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Many studies have found that conservatives show an advantage in mental health and happiness and various causes of this have been debated (e.g., religiousness, ideology, or genetics). However, not much attention has been given to examining whether this advantage is psychometrically real, or whether it is due to test bias. We analyzed data from two large Finnish surveys of adults (Ns = 848 and 4,978) from Lahtinen (2024), that measured general anxiety and depression symptoms, as well as a new wokeness scale. Using differential item functioning tests, we found no evidence for measurement bias in these scales. The correlation between index scores of wokeness and mental health (internalizing) was −0.36, which increased to −0.41 when measurement error was removed. The association between wokeness and anxiety (r = −0.33, adjusted r = 0.37) was stronger than wokeness and depression (r = 0.20, adjusted r = 0.22). [ABSTRACT FROM AUTHOR]

Previous studies have found a high degree of assortative mating for educational attainment (r =.56). However, this can be confounded by cohort effects or country effects, where certain nations may have more pronounced assortative mating than others. In addition, method variance regarding how educational attainment is measured may also result in heterogeneity of effect sizes. Effect sizes were gathered from various datasets and from academic literature, resulting in a large collection of effect sizes (k = 1498, n = 9,159,098), spanning 84 different countries. Assortative mating for educational attainment was stronger than what previous literature suggested (r =.66, [.64,.68]), largely due to the fact that assortative mating for educational attainment is stronger when latent methods are used. The strongest predictors of assortative mating for education between countries were individualism (r = −.61, p <.001) and HDI (r = −.56, p <.001). Assortative mating over time was found to vary by region. Capitalist Europe experienced an increase in assortative mating for education, while Communist Europe experienced a decrease. The United States had a non-linear trend in assortative mating for educational attainment, as it decreased from 1875 to 1926, increased from 1926 to 1945, decreased from 1945 to 1958, increased from 1958 to 1977, and decreased from 1977 onwards. [ABSTRACT FROM AUTHOR]

This study examines the temporal and geographical evolution of polygenic scores (PGSs) across cognitive measures (Educational Attainment [EA], Intelligence Quotient [IQ]), Socioeconomic Status (SES), and psychiatric conditions (Autism Spectrum Disorder [ASD], schizophrenia [SCZ]) in various populations. Our findings indicate positive directional selection for EA, IQ, and SES traits over the past 12,000 years. Schizophrenia and autism, while similar, showed different temporal patterns, aligning with theories suggesting they are psychological opposites. We observed a decline in PGS for neuroticism and depression, likely due to their genetic correlations and pleiotropic effects on intelligence. Significant PGS shifts from the Upper Paleolithic to the Neolithic periods suggest lifestyle and cognitive demand changes, particularly during the Neolithic Revolution. The study supports a mild hypothesis of Gregory Clark's model, showing a noticeable rise in genetic propensities for intelligence, academic achievement and professional status across Europe from the Middle Ages to the present. While latitude strongly influenced height, its impact on schizophrenia and autism was smaller and varied. Contrary to the cold winters theory, the study found no significant correlation between latitude and intelligence. [ABSTRACT FROM AUTHOR]

This article evaluates the relationship between inequality in cognitive test scores across countries and income inequality. By meta-analyzing the standard deviations in PISA results from 2000 to 2018, the authors construct a measure of intelligence inequalities across countries. They then test this measure to investigate if it has any association with income inequality as measured by the gini index. Across all models and subsamples, the authors do not find a positive association between intelligence inequality and income inequality. In models where the coefficient is statistically significant, the direction is unexpectedly negative, implying greater intelligence inequality is associated with lower income inequality. This is contrary to theoretical predictions of a positive association between these variables. Finally, the authors also find some evidence that greater mean intelligence is associated with lower levels of income inequality. [ABSTRACT FROM AUTHOR]

Previous studies have found that the ability of a country's cognitive elite is generally more predictive than the average ability. However, these studies have relied on sub-optimal methods. Here, the authors tested smart fraction theory, as it is known, using a pre-residualization approach, which obviates the problem of collinearity. For outcome variables, they utilised the 51 indicators of the Social Progress Index, as well as 6 economic variables. Like in previous research, the authors operationalized the ability of the intellectual class as the 95th percentile score. Consistent with smart fraction theory, they found evidence that the ability of the intellectual class does influence outcomes over and above that of the average ability. For the 93 countries with available data, average ability explained 57% of the variation in country performance. Adding the 95th percentile score increased this to 66%. The authors discuss their findings in light of the existing literature. [ABSTRACT FROM AUTHOR]

