure and cultural inheritance. Here, in a population-representative sample of 756 twin-pairs, we present the first test of the genetic and environmental structure of generativity using the Loyola Generativity Scale (short). Genetic analysis of scale sum-scores revealed that shared environmental effects were comparable in magnitude or exceeded effects estimated for genetic differences (A = 0.30 CI95 [- 0.01, 0.61], C = 0.41 [0.25, 0.56], E = 0.86 [0.79, 0.93]). At the item level, a well-fitting genetically-informed model suggested 3 factors influencing generativity via a common-pathway structure. The first was tentatively characterized as reflecting a heritable general concern for the future. The second reflected being a valued source of advice and assistance. The third factor showed only unique environment effects and had as its strongest indicator having had a good influence on the lives of others. Replicability of this structure should be tested in the full version of the scale. Work is needed also to validate influences of generativity on vocations such as teaching and on philanthropic activity improving life for subsequent generations.

Cognitive Functioning in Patients with Pediatric-Onset Multiple Sclerosis, an Updated Review and Future Focus

Pediatric-onset multiple sclerosis (POMS) is relatively rare, but as technology and neuroimaging advance, an increasing number of cases are identified, and our understanding of how multiple sclerosis (MS) impacts the developing brain improves. There are consistent findings in the literature highlighting the impact of MS and other demyelinating diseases on cognitive functioning and cognitive development. We also have a better understanding of how POMS impacts psychosocial functioning and functional outcomes in daily living. This paper hopes to review findings associated with cognitive and psychosocial functioning in patients with POMS, as well as explore more recent advances in the field and how they relate to cognitive and psychosocial outcomes. We also discuss the ongoing need for future studies with a focus on better understanding deficits and disease correlates, but also preventative measures and potential rehabilitation.

Socioeconomic status amplifies genetic effects in middle childhood in a large German twin sample

The Scarr-Rowe hypothesis predicts that the heritability of cognitive abilities is higher in more privileged socioeconomic conditions, meaning that genetic potential can be more fully expressed in environments characterized by high socioeconomic status (SES) compared to low SES. This gene × SES interaction, however, has been replicated mostly in the United States, but not in other Western nations like the United Kingdom. In the current study, we tested the interaction between childhood SES and the heritability of cognitive ability in 3,074 German twin pairs comprising three age cohorts at different developmental stages (mean ages of 11, 17, and 23 years). Higher SES was associated with significantly higher mean cognitive ability scores in the two younger cohorts, with reduced variances at higher SES levels. Results further support the Scarr-Rowe hypothesis in middle childhood, and to some degree in adolescence, but not in adulthood. This indicates that the role of family SES as a moderator of the heritability of cognitive ability changes as children grow older. Moreover, children's shared experiences appear to be explain more variance in cognitive ability at the lower end of the SES distribution in middle childhood and adolescence.

The Color Red Is Implicitly Associated With Social Status in the United Kingdom and China

Research and theorizing on human societies have shown that the color red plays a large role in human psychological functioning. The aim of the present study was to test the association between red and high-status symbols across cultural contexts. Using the Implicit Association Test (IAT) paradigm, across seven experiments (N = 357), we demonstrated that participants exhibited a faster association of red color and logos of high-status stimuli compared to red color and logos of low-status stimuli. The effect was shown among both males and females, with two different types of status symbols (car logos and university logos), and with four different contrast colors (white, gray, green, blue). Moreover, this association was observed in both United Kingdom and China. These findings provide compelling evidence for the implicit association between the color red and high social status across two different cultural contexts.

Intelligence and uncertainty: Implications of hierarchical predictive processing for the neuroscience of cognitive ability

Hierarchical predictive processing (PP) has recently emerged as a candidate theoretical paradigm for neurobehavioral research. To date, PP has found support through its success in offering compelling explanations for a number of perceptual, cognitive, and psychiatric phenomena, as well as from accumulating neurophysiological evidence. However, its implications for understanding intelligence and its neural basis have received relatively little attention. The present review outlines the key tenets and evidence for PP, and assesses its implications for intelligence research. It is argued that PP suggests indeterminacy as a unifying principle from which to investigate the cognitive hierarchy and brain-ability correlations. The resulting framework not only accommodates prominent psychometric models of intelligence, but also incorporates key findings from neuroanatomical and functional activation research, and motivates new predictions via the mechanisms of prediction-error minimization. Because PP also suggests unique neural signatures of experience-dependent activity, it may also help clarify environmental contributions to intellectual development. It is concluded that PP represents a plausible, integrative framework that could enhance progress in the neuroscience of intelligence.

