The Flynn effect: a meta-analysis

Trends in Intracranial and Cerebral Volumes of Framingham Heart Study Participants Born 1930 to 1970

Importance

Human brain development and maintenance is under both genetic and environmental influences that likely affect later-life dementia risk.

Objective

To examine environmental influences by testing whether time-dependent secular differences occurred in cranial and brain volumes and cortical thickness over birth decades spanning 1930 to 1970.

Design, Setting, and Participants

This cross-sectional study used data from the community-based Framingham Heart Study cohort for participants born in the decades 1930 to 1970. Participants did not have dementia or history of stroke and had magnetic resonance imaging (MRI) obtained from March 18, 1999, to November 15, 2019. The final analysis dataset was created in October 2023.

Exposure

Years of birth ranging from 1925 to 1968.

Main Measures

Cross-sectional analysis of intracranial, cortical gray matter, white matter, and hippocampal volumes as well as cortical surface area and cortical thickness. The secular measure was the decade in which the participant was born. Covariates included age at MRI and sex.

Results

The main study cohort consisted of 3226 participants with a mean (SD) age of 57.7 (7.8) years at the time of their MRI. A total of 1706 participants were female (53%) and 1520 (47%) were male. The birth decades ranged from the 1930s to 1970s. Significant trends for larger intracranial, hippocampal, and white matter volumes and cortical surface area were associated with progressive birth decades. Comparing the 1930s birth decade to the 1970s accounted for a 6.6% greater volume (1234 mL; 95% CI, 1220-1248, vs 1321 mL; 95% CI, 1301-1341) for ICV, 7.7% greater volume (441.9 mL; 95% CI, 435.2-448.5, vs 476.3 mL; 95% CI, 467.0-485.7) for white matter, 5.7% greater value (6.51 mL; 95% CI, 6.42-6.60, vs 6.89 mL; 95% CI, 6.77-7.02) for hippocampal volume, and a 14.9% greater value (1933 cm2; 95% CI, 1908-1959, vs 2222 cm2; 95% CI, 2186-2259) for cortical surface area. Repeat analysis applied to a subgroup of 1145 individuals of similar age range born in the 1940s (mean [SD] age, 60.0 [2.8] years) and 1950s (mean [SD] age, 59.0 [2.8] years) resulted in similar findings.

Conclusion and Relevance

In this study, secular trends for larger brain volumes suggested improved brain development among individuals born between 1930 and 1970. Early life environmental influences may explain these results and contribute to the declining dementia incidence previously reported in the Framingham Heart Study cohort.

A Review of Screeners to Identify Risk of Developmental Language Disorder

PURPOSE

This review aims to comprehensively summarize, compare, and evaluate screeners used to identify risk for developmental language disorder (DLD), a common learning disability that is underidentified. Screening for DLD is a cost-effective way to identify children in need of further assessment and, in turn, provides much needed supports.

METHOD

We identified 15 commercially available English language DLD screeners in North America. We then characterized each screener on 27 aspects in three domains, including (a) accessibility information (acronym, subtest, website, cost, materials included, publish year, examiner qualification, age range, administration time, and administration format), (b) usability features (dialect compatibility, progress monitoring function, actionable follow-up instruction, group assessment capability, and online administration availability), and (c) technical standards (the availability of a technical manual, conceptual definition, the sample size used in classification accuracy calculation, sample distribution, year of sample collection, outcome measure, sample base rate, cutoff score, sensitivity, specificity, positive predictive value, and negative predictive value).

RESULTS

We obtained sufficient accessibility information from 14 out of 15 (93%) screeners. In contrast, none of the screeners (0%) included comprehensive usability features. Ten screeners (67%) included a range of classification accuracy (70%-100% sensitivity and 68%-90% specificity). We provided areas of strength and weakness for each screener as a quick reference for users and generated screener recommendations for five practical scenarios.

CONCLUSIONS

Our findings presented some DLD screeners that meet most standards and highlight numerous areas for improvement, including improving classification accuracy and clarifying follow-up instructions for children who are identified with DLD risk. Screening for DLD is critical to provide timely early identification, intervention, and classroom support, which in turn facilitates student outcomes.

Secular trends in physical growth, biological maturation, and intelligence in children and adolescents born between 1978 and 1993

Introduction

Human physical growth, biological maturation, and intelligence have been documented as increasing for over 100 years. Comparing the timing of secular trends in these characteristics could provide insight into what underlies them. However, they have not been examined in parallel in the same cohort during different developmental phases. Thus, the aim of this study was to examine secular trends in body height, weight, and head circumference, biological maturation, and intelligence by assessing these traits concurrently at four points during development: the ages of 4, 9, 14, and 18 years.

Methods

Data derived from growth measures, bone age as an indicator of biological maturation, and full-scale intelligence tests were drawn from 236 participants of the Zurich Longitudinal Studies born between 1978 and 1993. In addition, birth weight was analyzed as an indicator of prenatal conditions.

Results

Secular trends for height and weight at 4 years were positive (0.35 SD increase per decade for height and an insignificant 0.27 SD increase per decade for weight) and remained similar at 9 and 14 years (height: 0.46 SD and 0.38 SD increase per decade; weight: 0.51 SD and 0.51 SD increase per decade, respectively) as well as for weight at age 18 years (0.36 SD increase per decade). In contrast, the secular trend in height was no longer evident at age 18 years (0.09 SD increase per decade). Secular trends for biological maturation at 14 years were similar to those of height and weight (0.54 SD increase per decade). At 18 years, the trend was non-significant (0.38 SD increase per decade). For intelligence, a positive secular trend was found at 4 years (0.54 SD increase per decade). In contrast, negative secular trends were observed at 9 years (0.54 SD decrease per decade) and 14 years (0.60 SD decrease per decade). No secular trend was observed at any of the four ages for head circumference (0.01, 0.24, 0.17, and - 0.04 SD increase per decade, respectively) and birth weight (0.01 SD decrease per decade).

Discussion

The different patterns of changes in physical growth, biological maturation, and intelligence between 1978 and 1993 indicate that distinct mechanisms underlie these secular trends.

