Evidence for the Scarr-Rowe Effect on Genetic Expressivity in the Health and Retirement Study.

The Scarr-Rowe effect is a gene × environment interaction, which is characterized by a negative association between exposure to low socioeconomic status (SES) environments and the additive heritability of cognitive ability. Utilizing a polygenic score for educational attainment (EA3), it was found that the two-way interaction between EA3 and parental educational attainment (EA; used as a proxy for parental SES) was a significant positive predictor of participants' composite cognitive ability (IQ) score (ß = .018, SE = .008, p = .028) after controlling hierarchically for the direct effects of (population-stratification-controlled) EA3, parental EA, and 20 distinct interaction terms (10 involving the interactions between the principal components [PCs] and EA3, and 10 involving the interaction between the PCs and parental EA). The presence of this interaction is consistent with the Scarr-Rowe effect, as the expressivity of EA3 on cognitive ability increases with increasing parental EA. No statistically significant sex differences in the effect magnitudes were found, although the effect was significantly present in the female but not male sample.

Paternal Age is Negatively Associated with Religious Behavior in a Post-60s But Not a Pre-60s US Birth Cohort: Testing a Prediction from the Social Epistasis Amplification Model.

Participation in social behaviors that enhance group-level fitness may be influenced by mutations that affect patterns of social epistasis in human populations. Mutations that cause individuals to not participate in these behaviors may weaken the ability of members of a group to coordinate and regulate behavior, which may in turn negatively affect fitness. To investigate the possibility that de novo mutations degrade these adaptive social behaviors, we examine the effect of paternal age (as a well-established proxy for de novo mutation load) on one such social behavior, namely religious observance, since religiosity may be a group-level cultural adaptation facilitating enhanced social coordination. Using two large samples (Wisconsin Longitudinal Study and AddHealth), each of a different US birth cohort, paternal age was used to hierarchically predict respondent's level of church attendance after controlling for multiple covariates. The effect is absent in WLS (ß = .007, ns, N = 4560); however, it is present in AddHealth (ß = - .046, p < .05, N = 4873) increasing the adjusted model R2 by .005. The WLS respondents were (mostly) born in the 1930s, whereas the AddHealth respondents were (mostly) born in the 1970s. This may indicate that social-epistatic regulation of behavior has weakened historically in the USA, which might stem from and enhance the ability for de novo mutations to influence behavior among more recently born cohorts-paralleling the secular rise in the heritability of age at sexual debut after the sexual revolution.

How Intelligence Affects Fertility 30 Years On: Retherford and Sewell Revisited - With Polygenic Scores and Numbers of Grandchildren.

Using newly available polygenic scores for educational attainment and cognitive ability, this paper investigates the possible presence and causes of a negative association between IQ and fertility in the Wisconsin Longitudinal Study sample, an issue that Retherford and Sewell first addressed 30 years ago. The effect of the polygenic score on the sample's reproductive characteristics was indirect: a latent cognitive ability measure, comprised of both educational attainment and IQ, wholly mediated the relationship. Age at first birth mediated the negative effect of cognitive ability on sample fertility, which had a direct (positive) effect on the number of grandchildren. Significantly greater impacts of cognitive ability on the sample's fertility characteristics were found among the female subsample. This indicates that, in this sample, having a genetic disposition toward higher cognitive ability does not directly reduce number of offspring; instead, higher cognitive ability is a risk factor for prolonging reproductive debut, which, especially for women, reduces the fertility window and, thus, the number of children and grandchildren that can be produced. By estimating the effect of the sample's reproductive characteristics on the strength of polygenic selection, it was found that the genetic variance component of IQ should be declining at a rate between -.208 (95% CI [-.020, -.383]) and -.424 (95% CI [-.041, -.766]) points per decade, depending on whether GCTA-GREML or classical behavior genetic estimates of IQ heritability are used to correct for 'missing' heritability.

MATERNAL SENSITIVITY AND PERFORMANCE AND VERBAL INTELLIGENCE IN LATE CHILDHOOD AND ADOLESCENCE.