Does the heritability of cognitive abilities vary as a function of parental education? Evidence from a German twin sample

A well-known hypothesis in the behavioral genetic literature predicts that the heritability of cognitive abilities is higher in the presence of higher socioeconomic contexts. However, studies suggest that the effect of socioeconomic status (SES) on the heritability of cognitive ability may not be universal, as it has mostly been demonstrated in the United States, but not in other Western nations. In the present study we tested whether the importance of genetic and environmental effects on cognitive abilities varies as a function of parental education in a German twin sample. Cognitive ability scores (general, verbal, and nonverbal) were obtained on 531 German twin pairs (192 monozygotic, 339 dizygotic, ranging from 7 to 14 years of age; M_age = 10.25, SD = 1.83). Data on parental education were available from mothers and fathers. Results for general cognitive ability and nonverbal ability indicated no significant gene x parental education interaction effect. For verbal ability, a significant nonshared environment (E) x parental education interaction was found in the direction of greater nonshared environmental influences on verbal abilities among children raised by more educated parents.

Intelligence and all-cause mortality in the 6-Day Sample of the Scottish Mental Survey 1947 and their siblings: testing the contribution of family background

Background

Higher early-life intelligence is associated with a reduced risk of mortality in adulthood, though this association is apparently hardly attenuated when accounting for early-life socio-economic status (SES). However, the use of proxy measures of SES means that residual confounding may underestimate this attenuation. In the present study, the potential confounding effect of early-life SES was instead accounted for by examining the intelligence-mortality association within families.

Methods

The association between early-life intelligence and mortality in adulthood was assessed in 727 members of the 6-Day Sample of the Scottish Mental Survey 1947 and, for the first time, 1580 of their younger siblings. These individuals were born between 1936 and 1958, and were followed up into later life, with deaths recorded up to 2015. Cox regression was used to estimate the relative risk of mortality associated with higher IQ scores after adjusting for shared family factors.

Results

A standard-deviation advantage in IQ score was associated with a significantly reduced mortality risk [hazard ratio = 0.76, p < 0.001, 95% confidence interval (CI) (0.68-0.84)]. This reduction in hazard was only slightly attenuated by adjusting for sex and shared family factors [hazard ratio = 0.79, p = 0.002, 95% CI (0.68-0.92)].

Conclusions

Although somewhat conservative, adjusting for all variance shared by a family avoids any potential residual confounding of the intelligence-mortality association arising from the use of proxy measures of early-life SES. The present study demonstrates that the longevity associated with higher early-life intelligence cannot be explained by early-life SES or within-family factors.

Socioeconomic status and genetic influences on cognitive development

Accurate understanding of environmental moderation of genetic influences is vital to advancing the science of cognitive development as well as for designing interventions. One widely reported idea is increasing genetic influence on cognition for children raised in higher socioeconomic status (SES) families, including recent proposals that the pattern is a particularly US phenomenon. We used matched birth and school records from Florida siblings and twins born in 1994-2002 to provide the largest, most population-diverse consideration of this hypothesis to date. We found no evidence of SES moderation of genetic influence on test scores, suggesting that articulating gene-environment interactions for cognition is more complex and elusive than previously supposed.

Little Evidence That Socioeconomic Status Modifies Heritability of Literacy and Numeracy in Australia

Socioeconomic status (SES) has been found to moderate the influence of genes and the environment on cognitive ability, such that genetic influence is greater when SES is higher, and the shared environment is greater when SES is lower, but not in all Western countries. The effects of both family and school SES on the heritability of literacy and numeracy in Australian twins aged 8, 10, 12, and 14 years with 1,307, 1,235, 1,076, and 930 pairs at each age, respectively, were tested. Shared environmental influences on Grade 3 literacy were greater with low family SES, and no other moderating effects of SES were significant. These findings are contrasted with results from the United States and the United Kingdom.