Generalizability of the Swedish WISC-V to the Finland-Swedish minority - the FinSwed study

International guidelines highlight the importance of using appropriate and culturally fair test materials when conducting clinical psychological assessments. In the present study, the generalizability of the Swedish WISC-V with Scandinavian normative data was explored in 6-16-year-old Swedish-speaking children in Finland (N = 134), as no local test versions or norms are available for this minority. First, metric measurement invariance was established, i.e., the constructs measured were equivalent between the standardization data and the present sample. Second, the performance of this minority group on the Swedish WISC-V was compared to the Scandinavian normative mean. The findings showed that the Finland-Swedish children performed overall higher than the normative mean on the Swedish WISC-V, with an FSIQ of 103. The performance was significantly higher also in the indexes VSI, FRI, and WMI as well as in several subtests. However, in the subtest Vocabulary, the Finland-Swedish children achieved significantly lower scores than the Scandinavian mean. Further analyses showed significant associations between cognitive performance and age as well as parental education. For the VCI and the FSIQ, performance increased significantly with age, despite the use of age-standardized scaled scores. The general high performance was suggested to relate to the overall high educational level of the Finland-Swedes as well as to other cultural and test-related factors. The results have implications for clinicians conducting assessments with this minority, but also highlight the importance of establishing test fairness by validating tests when used in different cultural groups.

Maximizing utility of neuropsychological measures in sex-specific predictive models of incident Alzheimer's disease in the Framingham Heart Study

INTRODUCTION

Sex differences in neuropsychological (NP) test performance might have important implications for the diagnosis of Alzheimer's disease (AD). This study investigates sex differences in neuropsychological performance among individuals without dementia at baseline.

METHODS

Neuropsychological assessment data, both standard test scores and process coded responses, from Framingham Heart Study participants were analyzed for sex differences using regression model and Cox proportional hazards model. Optimal NP profiles were identified by machine learning methods for men and women.

RESULTS

Sex differences were observed in both summary scores and composite process scores of NP tests in terms of adjusted means and their associations with AD incidence. The optimal NP profiles for men and women have 10 and 8 measures, respectively, and achieve 0.76 mean area under the curve for AD prediction.

DISCUSSION

These results suggest that NP tests can be leveraged for developing more sensitive, sex-specific indices for the diagnosis of AD.

The Effect of Income and Wealth on Behavioral Strategies, Personality Traits, and Preferences

Individuals living in either harsh or favorable environments display well-documented psychological and behavioral differences. For example, people in favorable environments tend to be more future-oriented, trust strangers more, and have more explorative preferences. To account for such differences, psychologists have turned to evolutionary biology and behavioral ecology, in particular, the literature on life-history theory and pace-of-life syndrome. However, critics have found that the theoretical foundations of these approaches are fragile and that differences in life expectancy cannot explain vast psychological and behavioral differences. In this article, we build on the theory of optimal resource allocation to propose an alternative framework. We hypothesize that the quantity of resources available, such as income, has downstream consequences on psychological traits, leading to the emergence of behavioral syndromes. We show that more resources lead to more long-term orientation, more tolerance of variance, and more investment in low marginal-benefit needs. At the behavioral level, this translates, among others, into more large-scale cooperation, more investment in health, and more exploration. These individual-level differences in behavior, in turn, account for cultural phenomena such as puritanism, authoritarianism, and innovation.

Cross-sectional and longitudinal assessment of cognitive development in Williams syndrome

Williams syndrome (WS) is a rare genetic syndrome. As with all rare syndromes, obtaining adequately powered sample sizes is a challenge. Here we present legacy data from seven UK labs, enabling the characterisation of cross-sectional and longitudinal developmental trajectories of verbal and non-verbal development in the largest sample of individuals with WS to-date. In Study 1, we report cross-sectional data between N = 102 and N = 209 children and adults with WS on measures of verbal and non-verbal ability. In Study 2, we report longitudinal data from N = 17 to N = 54 children and adults with WS who had been tested on at least three timepoints on these measures. Data support the WS characteristic cognitive profile of stronger verbal than non-verbal ability, and shallow developmental progression for both domains. Both cross-sectional and longitudinal data demonstrate steeper rates of development in the child participants than the adolescent and adults in our sample. Cross-sectional data indicate steeper development in verbal than non-verbal ability, and that individual differences in the discrepancy between verbal and non-verbal ability are largely accounted for by level of intellectual functioning. A diverging developmental discrepancy between verbal and non-verbal ability, whilst marginal, is not mirrored statistically in the longitudinal data. Cross-sectional and longitudinal data are discussed with reference to validating cross-sectional developmental patterns using longitudinal data and the importance of individual differences in understanding developmental progression.

Assessment of Specific Learning Disabilities and Intellectual Disabilities

We review literature related to the assessment and identification of Specific Learning Disabilities (SLD) and Intellectual Disabilities (ID). SLD and ID are the only two disorders requiring psychometric test performance for identification within the group of neurodevelopmental disorders in Diagnostic and Statistical Manual - 5. SLD and ID are considered exclusionary of one another, but the processes for assessment and identification of each disorder vary. There is controversy about the identification and assessment methods for SLD, with little consensus. Unlike ID, SLD is weakly related to full-scale IQ, and there is insufficient evidence that the routine assessment of IQ or cognitive skills adds value to SLD identification and treatment. We have proposed a hybrid method based on the assessment of low achievement with norm-referenced tests, instructional response, and other disorders and contextual factors that may be comorbid or contraindicative of SLD. In contrast to SLD, there is strong consensus for a three-prong definition for the identification and assessment of ID: (a) significantly subaverage IQ, (b) adaptive behavior deficits that interfere with independent living in the community, and (c) age of onset in the developmental period. For both SLD and ID, we identify areas of controversy and best practices for identification and assessment.

The Association between Education and Cognitive Performance Varies at Different Levels of Cognitive Performance: A Quantile Regression Approach

INTRODUCTION

Educational differences in cognitive performance among older adults are well documented. Studies that explore this association typically estimate a single average effect of education on cognitive performance. We argue that the processes that contribute to the association between education and cognitive performance are unlikely to have equal effects at all levels of cognitive performance. In this study, we employ an analytical approach that enables us to go beyond averages to examine the association between education and five measures of global and domain-specific cognitive performance across the outcome distributions.

METHODS

This cross-sectional study included 1,780 older adults aged 58-68 years from the Longitudinal Aging Study Amsterdam. Conditional quantile regression was used to examine variation across the outcome distribution. Cognitive outcomes included Mini-Mental State Examination (MMSE) score, crystallized intelligence, information processing speed, episodic memory, and a composite score of global cognitive performance.