A recent study by Dutton et al. (J Relig Health 59:1567–1579. https://doi.org/10.1007/s10943-019-00926-3, 2020) found that the religiousness-IQ nexus is not on g when comparing different groups with various degrees of religiosity and the non-religious. It suggested, accordingly, that the nexus related to the relationship between specialized analytic abilities on the IQ test and autism traits, with the latter predicting atheism. The study was limited by the fact that it was on group-level data, it used only one measure of religiosity that measure may have been confounded by the social element to church membership and it involved relatively few items via which a Jensen effect could be calculated. Here, we test whether the religiousness-IQ nexus is on g with individual-level data using archival data from the Vietnam Experience Study, in which 4462 US veterans were subjected to detailed psychological tests. We used multiple measures of religiosity—which we factor-analysed to a religion-factor—and a large number of items. We found, contrary to the findings of Dutton et al. (2020), that the IQ differences with regard to whether or not subjects believed in God are indeed a Jensen effect. We also uncovered a number of anomalies, which we explore. [ABSTRACT FROM AUTHOR]

Chronotype and cognitive ability are two human phenotypes with an uneven geographic distribution due to both selective migration and causal environmental effects. In our study, we aimed to examine the relationship between geographic variables, cognitive ability and chronotype. We used a large anonymized sample (n = 25,700, mostly from the USA, UK, Canada and Australia) of dating site users to estimate chronotype and cognitive ability from questionnaire responses using item response theory. We matched each user to geographic coordinates and city size using the reported locations and geographic databases. In line with previous research we found that male sex, younger age, residence in a more populous locale, higher cognitive ability and more westward position within the same time zone were associated with later chronotype. Male sex, younger age, residence in a more populous locale, later chronotype and higher latitude were associated with higher cognitive ability, but the effect of population on chronotype and latitude on cognitive ability was only present in the USA. The relationship between age and chronotype was stronger in males, and the relationship between chronotype and cognitive ability was stronger in males and in older participants. Population density had an independent association with cognitive ability, but not chronotype. Our results confirm the uneven geographic distribution of chronotype and cognitive ability. These findings generalize across countries, but they are moderated by age and sex, suggesting both biological and cultural effects. [ABSTRACT FROM AUTHOR]

Via meta-analysis, we examined whether the heritability of intelligence varies across racial or ethnic groups. Specifically, we tested a hypothesis predicting an interaction whereby those racial and ethnic groups living in relatively disadvantaged environments display lower heritability and higher environmentality. The reasoning behind this prediction is that people (or groups of people) raised in poor environments may not be able to realize their full genetic potentials. Our sample (k = 16) comprised 84,897 Whites, 37,160 Blacks, and 17,678 Hispanics residing in the United States. We found that White, Black, and Hispanic heritabilities were consistently moderate to high, and that these heritabilities did not differ across groups. At least in the United States, Race/Ethnicity × Heritability interactions likely do not exist. • We meta-analyze whether race or ethnicity moderate the heritability of intelligence. • The main sample (k = 16) was comprised of Whites Blacks, and Hispanics from the USA. • We found moderate to high heritabilities for both groups. • Heritabilities, however, did not substantially differ by race or ethnicity. • Results are largely inconsistent with predictions from the Scarr-Rowe hypothesis. [ABSTRACT FROM AUTHOR]

Using a sample of ~3,100 U.S. counties, we tested geoclimatic explanations for why cognitive ability varies across geography. These models posit that geoclimatic factors will strongly predict cognitive ability across geography, even when a variety of common controls appear in the regression equations. Our results generally do not support UV radiation (UVR) based or other geoclimatic models. Specifically, although UVR alone predicted cognitive ability at the U.S. county-level (β = -.33), its validity was markedly reduced in the presence of climatic and demographic covariates (β = -.16), and was reduced even further with a spatial lag (β = -.10). For climate models, average temperature remained a significant predictor in the regression equation containing a spatial lag (β = .35). However, the effect was in the wrong direction relative to typical cold weather hypotheses. Moreover, when we ran the analyses separately by race/ethnicity, no consistent pattern appeared in the models containing the spatial lag. Analyses of gap sizes across counties were also generally inconsistent with predictions from the UVR model. Instead, results seemed to provide support for compositional models. [ABSTRACT FROM AUTHOR]