Phenome-wide heritability analysis of the UK Biobank

Heritability estimation provides important information about the relative contribution of genetic and environmental factors to phenotypic variation, and provides an upper bound for the utility of genetic risk prediction models. Recent technological and statistical advances have enabled the estimation of additive heritability attributable to common genetic variants (SNP heritability) across a broad phenotypic spectrum. Here, we present a computationally and memory efficient heritability estimation method that can handle large sample sizes, and report the SNP heritability for 551 complex traits derived from the interim data release (152,736 subjects) of the large-scale, population-based UK Biobank, comprising both quantitative phenotypes and disease codes. We demonstrate that common genetic variation contributes to a broad array of quantitative traits and human diseases in the UK population, and identify phenotypes whose heritability is moderated by age (e.g., a majority of physical measures including height and body mass index), sex (e.g., blood pressure related traits) and socioeconomic status (education). Our study represents the first comprehensive phenome-wide heritability analysis in the UK Biobank, and underscores the importance of considering population characteristics in interpreting heritability.

Heritability of a trait refers to the proportion of phenotypic variation that is due to genetic variation among individuals. It provides important information about the genetic basis of complex traits and indicates whether a phenotype is an appropriate target for more specific statistical and molecular genetic analyses. Recent studies have leveraged the increasingly ubiquitous genome-wide data and documented the heritability attributable to common genetic variation captured by genotyping microarrays for a wide range of human traits. However, heritability is not a fixed property of a phenotype and can vary with population-specific differences in the genetic background and environmental variation. Here, using a computationally and memory efficient heritability estimation method, we report the heritability for a large number of traits derived from the large-scale, population-based UK Biobank, and, for the first time, demonstrate the moderating effect of three major demographic variables (age, sex and socioeconomic status) on heritability estimates derived from genome-wide common genetic variation. Our study represents the first comprehensive heritability analysis across the phenotypic spectrum in the UK Biobank.

Genetics and Organizational Behavior

Articles on the genetics of complex human behaviors and psychological traits provided in past volumes of journals published by Annual Reviews tended to adopt a pathological perspective and focused heavily on the disorders of human affect and behaviors. In our review, we expand our focus to the more general, nonclinical population, and in particular on the advances in the understanding of the genetics of attitudes and behaviors in work settings. We review the recent and emerging literature using a behavioral genetics approach to examine the influence of genetics on a wide array of important constructs in organizational behavior (OB) research and provide unique theoretical insights offered by this approach. We discuss practical implications and future research directions from a broad person-environment interactionist perspective by taking a genetics approach.

Large Cross-National Differences in Gene × Socioeconomic Status Interaction on Intelligence

A core hypothesis in developmental theory predicts that genetic influences on intelligence and academic achievement are suppressed under conditions of socioeconomic privation and more fully realized under conditions of socioeconomic advantage: a Gene × Childhood Socioeconomic Status (SES) interaction. Tests of this hypothesis have produced apparently inconsistent results. We performed a meta-analysis of tests of Gene × SES interaction on intelligence and academic-achievement test scores, allowing for stratification by nation (United States vs. non-United States), and we conducted rigorous tests for publication bias and between-studies heterogeneity. In U.S. studies, we found clear support for moderately sized Gene × SES effects. In studies from Western Europe and Australia, where social policies ensure more uniform access to high-quality education and health care, Gene × SES effects were zero or reversed.

Biometric Modeling of Gene-Environment Interplay: The Intersection of Theory and Method and Applications for Social Inequality

For more than a decade, biometric moderation models have been used to examine whether genetic and environmental influences on individual differences might vary within the population. These quantitative Gene × Environment interaction models have the potential to elucidate not only when genetic and environmental influences on a phenotype might differ, but also why, as they provide an empirical test of several theoretical paradigms that serve as useful heuristics to explain etiology-diathesis-stress, bioecological, differential susceptibility, and social control. In the current article, we review how these developmental theories align with different patterns of findings from statistical models of gene-environment interplay. We then describe the extant empirical evidence, using work by our own research group and others, to lay out genetically informative plausible accounts of how phenotypes related to social inequality-physical health and cognition-might relate to these theoretical models.