The aim of this study was to investigate the association between maternal sensitivity and offspring intelligence in late childhood and adolescence. Secondary data (N=117) from the Block and Block (2006a, b) 30-year longitudinal study of Californian children, which began in the late 1960s, was used to test the hypothesis that maternal sensitivity in childhood would be predictive of late childhood and adolescent intelligence. Correlational analyses revealed that maternal sensitivity, as judged by raters viewing mother's interactions with their children in a set of four joint structured cognitive tasks when the child was 5 years of age, was associated with verbal and performance IQ test scores when the children were ages 11 and 18. Using hierarchical regression to control for child sex, socioeconomic status, child temperament, child baseline IQ (as measured at age 4), mother's level of education and mother's emotional nurturance, it was found that the maternal sensitivity and child and adolescent IQ association held for verbal, but not performance IQ. Furthermore, a pattern emerged in which the association between maternal sensitivity and verbal IQ was stronger for adolescents with a lower baseline IQ. The results suggest that maternal sensitivity is associated with offspring verbal intelligence and that this association holds when numerous variables are accounted for. Additionally, this association may be stronger for children with lower IQs.

Slowing life history (K) can account for increasing micro-innovation rates and GDP growth, but not macro-innovation rates, which declined following the end of the Industrial Revolution.

Baumard proposes that life history slowing in populations over time is the principal driver of innovation rates. We show that this is only true of micro-innovation rates, which reflect cognitive and economic specialization as an adaptation to high population density, and not macro-innovation rates, which relate more to a population's level of general intelligence.

Evidence for the Scarr-Rowe Effect on Genetic Expressivity in a Large U.S. Sample.

Using the continuous parameter estimation model (CPEM), a large genotyped adult sample of the population of Wisconsin, USA (the Wisconsin Longitudinal Study) is examined for evidence of the Scarr-Rowe effect, a gene × environment (G×E) interaction that reduces the heritability of IQ among those with low socioeconomic status (SES). This method allows the differential expressivity of polygenic scores predictive of both educational attainment and IQ (EA3) on the phenotype of IQ to be directly operationalized throughout the full range of these variables. Utilizing a parental SES factor-weighted composite as a measure of childhood SES, evidence for the Scarr-Rowe effect was found, that is, the genetic expressivity of EA3 on IQ increased with increasing parental SES (ß = 0.08, p = 4.71×10-10, df = 6,255). The effect was found for both the male and female samples separately, ß(males) = 0.08, p = 5.27×10-5, df = 3,018; ß(females) = 0.08, p = 1.93×10-6, df = 3,236. The effects were furthermore robust to removing outlying values of parental SES and to log-transforming the SES variable. The results are similar to those produced using a more conventional two-way interaction model, with IQ predicting the EA3 × log of parental SES interaction after the main effects; however, CPEM allows for greater model degrees of freedom, thus is better powered to detect the effect when it is small in magnitude (CPEM ß = 0.05, p = 6.69×10-5 vs. two-way interaction ß = 0.02, pone-tailed = .045, in both models log parental SES is used).

How Universal Is the General Factor of Personality? An Analysis of the Big Five in Forager Farmers of the Bolivian Amazon.

In various personality models, such as the Big Five, a consistent higher order general factor of personality (GFP) can be identified. One view in the literature is that the GFP reflects general social effectiveness. Most GFP studies, however, have been conducted in Western, educated, industrialized, and rich democracies (WEIRD). Therefore, to address the question of the universality of the GFP, we test whether the GFP can also be identified in a preliterate indigenous sample of Tsimane by using self-reports, spouse reports, and interviewer ratings. In the Tsimane, a viable GFP could be identified and the intercorrelations between personality traits were significantly stronger than in samples from industrial countries. The GFP correlated with the ratings of social engagement. In addition, self and spouse ratings of the GFP overlapped. Overall, the findings are in line with the notion that the GFP is a human universal and a substantive personality factor reflecting social effectiveness.

Larregue's Critique of Cofnas et al. (2017): A Rejoinder.