RESULTS

The results showed that the associations between education and different cognitive measures varied across the outcome distributions. Specifically, we found that education had a stronger association with crystallized intelligence, MMSE, and a composite cognitive performance measure in the lower tail of performance distributions. The associations between education and information processing speed and episodic memory were uniform across the outcome distributions.

CONCLUSION

Larger associations between education and some domains of cognitive performance in the lower tail of the performance distributions imply that inequalities are primarily generated among individuals with lower performance rather than among average and high performers. Additionally, the varying associations across some of the outcome distributions indicate that estimating a single average effect through standard regression methods may overlook variations in cognitive performance between educational groups. Future studies should consider heterogeneity across the outcome distribution.

Regression-based normative data for the D-KEFS Color-Word Interference Test in Norwegian adults ages 20-85

Objective: The Delis-Kaplan Executive Function System (D-KEFS) Color-Word-Interference Test (CWIT; AKA Stroop test) is a widely used measure of processing speed and executive function. While test materials and instructions have been translated to Norwegian, only American age-adjusted norms from D-KEFS are available in Norway. We here develop norms in a sample of 1011 Norwegians between 20 and 85 years. We provide indexes for stability over time and assess demographic adjustments applying the D-KEFS norms. Method: Participants were healthy Norwegian adults from Center for Lifespan Changes in Brain and Cognition (LCBC) (n = 899), the Dementia Disease Initiation (n = 77), and Oslo MCI (n = 35). Using regression-based norming, we estimated linear and non-linear effects of age, education, and sex on the CWIT 1-4 subtests. Stability over time was assessed with intraclass correlation coefficients (ICC). The normative adjustment of the D-KEFS norms was assessed with linear regression models. Results: Increasing age was associated with slower completion on all CWIT subtests in a non-linear fashion (accelerated lowering of performance with older age). Women performed better on CWIT-1&3. Higher education predicted faster completion time on CWIT-3&4. The original age-adjusted norms from D-KEFS did not adjust for sex or education. Furthermore, we observed significant, albeit small effects of age on all CWIT subtests. ICC analyses indicated moderate to good stability over time. Conclusion: We present demographically adjusted regression-based norms and stability indexes for the D-KEFS CWIT subtests. US D-KEFS norms may be inaccurate for Norwegians with high or low educational attainment, especially women.

Long-term neurocognitive outcomes in 204 single-suture craniosynostosis patients

PURPOSE

Craniosynostosis, which describes premature fusion of one or more cranial sutures, has been associated with a variety of neurocognitive deficits. We sought to explore the cognitive profiles of the various types of single-suture, non-syndromic craniosynostosis (NSC).

METHODS

A retrospective review of children 6-18 years old with surgically corrected NSC who underwent neurocognitive testing (Weschler Abbreviated Scale of Intelligence, Beery-Buktenica Developmental Test of Visuomotor Integration) from the years 2014-2022 was conducted.

RESULTS

204 patients completed neurocognitive testing (139 sagittal, 39 metopic, 22 unicoronal, 4 lambdoid suture). 110 (54%) of the cohort was male, and 150 (74%) were White. Mean IQ was 106.10±14.01 and mean age at surgery and testing were 9.0±12.2 months and 10.9±4.0 years, respectively. Sagittal synostosis was associated with higher scores than metopic synostosis, with significant differences in verbal IQ (109.42±15.76 vs 101.37±10.41), full-scale IQ (108.32±14.44 vs 100.05±11.76), visuomotor integration (101.62±13.64 vs 92.44±12.07), visual perception (103.81±12.42 vs 95.87±11.23), and motor coordination (90.45±15.60 vs 84.21±15.44). Sagittal synostosis was associated with significantly higher scores for visuomotor integration (101.62±13.64 vs 94.95±10.24) and visual perception (103.81±12.42 vs 94.82±12.75) than unicoronal synostosis.

CONCLUSIONS

Compared to patients with sagittal synostosis, patients with metopic synostosis exhibited lower scores in verbal IQ, full-scale IQ, visuomotor integration, visual perception, and motor control after surgical correction. Despite surgical correction for premature metopic suture fusion, the effect on the adjacent frontal lobe and white matter connections to other regions of the brain may have a lasting functional impact. Patients with unicoronal synostosis exhibited lower visuomotor integration and visual perception scores.

Secular trends in motor performance in Swiss children and adolescents from 1983 to 2018

Introduction

Environmental changes, including globalization, urbanization, social and cultural changes in society, and exposure to modern digital technology undoubtedly have an impact on children’s activity and lifestyle behavior. In fact, marked reductions in children’s physical activity levels have been reported over the years and sedentary behavior has increased around the world. The question arises whether these environmental changes had an impact on general motor performance in children and adolescents. The study aimed to investigate secular trends of motor performance in Swiss children and adolescents, aged between 7 and 18 years, over a period of 35 years from 1983 to 2018.

Methods

Longitudinal data on the five motor components of the Zurich Neuromotor Assessment (ZNA) – pure motor (PM), fine motor (FM), dynamic balance (DB), static balance (SB), and contralateral associated movements (CAM) – were pooled with cross-sectional data on PM and FM from eight ZNA studies between 1983 and 2018. Regression models were used to estimate the effect of the year of birth on motor performance and body mass index (BMI) measurements. Models were adjusted for age, sex, and socioeconomic status.

Results

The secular trend estimates in standard deviation scores (SDS) per 10 years were − 0.06 [−0.33; 0.22, 95% Confidence Interval] for PM, −0.11 [−0.41; 0.20] for FM, −0.38 [−0.66; −0.09] for DB (−0.42 when controlled for BMI), −0.21 [−0.47; 0.06] for SB, and − 0.01 [−0.32; 0.31] for CAM. The mean change in BMI data was positive with 0.30 SDS [0.07; 0.53] over 10 years.

Discussion

Despite substantial societal changes since the 1980s, motor performance has remained relatively stable across generations. No secular trend was found in FM, PM, SB, and CAM over a period of 35 years. A secular trend in DB was present independent of the secular trend in body mass index.