The Scarr-Rowe Interaction in Complete Seven-Year WISC Data from the Louisville Twin Study: Preliminary Report

We examine updated Wechsler IQ data in 7-year old twins from the Louisville Twin Study for evidence of an interaction between the heritability of IQ and socioeconomic status. Data records that had never been entered were recovered, allowing us to increase previously reported sample sizes by more than 20%. Twin families were assigned socioeconomic status scores using a Hollingshead index based on parental education and occupation. A structural equation model in which genetic and environmental variances were modeled as squared linear functions of SES provided ambiguous replication of earlier findings from the National Collaborative Perinatal Project: relations between SES and heritability for performance and full scale IQ were in the same direction as the previous report, but at p < 0.07. As was the case in Turkheimer et al. (Psychol Sci 14(6):623-628, 2003), no interaction was found for VIQ. These results cannot yet be taken as a definitive replication of Turkheimer et al. (Psychol Sci 14(6):623-628, 2003). Many more measurement occasions, subtests and environmental moderators remain to be analyzed.

Prenatal Programming of Postnatal Susceptibility to Memory Impairments: A Developmental Double Jeopardy

In the study reported here, we examined the effects of fetal exposure to a synthetic stress hormone (synthetic glucocorticoids) on children's susceptibility to postnatal sociodemographic adversity. We recruited children who were born healthy and at term. Twenty-six had been treated with steroid hormones (glucocorticoids) during the prenatal period, and 85 had not. Only children exposed to both prenatal stress hormones and postnatal sociodemographic adversity showed impaired performance on standardized tests of memory function. The association was specific to long-term memory. General intellectual functioning and expressive language were not affected by fetal glucocorticoid exposure. Results were independent of maternal intelligence and maternal depression at the time of the study. These findings are consistent with a vulnerability-stress model: Prenatal exposure to synthetic stress hormones is associated with increased susceptibility to subsequent adversity, with consequences for cognitive functioning that persist 6 to 10 years after birth.

Is education associated with improvements in general cognitive ability, or in specific skills?

Previous research has indicated that education influences cognitive development, but it is unclear what, precisely, is being improved. Here, we tested whether education is associated with cognitive test score improvements via domain-general effects on general cognitive ability (g), or via domain-specific effects on particular cognitive skills. We conducted structural equation modeling on data from a large (n = 1,091), longitudinal sample, with a measure of intelligence at age 11 years and 10 tests covering a diverse range of cognitive abilities taken at age 70. Results indicated that the association of education with improved cognitive test scores is not mediated by g, but consists of direct effects on specific cognitive skills. These results suggest a decoupling of educational gains from increases in general intellectual capacity.

The Glass is Half Full and Half Empty: A population-representative twin study testing if Optimism and Pessimism are distinct systems

Optimism and pessimism are associated with important outcomes including health and depression. Yet it is unclear if these apparent polar opposites form a single dimension or reflect two distinct systems. The extent to which personality accounts for differences in optimism/pessimism is also controversial. Here, we addressed these questions in a genetically informative sample of 852 pairs of twins. Distinct genetic influences on optimism and pessimism were found. Significant family-level environment effects also emerged, accounting for much of the negative relationship between optimism and pessimism, as well as a link to neuroticism. A general positive genetics factor exerted significant links among both personality and life-orientation traits. Both optimism bias and pessimism also showed genetic variance distinct from all effects of personality, and from each other.

Replication of a gene-environment interaction Via Multimodel inference: additive-genetic variance in adolescents' general cognitive ability increases with family-of-origin socioeconomic status

The present study of general cognitive ability attempts to replicate and extend previous investigations of a biometric moderator, family-of-origin socioeconomic status (SES), in a sample of 2,494 pairs of adolescent twins, non-twin biological siblings, and adoptive siblings assessed with individually administered IQ tests. We hypothesized that SES would covary positively with additive-genetic variance and negatively with shared-environmental variance. Important potential confounds unaddressed in some past studies, such as twin-specific effects, assortative mating, and differential heritability by trait level, were found to be negligible. In our main analysis, we compared models by their sample-size corrected AIC, and base our statistical inference on model-averaged point estimates and standard errors. Additive-genetic variance increased with SES-an effect that was statistically significant and robust to model specification. We found no evidence that SES moderated shared-environmental influence. We attempt to explain the inconsistent replication record of these effects, and provide suggestions for future research.