Data from the General Social Survey indicate that conservatives' self-reported trust in scientists has steadily decreased since 1974. In Cofnas et al. (The American Sociologist, 2017), we suggested that this trend may have been partly driven by the increasing tendency of scientific institutions, and the representatives of such institutions, to distort social science for the sake of liberal activism. Larregue (The American Sociologist, 2017) makes three opposing arguments: (1) It is "very hard" to establish the charge of bias, especially since we did "not state what [we] mean by 'bias.'" (2) We did not establish a causal relationship between scientists' (alleged) liberal activism and conservatives' distrust of science, and we ignored activism by conservative scientists. (3) We were wrong to advocate "affirmative action" for conservatives in academia. We address these arguments in turn: (1) Larregue does not engage with our main arguments that liberal bias exists in social science. (2) In recent years, prominent scientific organizations have, with great publicity, intervened in policy debates, always supporting the liberal side without exception. It is not unreasonable to assume that this would diminish conservatives' trust in these organizations. Contra Larregue, in Cofnas et al. (The American Sociologist, 2017) we explicitly acknowledged that conservative scientists can also be biased. (3) We never advocated "affirmative action" for conservatives, and in fact we object to such a proposal.

General intelligence is a source of individual differences between species: Solving an anomaly.

Burkart et al. present a paradox - general factors of intelligence exist among individual differences (g) in performance in several species, and also at the aggregate level (G); however, there is ambiguous evidence for the existence of g when analyzing data using a mixed approach, that is, when comparing individuals of different species using the same cognitive ability battery. Here, we present an empirical solution to this paradox.

How Cognitive Genetic Factors Influence Fertility Outcomes: A Mediational SEM Analysis.

Utilizing a newly released cognitive Polygenic Score (PGS) from Wave IV of Add Health (n = 1,886), structural equation models (SEMs) examining the relationship between PGS and fertility (which is approximately 50% complete in the present sample), employing measures of verbal IQ and educational attainment as potential mediators, were estimated. The results of indirect pathway models revealed that verbal IQ mediates the positive relationship between PGS and educational attainment, and educational attainment in turn mediates the negative relationship between verbal IQ and a latent fertility measure. The direct path from PGS to fertility was non-significant. The model was robust to controlling for age, sex, and race; furthermore, the results of a multigroup SEM revealed no significant differences in the estimated path coeficients across sex. These results indicate that those predisposed towards higher verbal IQ by virtue of higher PGS values are also predisposed towards trading fertility against time spent in education, which contributes to those with higher PGS values producing fewer offspring at this stage in their life course.

The more g-loaded, the more heritable, evolvable, and phenotypically variable: Homology with humans in chimpanzee cognitive abilities.

Expanding on a recent study that identified a heritable general intelligence factor (g) among individual chimpanzees from a battery of cognitive tasks, we hypothesized that the cognitive abilities that are more g-loaded would be more heritable and would present more additive genetic variance, in addition to showing more phenotypic variability. This pattern was confirmed, and is comparable to that found in humans, indicating fundamental homology. Finally, tool use presented the highest heritability, the largest amount of additive genetic variance and of phenotypic variance, consistent with previous findings indicating that it is associated with high interspecies variance and evolutionary rates in comparative primate studies.

Convergence between G and g in three monkey species (Sapajus spp, Ateles geoffroyi, and Macaca fascicularis).

An open question in comparative psychology is whether the source of correlations among different measures of ability (the g factor) is shared between species, or is distinct. This is examined using data on the performance of three monkey species (tufted capuchins, black-handed spider monkeys, and long-tailed macaques) on 16 cognitive ability measures. The differences between species pairs across measures are not generally strongly related to the degree to which the g factor loads on each subtest. Iteratively removing the subtests with the lowest coefficients of variance (CV), and recorrelating the species differences with subtest g-loadings was found to increase the association between the two. Across iterations, subtest pooled CV strongly and positively predicts the increase in the degree to which g-loadings are predictive of species difference in two comparisons, but is a weaker predictor in the comparison between tufted capuchins and black-handed spider monkeys. These associations were not related to phylogenetic distance but were very strongly related to species differences in the means of certain ecological factors. g-scores computed for each species on the basis of the three subtests with the highest CV values exhibited very-high magnitude (>.9) associations with species-level G-scores. G is simply the species-level equivalent of g, resulting from covariation among cognitive ability measures at the level of species differences. Finally, as with previous studies, subtests that show the greatest species differences seem to draw on executive functioning, and attention, suggesting that these may be a phylogenetically conserved source of g across many animal taxa. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Parent-offspring resemblance for educational attainment reduces with increased social class in a global sample: evidence for the compensatory advantage hypothesis.

