Change and stability in the association of parents' education with children's intelligence

Does Schooling Improve Cognitive Abilities at Older Ages? Causal Evidence From Nonparametric Bounds

We revisit much-investigated relationships between schooling and health, focusing on schooling impacts on cognitive abilities at older ages using the Harmonized Cognition Assessment Protocol in the Health and Retirement Study (HRS) and a bounding approach that requires relatively weak assumptions. Our estimated upper bounds on the population average effects indicate potentially large causal effects of increasing schooling from primary to secondary. Yet, these upper bounds are smaller than many estimates from studies of causal schooling impacts on cognition using compulsory schooling laws. We also cannot rule out small and null effects at this margin. However, we find evidence for positive causal effects on cognition of increasing schooling from secondary to tertiary. We replicate findings from the HRS using data on older adults from the Midlife in United States Development Study Cognitive Project. We further explore possible mechanisms behind the schooling effect (e.g., health, socioeconomic status, occupation, and spousal schooling), finding suggestive evidence of effects through such mechanisms.

Association between parental education level and intelligence quotient of children referred to the mental healthcare system: a cross-sectional study in Poland

Considering the gap in understanding of the link between parental education and child intelligence quotient (IQ), our study aimed to investigate the association between parental education and the IQ of children referred to the mental healthcare system, explore which parent's education level is more influential, and examine the impact of the child's age and sex on these relationships. This cross-sectional study included 80,303 children aged 3-18 years who were referred to the mental healthcare system between 2018 and 2023. We predefined IQ composite score (Full IQ Scale), as measured by the Stanford Binet 5 Intelligence Scale, Fifth Edition (SB-5) as the primary outcome; the remaining SB-5 composite scores were the secondary outcomes. Linear regression analysis was performed using staircase coding for ordinal predictors with several binary independent variables. A significant correlation was found between parental education levels and IQ of the sampled children, with higher levels of parents' education predicting higher IQ scores, particularly with mother's education explaining 18.23% of the variance in children's overall intelligence. No significant interaction was observed between parental education and child's sex in predicting child IQ. However, a significant interaction was observed with age, showing that IQ decreases with age in children of parents with lower education, while it increases with age in children of parents with higher education. Our study underscores the pivotal influence of parental education on the IQ levels of children referred to mental healthcare services. Maternal education level was a stronger predictor of child IQ, potentially because mothers tend to be the primary caregivers. These findings suggest the need for targeted support programs for caregivers, particularly those with lower education levels, to facilitate the early detection of developmental challenges. Integrated education and healthcare efforts are crucial for equitable mental healthcare access.

The Role of Parental Education, Intelligence, and Personality on the Cognitive Abilities of Gifted Children

Several studies have indicated that parental education predicts children's intelligence. In contrast, fewer studies have simultaneously analyzed the role of parental intelligence, education, and personality in shaping their children's giftedness. This study investigated the effects of parental education, cognitive abilities (based on CHC theory), and personality traits (based on the Five-Factor Model) on the expression of gifted children's cognitive abilities. Sixty-five gifted children (IQ ≥ 120) aged 6 to 14 years (M = 9.91 years; SD = 2.24 years) were assessed using the WISC-IV, while parents (65 mothers, M = 44.00 years; SD = 4.20 years, and 61 fathers, M = 45.70 years; SD = 5.40 years) completed the WAIS-IV and the Big-Five Inventory. The results indicated that maternal education was a key predictor of children's Verbal Comprehension Index (VCI) in bivariate analyses, though its effect was not robust in multivariate models. Children's Perceptual Reasoning Index (PRI) was associated with maternal conscientiousness, and fathers' short-term memory (Gsm) emerged as the primary predictor of children's Working Memory Index (WMI). Maternal processing speed (Gs) was the strongest predictor of children's Processing Speed Index (PSI) across both bivariate and multivariate analyses. While personality traits, such as maternal conscientiousness, played a role in facilitating visual-spatial reasoning, their effects were weaker compared to cognitive and educational factors. The findings obtained, which are only partly consistent with data in the literature, highlight the domain-specific influence of parental characteristics on children's giftedness and underscore the need for further research into the interplay of genetic, cognitive, and environmental factors.