It Runs in the Family: Testing for Longitudinal Family Flynn Effects

The Flynn effect refers to increases over time in measured (particularly fluid) intelligence of approximately 3 IQ points per decade. We define the Flynn effect at the family level, using longitudinal data and two new family-level cohort definitions. Multilevel growth curve analyses of the National Longitudinal Survey of Youth 1979 data showed that children in families with later-born mothers had higher average PIAT math scores, and lower average reading comprehension scores and growth, in young and middle childhood. Children in families where the first child was born later had higher average PIAT math, reading recognition, and reading comprehension scores, as well as larger developmental growth. The latter family-level Flynn effects were of higher magnitudes than the usual individual-level Flynn effect found in previous studies. Our results, showing family level-intercept and slope Flynn effects for both maternal birthyear and first child birthyear, have implications for research aiming to explain the Flynn effect.

Why Are Old-Age Disabilities Decreasing in Sweden and Denmark? Evidence on the Contribution of Cognition, Education, and Sensory Functions

OBJECTIVES

Improvements in educational attainment, cognitive and sensory functions, and a decline in the prevalence of disabilities have been observed in older adults in Sweden and Denmark. In the present study, it was investigated whether better cognition, higher educational attainment, and improved sensory function among older adults aged 60 and older in these countries have contributed to decreasing rates of old-age disabilities.

METHODS

The analyses were based on repeated cross-sectional data from the Survey of Health, Ageing, and Retirement in Europe for the 2004-2017 period. Descriptive data were used to benchmark the declining prevalence of disabilities, improving cognitive and sensory functions, and increased educational level. The association between time and disabilities was analyzed with logistic regression models, and the contribution of the improved cognitive function, education, and sensory function to the declining prevalence of old-age disabilities was estimated using the Karlson-Holm-Breen method for mediation analysis.

RESULTS

The analysis suggests that the declining prevalence of old-age disabilities in Sweden and Denmark between 2004 and 2017 can largely be attributed to improved cognitive function and vision and to a lesser extent by education and hearing ability.

DISCUSSION

These findings raise important questions about the causal mechanisms producing the associations between cognition, education, and sensory functions and disability in older age. Future studies should explore the causal nature of the associations between these mediators and old-age disabilities. In addition, they should explore whether these findings differ across regional and cultural contexts and over different time periods.

Assessment of intelligence quotient in patients with neuromyelitis optica spectrum disease and multiple sclerosis

BACKGROUND

Cognitive impairment is common in people living with neuromyelitis optica spectrum disease (NMOSD) and multiple sclerosis (MS). However, there is little published data on intelligence quotient (IQ) in NMOSD patients. Therefore, we performed the present study to compare IQ scores across NMOSD, MS, and control groups.

METHOD

In this cross-sectional study, 49 NMOSD (30 with positive aquaporin4 antibody), 41 MS, and 20 control individuals were recruited. The IQ score for each person was measured using Wechsler Adult Intelligence Scale-Revised (WAIS-R). Participants were reported on eleven scores of subsets, verbal IQ (VIQ), performance IQ (PIQ), and full score IQ (FSIQ).

RESULT

The scores of FSIQ, VIQ, PIQ, vocabulary, similarities, and digit-symbol in NMOSD and MS individuals were lower than the control group. Relative to control, NMOSD patients reported a lower score of information. We found no difference between NMOSD and MS groups, except in vocabulary and similarities. No significant difference between seropositive and seronegative NMOSD groups was observed except for the information and block design. In NMOSD group, a greater EDSS score was associated with decreased scores of FSIQ, VIQ, and PIQ. Being employed and being married were associated with greater scores of VIQ and PIQ, respectively. In both NMOSD and MS groups, advanced education was associated with increased scores of FSIQ and VIQ.

CONCLUSION

Our study showed decreased IQ scores in NMOSD and MS. Further studies are required to examine intellectual quotient in people with NMOSD and MS.

Secular Trends in Head Size and Cerebral Volumes In the Framingham Heart Study for Birth Years 1902-1985

Background Recent data suggest that dementia incidence is declining. We investigated whether similar secular trends consisting of increasing size of brain structures and improving memory performance could be simultaneously occurring as a possible explanation. Method The Framingham Heart Study is a 3 generation, longitudinal study that includes cognitive assessment and medical surveillance. This study cohort consisted of 4,506 unique, non-demented, stroke free, individuals with brain MRI, cognitive assessment, and demographic information spanning dates of birth from 1902 to 1985. Outcomes consisted of height, MRI, and memory measures. Covariates included age at MRI, sex, decade of birth, and all interactions. Models with neuropsychological outcomes also included educational achievement as a covariate. Results Height and intracranial (TCV), hippocampus and cortical gray matter volumes were significantly larger, and memory performance significantly better, with advancing decades of birth after adjusting for age, sex, and interactions. Sensitivity analysis using progressively restricted age-ranges to reduce the association between age and decade of birth, confirmed the findings. Mediation analysis showed that hippocampal volume mediated approximately 5-7% of the effect of decade of birth on logical memory performance. Discussion These findings indicate improvement in brain health and memory performance with advancing decades of birth. Although brain structures are under substantial genetic influence, we conclude that improved early life environmental influences over ensuing decades likely explain these results. We hypothesize that these secular improvements are consistent with declining dementia incidence in this cohort potentially through a mechanism of increased brain reserve.

Students' intelligence test results after six and sixteen months of irregular schooling due to the COVID-19 pandemic

The COVID-19 pandemic has affected schooling worldwide. In many places, schools closed for weeks or months, only part of the student body could be educated at any one time, or students were taught online. Previous research discloses the relevance of schooling for the development of cognitive abilities. We therefore compared the intelligence test performance of 424 German secondary school students in Grades 7 to 9 (42% female) tested after the first six months of the COVID-19 pandemic (i.e., 2020 sample) to the results of two highly comparable student samples tested in 2002 (n = 1506) and 2012 (n = 197). The results revealed substantially and significantly lower intelligence test scores in the 2020 sample than in both the 2002 and 2012 samples. We retested the 2020 sample after another full school year of COVID-19-affected schooling in 2021. We found mean-level changes of typical magnitude, with no signs of catching up to previous cohorts or further declines in cognitive performance. Perceived stress during the pandemic did not affect changes in intelligence test results between the two measurements.