Abstract Mean scores on English-based graduate admissions exams vary strongly country by country. Here we test four hypotheses for this variance. The first is that samples of would-be graduate students are not representative of the countries from which they came. Second, English Language familiarity might account for cross-national variance on these exams. Third, national differences in well-being explain national differences in exam scores. Finally, variance in national IQ (NIQ) captures most of the variance in scores on admissions exams. We thus coded two extant measures of NIQ, and national scores on the following three admissions exams: The Graduate Management Admission Test (GMAT; n = 200 countries), Graduate Record Exam (GRE; n = 149), and Test of English as a Foreign Language (TOEFL; n = 175). Partial support was found for both the unrepresentative samples and language familiarity hypotheses. The well-being hypothesis was not supported because despite large correlations between it and exam scores, these effects were wiped out when NIQ also appeared in the regression equations. The NIQ hypothesis received the most support in that it strongly predicted admissions exam total scores (GMAT, r = 0.68 (N = 161); GRE, r = 0.71 (N = 141); TOEFL, r = 0.61 (N = 153). Moreover, these relationships (excluding those with the TOEFL) were robust to the controls of English familiarity and well-being. We end by discussing how our data also validate the existence of Rindermann's (2007) "Big G" nexus. Highlights • We examined associations between National IQ and graduate admissions exam scores. • GRE, GMAT, and TOEFL exam scores correlated strongly with National IQ. • Associations mostly persisted when controlling English familiarity and well-being. • National IQ explained most of the variance in graduate admissions exam scores. [ABSTRACT FROM AUTHOR]

Differences in intelligence have previously been found to be related to a wide range of inter-individual and international social outcomes. There is evidence indicating that intelligence differences are also related to different regional outcomes within nations. A quantitative and narrative review is provided for twenty-two countries (number of regions in parentheses): Argentina (24 to 437), Brazil (27 to 31), British Isles (12 to 392), Chile (15), China (31), Colombia (33), Denmark (7), Finland (4), France (90), Germany (16), India (33), Italy (12 to 19), Japan (47), Mexico (31 to 32), Peru (1468), Portugal (5), Russia (29 to 79), Spain (15 to 48), Switzerland (47), Turkey (12), the USA (30 to 3100), and Vietnam (61). Between regions, intelligence is significantly associated with a wide range of economic, social, and demographic phenomena, including income ( r unweighted  =  .56), educational attainment ( r unweighted  =  .59), health ( r unweighted  =  .49), general socioeconomic status ( r unweighted  =  .55), and negatively with fertility ( r unweighted  = −.51) and crime ( r unweighted  = −.20). Proposed causal models for these differences are noted. It is concluded that regional differences in intelligence within nations warrant further focus; methodological concerns that need to be addressed in future research are detailed. [ABSTRACT FROM AUTHOR]

An article's keywords are distinct because they represent what authors feel are the most important words in their papers. Combined, they can even shed light on which research topics in a field are popular (or less so). Here we conducted bibliometric keyword analyses of articles published in the journal, Intelligence (2000–2016). The article set comprised 916 keyword-containing papers. First, we analyzed frequencies to determine which keywords were most/least popular. Second, we analyzed Web of Science (WOS) citation counts for the articles listing each keyword and we ran regression analyses to examine the effect of keyword categories on citation counts. Third, we looked at how citation counts varied across time. For the frequency analysis, "g factor", "psychometrics/statistics", and "education" emerged as the keywords with the highest counts. Conversely, the WOS citation analysis showed that papers with the keywords "spatial ability", "factor analysis", and "executive function" had the highest mean citation values. We offer tentative explanations for the discrepant results across frequencies and citations. The analysis across time revealed several keywords that increased (or decreased) in frequency over 17 years. We end by discussing how bibliometric keyword analysis can detect research trends in the field, both now and in the past. [ABSTRACT FROM AUTHOR]

Here we reply to Giangrande and Turkheimer's (2022; G&T) recent critique of a meta-analysis we published in Intelligence regarding the Scarr-Rowe Hypothesis and the apparent lack of putative race/ethnic group differences in the heritability of intelligence (Pesta et al., 2020). Our rebuttal is divided into three sections that address ubiquitous misstatements in their critique: Section 1 focuses on conceptual and theoretical points. Section 2 addresses methodological, statistical, and interpretative points. Section 3 provides new analyses suggested by G&T that support our original interpretations. We note that G&T published their critique in Perspectives on Psychological Science (PoPS), which did not invite us to respond before their paper was published and our subsequent submission of a rebuttal was not accepted. Our unsuccessful appeal of these events based on possible ethics violations is detailed here (Appendix E). We recognize that this is a controversial area of research with legitimate disagreements and hope our responses maintain a degree of rigor and professionalism that others can emulate. • We provide our rebuttal of Giangrande and Turkheimer (2022). • We document numerous errors and false claims in their review. • We provide the timeline of events leading to our submission here. [ABSTRACT FROM AUTHOR]