Teachers' and Parents' Assessments of Primary School Children's Intellectual Investment as Predictors of Change in Need for Cognition

The present study investigated whether parents' and teachers' evaluations of children's intellectual investment would predict a change in children's need for cognition (NFC) over one year. An exploratory look at how teachers' evaluations are predicted by a range of factors was also taken. N = 565 third-graders (298 girls; Mage = 8.40, SD = 0.59) and teachers (N = 39) were surveyed in 2021 and 2022. The parents (N = 452) provided the data in 2021. Longitudinal data were analyzed by means of latent change score models (LCSMs). Changes in the teachers' evaluations and in the children's cognitive engagement differed between the children. However, there was no effect of the parents' or teachers' assessments on the development of the children's NFC. The change in the teachers' assessment was negatively related to their initial judgment and the children's age; it was positively related to the pupils' fluid intelligence. The results and implications are discussed.

Longitudinal associations between paternal mental health and child behavior and cognition in middle childhood

Introduction

Paternal mental health has been associated with adverse consequences on offspring psychosocial development, and family environmental factors may partly explain those associations. To clarify this, we need comprehensive prospective studies, particularly in middle-childhood when the child enters school and is expected to make use of behavioral and cognitive skills as part of their interactions and learning.

Method

Using data from a sub-sample of the prospective 3D birth cohort study comprised of mother-father-child triads, and a follow-up of the parents and the children at 6-8 years of age (n = 61; 36 boys, 25 girls), we examined whether paternal anxious and depressive symptoms measured during the pregnancy period (i.e., prenatally) or concurrently when the child was assessed at 6-8 years old were associated with children's cognition/behavior.

Results

In contrast to our hypotheses, we found that greater prenatal paternal depressive symptoms predicted fewer child behavioral difficulties; and that greater concurrent childhood paternal depression or anxiety symptoms were associated with higher child full-scale IQ, controlling for the equivalent maternal mental health assessment and parental education. Father parenting perception did not mediate these associations, nor were they moderated by maternal mental health at the concurrent assessment, or paternal ratings of marital relationship quality.

Discussion

These findings suggest that higher symptoms of paternal mental health symptoms are associated with fewer child behavioral difficulties and higher cognitive performance in middle childhood. Potential clinical implications and future research directions are discussed.

Do childhood depressive symptoms interfere with intelligence in adulthood?

OBJECTIVE

To investigate the effects of depressive symptoms in childhood on the intellectual development of young adults.

METHODS

Study conducted with a birth cohort of São Luís, Maranhão, Brazil, composed of 339 participants evaluated between 7 and 9 years and between 18 and 19 years. Structural equation modeling (young adult education, sex, race/color) and childhood variables (nutritional status, depressive symptoms, cognitive function, head of household's and mother's education, family income) were used. In addition, head of household's occupation, mother's age, and presence of partner were tested as determinants of adults' intelligence quotient (IQ).

RESULTS

Presence of depressive symptoms in childhood triggered a reduction of 0.342 in standard deviation (SD) and -3.83 points in the average IQ of adults (p-value < 0.001). Cognitive function in childhood had a total and direct positive effect (standardized coefficient [SC] = 0.701; p-value < 0.001) on IQ, increasing 7.84 points with each increase in level. A positive indirect effect of child nutritional status (SC = 0.194; p-value = 0.045), head of household's (SC = 0.162; p-value = 0.036), and mother's education was identified, the latter mediated by cognitive function in childhood (SC = 0.215; p-value = 0.012) on the IQ of young people.

CONCLUSION

Presence of depressive symptoms in childhood triggered a long-term negative effect on intelligence, reducing the IQ score in adulthood.