Today's Older Adults Are Cognitively Fitter Than Older Adults Were 20 Years Ago, but When and How They Decline Is No Different Than in the Past

History-graded increases in older adults' levels of cognitive performance are well documented, but little is known about historical shifts in within-person change: cognitive decline and onset of decline. We combined harmonized perceptual-motor speed data from independent samples recruited in 1990 and 2010 to obtain 2,008 age-matched longitudinal observations (M = 78 years, 50% women) from 228 participants in the Berlin Aging Study (BASE) and 583 participants in the Berlin Aging Study II (BASE-II). We used nonlinear growth models that orthogonalized within- and between-person age effects and controlled for retest effects. At age 78, the later-born BASE-II cohort substantially outperformed the earlier-born BASE cohort (d = 1.20; 25 years of age difference). Age trajectories, however, were parallel, and there was no evidence of cohort differences in the amount or rate of decline and the onset of decline. Cognitive functioning has shifted to higher levels, but cognitive decline in old age appears to proceed similarly as it did two decades ago.

Predicting normative data in healthy individuals on the computerized wisconsin card sorting test using regression models

BACKGROUND

Computerized neuropsychological tests provide advantages to clinicians with cost, administration, and time. However, studies have pointed out performance differences between manual and computerized versions of some neuropsychological tests. One of these is the Wisconsin Card Sorting Test (WCST). Due to the performance difference, the normative data of manual tests cannot be used for their computerized versions. Therefore, normative data searches are needed for computerized versions.

OBJECTIVE

This study aimed to determine the norm values of WCST-CV in a healthy sample.

METHODS

422 healthy adults aged 18-78 participated in this study. WCST-CVsub-scores are modeled by Regression Analysis based on Age and Education level to generate normative data. Among the 13 WCST scores, the regression models for WCST 2, WCST 3, WCST 4, WCST 10, and WCST 11 are significant. WCST 2, WCST 4, and WCST 11 scores are estimated with Ordinary Least Squares (OLS). However, WCST 3 and WCST 10 scores are estimated with Weighted Least Squares (WLS) due to the violation of the homoscedasticity assumption.

RESULTS

The regression results show that p-values calculated from error increase as age and education level increase.

CONCLUSION

As a result of our research, norm values between 18-78 years of age were produced using RA. It was determined that gender was not significant for any sub-score. Therefore, only age and education level from socio-demographic variables were included in the model.

Outcome at early school age and adolescence after hypothermia-treated hypoxic-ischaemic encephalopathy: an observational, population-based study

OBJECTIVE

We aimed to describe long-term outcomes following hypoxic-ischaemic encephalopathy (HIE) treated with therapeutic hypothermia (TH).

DESIGN

Prospective, population-based observational study.

SETTING

Tertiary level neonatal intensive care units and neonatal outpatient clinic, Karolinska University Hospital, Stockholm, Sweden.

PATIENTS

Sixty-six infants treated with TH due to HIE between 2007 and 2009.

INTERVENTIONS

At 6-8 years and 10-12 years of age, children were assessed using a standardised neurological examination, the Movement Assessment Battery for Children, Second Edition (MABC-2) and the Wechsler Intelligence Scales for Children IV/V. Parents completed the Five-to-Fifteen (FTF) questionnaire.

MAIN OUTCOME MEASURES

Adverse outcome among survivors was defined as cerebral palsy (CP), epilepsy, hearing or visual impairment, full-scale IQ (FSIQ) below 85, attention deficit disorder with/without hyperactivity, autism spectrum disorder or developmental coordination disorder.

RESULTS

Mortality was 12%. Seventeen per cent of survivors developed CP. Mean FSIQ was normal in children without major neuromotor impairment. Assessment in early adolescence revealed emerging deficits in 26% of children with a previously favourable outcome. The proportion of children exhibiting executive difficulties increased from 7% to 19%. This was reflected also by a significantly increased proportion of children with an FTF score >90th percentile compared with norms in early adolescence. The proportion of children with an MABC-2 score ≤5th percentile was also significantly increased compared with norms.

CONCLUSIONS

Survivors without major neuromotor impairment have normal intelligence. The incidence of executive difficulties appears to be increased in this patient population. More subtle difficulties may go undetected at early school-age.

Assessing the Attainment Rates of Updated CDC Milestones Using a New Israeli Developmental Scale

OBJECTIVES

Developmental milestones norms are widely used worldwide and are fundamental for early childhood developmental surveillance. We compared a new Israeli evidence-based national developmental scale with the recently updated Centers for Disease Control and Prevention (CDC) checklists.

METHODS

We used a cohort of nearly 4.5 million developmental assessments of 758 300 full-term born children aged 0 to 6 years (ALL-FT cohort), who visited maternal child health clinics in Israel for routine developmental surveillance. Among the assessed milestones of 4 developmental domains (gross motor, fine motor, language, and personal-social) we identified milestones that had equivalents on the CDC checklists and assessed the attainment rates of the Israeli children at the ages recommended by the CDC, at which ≥75% of the children would be expected to achieve the milestone. The analysis was repeated on a subgroup of 658 958 children who were considered healthy, typically developing by their birth and growth characteristics (NORMAL-FT cohort).

RESULTS

There were 29 milestones, across all developmental domains and assessment ages, whose definitions by both tools were compatible, and could be compared. The attainment rate at the CDC-recommended age was >90% for 22 (76%) and 23 (79%) milestones, and the median attainment rates were 95.2% and 96.3% in the ALL-FT and NORMAL-FT cohorts, respectively.

CONCLUSIONS

For almost all comparable milestones of all domains and all ages, children of the Israeli cohorts achieved the milestones earlier than expected by the CDC-defined threshold age. Evidence-based analysis of milestone norms among different populations may enable adjustments of developmental scales and facilitate more personalized developmental surveillance.

Neurodiversity and Intelligence: Evaluating the Flynn Effect in Children with Autism Spectrum Disorder

The Flynn Effect (FE) among child and adolescent populations indicates that intelligence scores improve by about three points per decade. Using nine years of data from the National Database for Autism Research, this study examined whether general intelligence changed significantly for nine cohorts with autism spectrum disorder (ASD; N = 671). Analyses demonstrated a downward trend such that Cohen's d from 1998 to 2006 was - 0.27. The mean IQ is 92.74 for years 1-3, 91.54 for years 4-6, and 87.34 for years 7-9, indicating a reverse FE of 5.4 points per decade. A linear regression revealed a significant negative FE comparable to the positive effect of age on IQ among those with ASD. Implications for research, practice, and law are discussed.