Cognitive deficits in pediatric-onset multiple sclerosis: what does the future hold?

Pediatric-onset multiple sclerosis is relatively rare and research regarding disease characteristics is in its infancy. Regardless, there are a growing number of studies finding early cognitive deficits in this population. There are some similarities in outcomes to those seen in the adult-onset multiple sclerosis population, but also several important differences. With specific regard to cognitive functioning in pediatric-onset multiple sclerosis, there is evidence of deficit in nearly a third of patients, with impairment primarily in areas of processing speed, visual-spatial processing and language. There are additional findings of fatigue and depression that impact functional outcomes requiring further attention in assessment and treatment considerations. This paper also explores other areas requiring increased focus, including treatment and outcomes, neuroimaging and additional disease-modifying factors (comorbidities, socioeconomic status, race and so on).

Low social status decreases the neural salience of unfairness

Social hierarchy exists in almost all social species and affects everything from resource allocation to the development of intelligence. Previous studies showed that status within a social hierarchy influences the perceived fairness of income allocation. However, the effect of one’s social status on economic decisions is far from clear, as are the neural processes underlying these decisions. In this study, we dynamically manipulated participants’ social status and analyzed their behavior as recipients in the ultimatum game (UG), during which event-related potentials (ERPs) were recorded. Behavioral results showed that acceptance rates for offers increased with the fairness level of offers. Importantly, participants were less likely to accept unfair offers when they were endowed with high status than with low status. In addition, cues indicating low status elicited a more positive P2 than cues indicating high status in an earlier time window (170–240 ms), and cues indicating high status elicited a more negative N400 than cues indicating low status in a later time window (350–520 ms). During the actual reception of offers, the late positivity potential (LPP, 400–700 ms) for unfair offers was more positive in the high status condition than in the low status condition, suggesting a decreased arousal for unfair offers during low status. These findings suggest a strong role of social status in modulating individual behavioral and neural responses to fairness.

Chimpanzee intelligence is heritable

The role that genes play in human intelligence or IQ has remained a point of significant scientific debate dating back to the time of Galton [1]. It has now become increasingly clear that IQ is heritable in humans, but these effects can be modified by nongenetic mechanisms [2-4]. In contrast to human IQ, until recently, views of learning and cognition in animals have largely been dominated by the behaviorist school of thought, originally championed by Watson [5] and Skinner [6]. A large body of accumulated research now demonstrates a variety of cognitive abilities in nonhuman animals and challenges traditional behaviorist interpretations of performance [7, 8]. This, in turn, has led to a renewed interest in the role that social and biological factors might play in explaining individual and phylogenetic differences in cognition [9]. Specifically, aside from early attempts to selectively breed for learning skills in rodents [10-12], studies examining the role that genetic factors might play in individual variation in cognitive abilities in nonhuman animals, particularly nonhuman primates, are scarce. Here, we utilized a modified Primate Cognitive Test Battery [13] in conjunction with quantitative genetic analyses to examine whether cognitive performance is heritable in chimpanzees. We found that some but not all cognitive traits were significantly heritable in chimpanzees. We further found significant genetic correlations between different dimensions of cognitive functioning, suggesting that the genes that explain the variability of one cognitive trait might also explain that of other cognitive traits.

Genetic and Environmental Influences on Cognition Across Development and Context

Genes account for between approximately 50% and 70% of the variation in cognition at the population level. However, population-level estimates of heritability potentially mask marked subgroup differences. We review the body of empirical evidence indicating that (a) genetic influences on cognition increase from infancy to adulthood, and (b) genetic influences on cognition are maximized in more advantaged socioeconomic contexts (i.e., a Gene × Socioeconomic Status interaction). We discuss potential mechanisms underlying these effects, particularly transactional models of cognitive development. Transactional models predict that people in high-opportunity contexts actively evoke and select positive learning experiences on the basis of their genetic predispositions; these learning experiences, in turn, reciprocally influence cognition. The net result of this transactional process is increasing genetic influence with increasing age and increasing environmental opportunity.