Evidence of correlations between human partners based on systematic reviews and meta-analyses of 22 traits and UK Biobank analysis of 133 traits

Positive correlations between mates can increase trait variation and prevalence, as well as bias estimates from genetically informed study designs. While past studies of similarity between human mating partners have largely found evidence of positive correlations, to our knowledge, no formal meta-analysis has examined human partner correlations across multiple categories of traits. Thus, we conducted systematic reviews and random-effects meta-analyses of human male-female partner correlations across 22 traits commonly studied by psychologists, economists, sociologists, anthropologists, epidemiologists and geneticists. Using ScienceDirect, PubMed and Google Scholar, we incorporated 480 partner correlations from 199 peer-reviewed studies of co-parents, engaged pairs, married pairs and/or cohabitating pairs that were published on or before 16 August 2022. We also calculated 133 trait correlations using up to 79,074 male-female couples in the UK Biobank (UKB). Estimates of the 22 mean meta-analysed correlations ranged from rmeta = 0.08 (adjusted 95% CI = 0.03, 0.13) for extraversion to rmeta = 0.58 (adjusted 95% CI = 0.50, 0.64) for political values, with funnel plots showing little evidence of publication bias across traits. The 133 UKB correlations ranged from rUKB = -0.18 (adjusted 95% CI = -0.20, -0.16) for chronotype (being a 'morning' or 'evening' person) to rUKB = 0.87 (adjusted 95% CI = 0.86, 0.87) for birth year. Across analyses, political and religious attitudes, educational attainment and some substance use traits showed the highest correlations, while psychological (that is, psychiatric/personality) and anthropometric traits generally yielded lower but positive correlations. We observed high levels of between-sample heterogeneity for most meta-analysed traits, probably because of both systematic differences between samples and true differences in partner correlations across populations.

Neurocognition as a biomarker in the rare autonomic disorders of CCHS and ROHHAD

PURPOSE

Congenital central hypoventilation syndrome (CCHS) and rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation (ROHHAD) are rare disorders of autonomic regulation with risk for disrupted neurocognitive development. Our aim is to summarize research on neurocognitive outcomes in these conditions, advance understanding of how to best support these individuals throughout development, and facilitate future research.

METHODS

We conducted a narrative review of literature on neurocognitive outcomes in CCHS and ROHHAD, supplemented with previously unpublished data from patients with CCHS and ROHHAD at our Center for Autonomic Medicine in Pediatrics (CAMP).

RESULTS

Individuals with CCHS and ROHHAD experience a wide range of neurocognitive functioning ranging from above average to below average, but are at particular risk for difficulties with working memory, processing speed, perceptual reasoning, and visuographic skills. An assessment framework emphasizing fluid cognition seems especially appropriate for these conditions. Owing to small cohorts and varied methods of data collection, it has been difficult to identify associations between disease factors (including CCHS PHOX2B genotypes) and cognitive outcomes. However, results suggest that early childhood is a period of particular vulnerability, perhaps due to the disruptive impact of recurrent intermittent hypoxic episodes on brain and cognitive development.

CONCLUSION

Neurocognitive monitoring is recommended as a component of routine clinical care in CCHS and ROHHAD as a marker of disease status and to ensure that educational support and disability accommodations are provided as early as possible. Collaborative efforts will be essential to obtain samples needed to enhance our understanding of neurocognitive outcomes in CCHS and ROHHAD.

Association of Dental Fluorosis and Urinary Fluoride with Intelligence among Schoolchildren

Fluoride is present naturally in water and has been used worldwide for the prevention of caries. Several studies conducted in high water fluoride or endemic fluorosis areas reported that fluoride adversely affected children's cognitive function, but some studies had negative findings. This study aimed to assess the relationship between urinary fluoride, dental fluorosis, and intelligence among schoolchildren living in communities with non-fluoridated drinking water. This cross-sectional study was conducted on 562 children aged 6-12 years in Taichung, Taiwan. Each child's urinary fluoride level was determined by a fluoride-ion-selective electrode, and the dental fluorosis condition was evaluated according to the criteria of Dean's Index. The Raven's Colored Progressive Matrices-Parallel and Standard Progressive Matrices-Parallel were used to assess children's intelligence. The results showed that the mean (±standard deviation) urinary fluoride concentrations were 0.40 ± 0.27 mg/L (0.43 ± 0.23 mg/g creatinine) among participants. The prevalence of dental fluorosis was 23.67%. After extensive evaluation of potential confounders, dental fluorosis and urinary fluoride were not associated with intelligence quotient (IQ) scores or grades in the regression models. In conclusion, dental fluorosis and urinary fluoride levels were not significantly related to the IQ of schoolchildren living in areas with low drinking water fluoride.