The Wisdom Researchers and the Elephant: An Integrative Model of Wise Behavior

This article proposes an integrative model of wise behavior in real life. While current research findings depend considerably on how wisdom is conceptualized and measured, there are strong conceptual commonalities across psychological wisdom models. The proposed model integrates the components of several existing models into a dynamic framework explaining wise behavior. The article first specifies which real-life situations require wisdom and discusses characteristics of wise behavior. The core proposition of the model is that in challenging real-life situations, noncognitive wisdom components (an exploratory orientation, concern for others, and emotion regulation) moderate the effect of cognitive components (knowledge, metacognitive capacities, and self-reflection) on wise behavior. The model can explain the situation specificity of wisdom and the commonalities and differences between personal and general wisdom. Empirically, it accounts for the considerable variation in correlations among wisdom measures and between wisdom measures and other variables. The model has implications for the design of wisdom-fostering interventions and new wisdom measures.

Secular Trends in Dementia Free Cognitive Function in Older Adults: A Systematic Review

BACKGROUND

Although numerous studies have reported a decrease in dementia risk in the last two decades, it is unclear whether dementia-free cognitive function is also changing across generations.

OBJECTIVE

The objective was to systematically evaluate the published data on generational differences in cognitive function in the older population.

METHODS

Searches were performed on PubMed, Embase, and PsychInfo for articles published in English before 20 June 2021. Included studies were from population-based samples that reported generational differences in cognition in individuals without dementia, aged ≥60 years.

RESULTS

28,101 studies were identified and 15 selected covering the period from 1971 to 2015: including studies from China, Europe, and the USA. The results show generally consistent findings of improvements or stability in dementia free cognitive function in later versus earlier born generations, but not for all cognitive domains. Prevalence of mild cognitive impairment and cognitive impairment no dementia has remained stable in the USA, UK, and China over the last two decades.

RESULTS

Prevalence of vascular related mild cognitive impairment has increased in China. Improvements in cognition may only partially be explained by increased educational attainment across generations.

CONCLUSION

This review provides evidence for generational effects in dementia-free cognitive function, predominately stability or improvements in performance, in later compared to earlier born individuals across different world regions. There is an urgent need to determine the factors driving such changes and whether they are being experienced in all world regions, particularly low- and middle-income countries where the burden of cognitive impairment is greatest and rising.

Comparison of the Wechsler Preschool and Primary Scale of Intelligence-Third Edition and the Leiter-R Intellectual Assessments for Clinic-Referred Children

A review of clinical records was conducted for children with developmental, emotional, and behavioral difficulties who were assessed with both the Wechsler preschool and primary scale of intelligence-third edition (WPPSI-III^CDN; Wechsler, 2004) and the Leiter international performance scale-revised (Leiter-R; Roid & Miller, 1997) within the same psychological evaluation. Forty children, ages 3–7, were included in this study. Pearson correlations showed that the IQ scores of the two instruments are strongly related (r > .70; p < .001). However, paired t-tests showed that overall Leiter-R scores (M = 99.03) were significantly higher than WPPSI-III^CDN scores (PIQ; M = 82.28, FSIQ; M = 75.24) (p < .001). The discrepancies between the instrument’s scores were clinically important as the use of only one of the two instruments could result in misclassification of child intellectual ability. These results should prompt professionals working with this clinical population to be cautious when using results from a single instrument in a child’s intellectual evaluation.

The role of school education in time-dependent changes of cognitive abilities in cohorts from midlife to old age

OBJECTIVES

It is examined whether older adults' cognitive ability in terms of delayed recall and verbal fluency is improving over time, whether this occurs over all educational levels and both sexes, and whether these changes are due to increasing proportions of individuals with higher education.

METHODS

Analyses are based on the German samples of the Survey on Health, Ageing and Retirement in Europe (waves 2004 and 2013).

RESULTS

Achievement levels increased over time and in all age groups. Improvements over educational levels occurred in parallel, differences between educational levels in the earlier survey were later reproduced at higher levels. Increasing proportions of individuals with higher education did not explain improvements of cognitive ability. No sex differences emerged.

CONCLUSION

Improved cognitive abilities could not be explained by upward shifts of educational levels. Improvements in higher age groups may foster improved health status and prolonged self-determined life in the older population.

Evolutionary Trajectories of Complex Traits in European Populations of Modern Humans

Humans have a great diversity in phenotypes, influenced by genetic, environmental, nutritional, cultural, and social factors. Understanding the historical trends of physiological traits can shed light on human physiology, as well as elucidate the factors that influence human diseases. Here we built genome-wide polygenic scores for heritable traits, including height, body mass index, lipoprotein concentrations, cardiovascular disease, and intelligence, using summary statistics of genome-wide association studies in Europeans. Subsequently, we applied these scores to the genomes of ancient European populations. Our results revealed that after the Neolithic, European populations experienced an increase in height and intelligence scores, decreased their skin pigmentation, while the risk for coronary artery disease increased through a genetic trajectory favoring low HDL concentrations. These results are a reflection of the continuous evolutionary processes in humans and highlight the impact that the Neolithic revolution had on our lifestyle and health.

A Half Century of Progress in US Student Achievement: Agency and Flynn Effects, Ethnic and SES Differences

Policymakers, conceptualized here as principals, disagree as to whether US student performance has changed over the past half century. To inform conversations, agents administered seven million psychometrically linked tests in math (m) and reading (rd) in 160 survey waves to national probability samples of cohorts born between 1954 and 2007. Estimated change in standard deviations (sd) per decade varies by agent (m: –0.10sd to 0.27sd, rd: –0.02sd to 0.12sd). Consistent with Flynn effects, median trends show larger gains in m (0.19sd) than in rd (0.04sd), though rates of progress for cohorts born since 1990 have increased in rd but slowed in m. Greater progress is shown by students tested at younger ages (m: 0.31sd, rd: 0.08sd) than when tested in middle years of schooling (m: 0.17sd, rd: 0.03sd) or toward the end of schooling (m: 0.06sd, rd: 0.02sd). Young white students progress more slowly (m: 0.28sd, rd: 0.09sd) than Asian (m: 46sd, rd: 0.28sd), black (m: 0.36sd, rd: 0.19sd), and Hispanic (m: 0.29sd, rd: 0.13sd) students. These ethnic differences generally attenuate as students age. Young students in the bottom quartile of the SES distribution show greater progress than those in the top quartile (difference in m: 0.08sd, in rd: 0.15sd), but the reverse is true for older students. Moderators likely include not only changes in families and schools but also improvements in nutrition, health care, and protection from contagious diseases and environmental risks. International data suggest that subject and age differentials may be due to moderators more general than just the United States.