Parental education, cognition and functional connectivity of the salience network

The aim was to investigate the association of parental education at birth with cognitive ability in childhood and young adulthood and determine, whether functional connectivity of the salience network underlies this association. We studied participants of the Czech arm of the European Longitudinal Study of Pregnancy and Childhood who underwent assessment of their cognitive ability at age 8 (Wechsler Intelligence Scale for Children) and 28/29 years (Wechsler Adult Intelligence Scale) and measurement with resting state functional MRI at age 23/24. We estimated the associations of parental education with cognitive ability and functional connectivity between the seeds in the salience network and other voxels in the brain. We found that lower education of both mothers and fathers was associated with lower verbal IQ, performance IQ and full-scale IQ of the offspring at age 8. Only mother´s education was associated with performance IQ at age 28/29. Lower mother´s education correlated with greater functional connectivity between the right rostral prefrontal cortex and a cluster of voxels in the occipital cortex, which, in turn, was associated with lower performance IQ at age 28/29. We conclude that the impact of parental education, particularly father´s, on offspring´s cognitive ability weakens during the lifecourse. Functional connectivity between the right rostral prefrontal cortex and occipital cortex may be a biomarker underlying the transmission of mother´s education on performance IQ of their offspring.

The Evolution of Intelligence: Analysis of the Journal of Intelligence and Intelligence

What are the current trends in intelligence research? This parallel bibliometric analysis covers the two premier journals in the field: Intelligence and the Journal of Intelligence (JOI) between 2013 and 2022. Using Scopus data, this paper extends prior bibliometric articles reporting the evolution of the journal Intelligence from 1977 up to 2018. It includes JOI from its inception, along with Intelligence to the present. Although the journal Intelligence's growth has declined over time, it remains a stronghold for traditional influential research (average publications per year = 71.2, average citations per article = 17.07, average citations per year = 2.68). JOI shows a steady growth pattern in the number of publications and citations (average publications per year = 33.2, average citations per article = 6.48, total average citations per year = 1.48) since its inception in 2013. Common areas of study across both journals include cognitive ability, fluid intelligence, psychometrics-statistics, g-factor, and working memory. Intelligence includes core themes like the Flynn effect, individual differences, and geographic IQ variability. JOI addresses themes such as creativity, personality, and emotional intelligence. We discuss research trends, co-citation networks, thematic maps, and their implications for the future of the two journals and the evolution and future of the scientific study of intelligence.

Association between Elevated Iodine Intake and IQ among School Children in Portugal

The goal of this work was to examine whether elevated iodine intake was associated with adverse effects on IQ among school-age children in Portugal. In a representative sample of children from the north of the country, IQ percentiles by age (assessed with Raven’s Colored Progressive Matrices) were dichotomized to <50 (“below-average” IQs) and ≥50. Morning urine iodine concentrations, corrected for creatinine, were dichotomized to <250 µg/g and ≥250 µg/g, according to the European Commission/Scientific Committee on Food’s tolerable upper level of daily iodine intake for young children. Data were examined with Chi-square tests, logistic regression, and GLM univariate analysis. The sample (N = 1965) was classified as generally iodine-adequate (median urinary iodine concentration = 129 µg/L; median iodine-to-creatinine ratio = 126 µg/g) according to the WHO’s criteria. A greater proportion of children in the ≥250 µg/g group had below-average IQs, compared to children with less than 250 µg/g (p = 0.037), despite a sizable (though non-significant) proportion of children in the less-than-250 µg/g group also presenting below-average IQs, at the bottom of the iodine distribution (<50 µg/g). The proportion of below-average IQs increased with increasingly elevated iodine concentrations (p = 0.047). The association remained significant after the adjustment for confounders, with the elevated iodine group showing increased odds of having below-average IQs when compared with the non-elevated iodine group (OR 1.55; 95% CI 1.11−2.17; p = 0.011). Consistently, the former group presented a lower mean IQ than the latter (p = 0.006). High iodine intake was associated with lower IQs even in a population classified as iodine-adequate. These results bear on child cognition and on initiatives involving iodine supplementation.