Less-Intelligent and Unaware? Accuracy and Dunning–Kruger Effects for Self-Estimates of Different Aspects of Intelligence

People’s perceptions of their intelligence correlate only moderately with objective intelligence measures. On average, people overestimate themselves. According to the popular Dunning–Kruger effect, this is particularly true for low performers: across many domains, those in the lowest quartile overestimate their abilities the most. However, recent work using improved statistical approaches found little support for a Dunning–Kruger effect in general intelligence. We investigated accuracy and Dunning–Kruger effects for self-estimates of general, verbal, numerical, and spatial intelligence—domains that differed in how well they can be judged in the past. A total of 281 participants completed self-estimates and intelligence measures online. Self-estimates showed mostly moderate correlational accuracy that was slightly higher for numerical intelligence and lower for verbal intelligence. Across domains, participants rated their intelligence as above average. However, as their intelligence was indeed high, this was not an overestimation. While standard analyses indicated Dunning–Kruger effects in general, verbal, and spatial intelligence, improved statistical methods only yielded some support for one in verbal intelligence: people with lower verbal intelligence tended to have less self-knowledge about it. The generalizability of these findings is limited to young, highly educated populations. Nevertheless, our results contribute to a growing literature questioning the generality of the Dunning–Kruger effect.

Diversity of Intelligence is the Norm Within the Autism Spectrum: Full Scale Intelligence Scores Among Children with ASD

Although previous research helped to define differences in intelligence between neurotypicals and those with ASD, results were limited by small sample sizes or restricted subtests. Using data from the NIMH Data Archive, this study examined the intelligence of children with ASD (N = 671). Results demonstrate an average standard deviation of 25.75, which is 1.72 times greater than that of the normative sample for the WISC-III. Moreover, students with ASD are 12 times more likely than the general population of students to score within the intellectual disability range, but are also 1.5 times more likely to score in the superior range, suggesting that more students with ASD should be considered for giftedness. Determining the diversity of intelligence among those with ASD has implications for research, clinical practice, and neurological understanding.

Secular Improvements in Cognitive Aging: Contribution of Education, Health, and Routine Activities

Objectives

Limited evidence exists regarding the reasons for secular changes in cognitive functioning over historical time. Thus, we examined potential explanatory factors for changes in cognitive speed, a central dimension of cognitive functioning.

Methods

Population-based data of middle-aged and older adults from Germany (N = 5443) was used with baseline participants from 2002 to 2014, comparing the time periods 2002–2014.

Results

Cognitive speed improved in middle-aged adults (40–65) and older adults (66+). In both age groups, increases were partly explained by education, employment status, volunteering status, routine activities, and physical functioning. Changes in education were more important in explaining increases in older than in middle-aged adults, whereas changes in health were more important for explaining increases in middle-aged adults.

Conclusions

Cognitive speed increased in both age groups over historical time. Education, employment, volunteering, routine activities, and health were all important in explaining these changes, but their importance differed between age groups.

Neurodevelopmental Outcomes in Children With Inherited Liver Disease and Native Liver

OBJECTIVE

To evaluate neurodevelopmental status among children with inherited cholestatic liver diseases with native liver and variables predictive of impairment.

METHODS

Participants with Alagille syndrome (ALGS), progressive familial intrahepatic cholestasis (PFIC), and alpha 1 antitrypsin deficiency (A1AT) enrolled in a longitudinal, multicenter study and completed the Wechsler Preschool and Primary Scale of Intelligence-III or Intelligence Scale for Children-IV. Full Scale Intelligence Quotient (FSIQ) was analyzed continuously and categorically (>100, 85-99, 70-84, <70). Univariate linear regression was performed to study association between FSIQ and risk factors, stratified by disease.

RESULTS

Two hundred and fifteen completed testing (ALGS n = 70, PFIC n = 43, A1AT n = 102); median age was 7.6 years (3.0-16.9). Mean FSIQ in ALGS was lower than A1AT (94 vs 101, P = 0.01). Frequency of FSIQ < 85 (>1 standard deviation [SD] below average) was highest in ALGS (29%) versus 18.6% in PFIC and 12.8% in A1AT, and was greater than expected in ALGS based on normal distribution (29% vs 15.9%, P = 0.003). ALGS scored significantly lower than test norms in almost all Wechsler composites; A1AT scored lower on Working Memory and Processing Speed; PFIC was not different from test norms. Total bilirubin, alkaline phosphatase, albumin, hemoglobin, and parental education were significantly associated with FSIQ.

CONCLUSIONS

Patients with ALGS are at increased risk of lower FSIQ, whereas our data suggest A1AT and PFIC are not. A1AT and ALGS appear vulnerable to working memory and processing speed deficits suggestive of attention/executive function impairment. Malnutrition, liver disease severity, and sociodemographic factors appear related to FSIQ deficits, potentially identifying targets for early interventions.

Non-verbal cognitive development, learning, and symptoms of PTSD in 3- to 6-year-old refugee children

As IQ tests are commonly used as key assessment method, we address the question whether our commonly used standardized IQ tests are appropriate for children from families of diverse cultures and different educational levels in a refugee population. We examined 109 refugee children aged 3-7 years (M = 5.10 years, SD = 1.25) with the "Kaufman Assessment Battery for Children " (KABC-II; Kaufmann & Kaufmann, 2015) on a language-free scale (Scale of Intellectual Functioning, SIF) and learning performance (subtest Atlantis). With a non-verbal IQ of 81.5 (SD = 18.01), the population mean of the refugee children is more than one standard deviation lower than the mean of the German norm population. Standardized scores follow the normal distribution and are not correlated to any of the assessed markers of adversity (flight duration, time spent in Germany, child PTSD in parent rating, parental symptom load, and parental education level).Conclusion: The interpretation of IQ test results for refugee children should be done cautiously as results may underestimate their cognitive capacity. Environmental factors, such as high illiteracy among parents in this study, the lack of institutional education of children and high lifetime stress, may explain our findings.Trial registration: DRKS00021150. What is Known: • There is a high pervasiveness for the use of standardized IQ tests in the German health and education system to determine eligibility for special education and social services. What is New: • Refugee children score significantly lower than German children in a language-free IQ test. As results are normally distributed and not correlated to any of the assessed markers of adversity, the low scores in the refugee group might be due to missing formal education.

Secular trends in prevalent mild cognitive impairment: Data from the Swedish population‐based study Good Aging in Skåne

Background

Research suggests that incident dementia is decreasing, yet research on secular trends of prodromal dementia such as mild cognitive impairment (MCI) is lacking.

Methods

To determine change of MCI prevalence over time and potential explanatory factors, four baseline samples (years 2001–2020) of Swedish participants (n = 3910) aged 60 and 81 at examination were compared.

Results

An overall drop of 9 to 10 percentage points in MCI prevalence between 2001 and 2020 was observed, with lower odds ratios (OR) for MCI in the latest birth cohorts compared to earliest (e.g., ORs for 60‐year‐olds in latest born = 0.53; 95% confidence interval [CI] 0.37–0.76). Adjustments for sociodemographic (e.g., education), lifestyle, vascular and metabolic health and depression could not fully explain the observed MCI decline (e.g., 60‐year‐olds, OR = 0.59; 95% CI 0.40–0.88).

Discussion

Studies like this are imperative as even a slight postponement in the onset of dementia could have a substantial impact on future public health burden.

Genetically informed, multilevel analysis of the Flynn Effect across four decades and three WISC versions

This study investigated the systematic rise in cognitive ability scores over generations, known as the Flynn Effect, across middle childhood and early adolescence (7-15 years; 291 monozygotic pairs, 298 dizygotic pairs; 89% White). Leveraging the unique structure of the Louisville Twin Study (longitudinal data collected continuously from 1957 to 1999 using the Wechsler Intelligence Scale for Children [WISC], WISC-R, and WISC-III ed.), multilevel analyses revealed between-subjects Flynn Effects-as both decrease in mean scores upon test re-standardization and increase in mean scores across cohorts-as well as within-child Flynn Effects on cognitive growth across age. Overall gains equaled approximately three IQ points per decade. Novel genetically informed analyses suggested that individual sensitivity to the Flynn Effect was moderated by an interplay of genetic and environmental factors.

Anxiety severity and cognitive function in primary care patients with anxiety disorder: a cross-sectional study

BACKGROUND

Deficits in cognitive performance are reported in patients with anxiety disorders, but research is limited and inconsistent. We aimed to investigate cross-sectional associations between cognitive function, with focus on executive function, and anxiety severity in primary care patients diagnosed with anxiety disorders.

METHODS

189 Swedish patients aged 18-65 years (31% men) with anxiety disorders diagnosed according to Mini International Neuropsychiatric Interview were included. Severity of anxiety was assessed using Beck Anxiety Inventory self-assessment scale. Digit span, block design and matrix reasoning tests from the Wechsler Adult Intelligence Scale IV, and the design fluency test from the Delis-Kaplan Executive Function System were used. Multivariable linear regression models were applied to investigate the relationship of anxiety severity and cognitive functioning. Comparisons were also performed to a normed non-clinical population, using the Wilcoxon signed rank test.

RESULTS

More severe anxiety was associated with lower digit span test scores (R² = 0.109, B = -0.040, p = 0.018), but not with block design, matrix reasoning or design fluency tests scores, after adjustment for comorbid major depression in a multivariable model. When compared to a normed population, patients with anxiety performed significantly lower on the block design, digit span forward, digit span sequencing and matrix reasoning tests.

CONCLUSIONS

Severity of anxiety among patients with anxiety disorder was associated with executive functions related to working memory, independently of comorbid major depression, but not with lower fluid intelligence. A further understanding of the executive behavioral control in patients with anxiety could allow for more tailored treatment strategies including medication, therapy and interventions targeted to improve specific cognitive domains.

The secular trend of intelligence test scores: The Danish experience for young men born between 1940 and 2000

The present study investigated the Danish secular trend of intelligence test scores among young men born between 1940 and 2000, as well as the possible associations of birth cohort changes in family size, nutrition, education, and intelligence test score variability with the increasing secular trend. The study population included all men born from 1940 to 2000 who appeared before a draft board before 2020 (N = 1,556,770). At the mandatory draft board examination, the approximately 19-year-old men underwent a medical examination and an intelligence test. In the statistical analyses, the IQ mean and standard deviation (SD) were estimated separately for each of the included annual birth cohorts based on information from birth cohorts with available total intelligence test scores for all tested individuals (i.e. 1940-1958 and 1987-2000; the mean and SD were interpolated for the intermediate birth cohorts). Moreover, the possible associations with birth cohort changes in family size, height as a proxy for nutritional status, education, and IQ variability were investigated among those birth cohorts for whom a secular increase in intelligence test scores was found. The results showed that the estimated mean IQ score increased from a baseline set to 100 (SD: 15) among individuals born in 1940 to 108.9 (SD: 12.2) among individuals born in 1980, since when it has decreased. Focusing on the birth cohorts of 1940-1980, for whom a secular increase in intelligence test scores was found, birth cohort changes in family size, height, and education explained large proportions of the birth cohort variance in mean intelligence test scores, suggesting that these factors may be important contributors to the observed Flynn effect in Denmark.

Understanding Replication in a Way That Is True to Science

In this article, I critically examine a number of widely held beliefs about the nature of replication and its place in science, with particular reference to psychology. In doing so, I present a number of underappreciated understandings of the nature of science more generally. I contend that some contributors to the replication debates overstate the importance of replication in science and mischaracterize the relationship between direct and conceptual replication. I also claim that there has been a failure to appreciate sufficiently the variety of legitimate replication practices that scientists engage in. In this regard, I highlight the tendency to pay insufficient attention to methodological triangulation as an important strategy for justifying empirical claims. I argue, further, that the replication debates tend to overstate the closeness of the relationship between replication and theory construction. Some features of this relationship are spelt out with reference to the hypothetico-deductive and the abductive accounts of scientific method. Additionally, an evaluation of the status of replication in different characterizations of scientific progress is undertaken. I maintain that viewing replication as just one element of the wide array of scientific endeavors leads to the conclusion that it is not as prominent in science as is often claimed.