Introduction: The degree to which (self-reported) social class predicts parent-offspring resemblance for educational attainment (EA) is examined in a globally representative dataset of 69,116 individuals sourced from 56 countries. Methods: A hierarchical general linear model is used to predict participant EA with the two-way interaction between class and parental EA, after controlling for regional effects, the main effects of age, class, parental EA, and interactions among these. Results: Social class-by-parental EA interaction negatively predicts participant EA (semipartial r = -0.04, 95% CI = -0.05 to -0.03), meaning that among those who report belonging to a "higher" social class, the degree of parent-offspring resemblance for EA is reduced, contrary to the Scarr-Rowe hypothesis, which holds that genetic influences on cognitive ability and related phenotypes (captured here in part by parent-offspring resemblance) should be greater among those from higher socioeconomic status (SES) backgrounds. These results replicate using a quantile regression model, where it was found that among those with lower social class ordinals, the strength of the parent-participant EA association is significantly stronger relative to those in the highest ordinal. No significant sex differences are present. Discussion: These findings are consistent with the compensatory advantage hypothesis, which predicts decreased heritability of EA and related phenotypes among affluent families, as increased access to educational resources should enhance opportunities for cognitive growth in a way that compensates for intrinsic disadvantages.

Genetics of psychic ability - A pilot case-control exome sequencing study.

INTRODUCTION: It is commonly believed that psychic ability, like many mental and physical traits, runs in families. This suggests the presence of a genetic component. If such a component were found, it would constitute a biological marker of psychic ability and inform environmental or pharmacologic means of enhancing or suppressing this ability. METHODS: A case-control study design was used to evaluate differences between psychic cases and non-psychic controls. Over 3,000 candidates globally were screened through two online surveys to locate people who claimed they and other family members were psychic. Measures of relevance to the claimed abilities (e.g., absorption, empathy, schizotypy) were collected and based on those responses, individuals with indications of psychotic or delusional tendencies were excluded from further consideration. Eligible candidates were then interviewed and completed additional screening tests. Thirteen individuals were selected as the final "psychic cases," and ten age-, sex-, and ethnicity-matched individuals with no claims of psychic ability were selected as controls. DNA from the saliva of these 23 participants was subjected to whole-exome sequencing. Two independent bioinformatics analyses were blindly applied to the sequenced data, one focusing exclusively on protein-coding sequences and another that also included some adjacent noncoding sequences. RESULTS: Sequencing data were obtained for all samples, except for one in the control group that did not pass the quality controls and was not included in further analyses. After unblinding the datasets, none of the protein-coding sequences (i.e., exons) showed any variation that discriminated between cases and controls. However, a difference was observed in the intron (i.e., non-protein-coding region) adjacent to an exon in the TNRC18 gene (Trinucleotide Repeat-Containing Gene 18 Protein) on chromosome 7. This variation, an alteration of GG to GA, was found in 7 of 9 controls and was absent from all psychic cases. DISCUSSION: The most conservative interpretation of these results is that they result from random population sampling. However, when the results are considered in relation to other lines of evidence, the results are more provocative. Further research is justified to replicate and extend these findings.

Anomalous information reception by mediums: A meta-analysis of the scientific evidence.

Background and purpose Mediumship is the ostensible phenomenon of human-mediated communication between deceased and living persons. In this paper, we perform a meta-analysis of all available modern experimental evidence, specifically from 2001 to December 2019, investigating the accuracy of apparently anomalously received information provided by mediums about deceased individuals. Methods 14 papers passed our selection criteria, for a total of 18 experiments. Both Bayesian and frequentist random effects models were used to estimate the aggregate effect size across studies. Results The overall standardized effect size (proportion index), estimated with a frequentist and a Bayesian random effects model, yielded a value of .18 (95% C.I. = .12 - .25) above the chance level. Furthermore, these estimates passed the control of two publication bias tests. Conclusions The results of this meta-analysis support the hypothesis that some mediums can retrieve information about deceased persons through unknown means.

A Meta-Analysis of the "Erasing Race" Effect in the United States and Some Theoretical Considerations.

The "erasing race" effect is the reduction of the salience of "race" as an alliance cue when recalling coalition membership, once more accurate information about coalition structure is presented. We conducted a random-effects model meta-analysis of this effect using five United States studies (containing nine independent effect sizes). The effect was found (ρ = 0.137, K = 9, 95% CI = 0.085 to 0.188). However, no decline effect or moderation effects were found (a "decline effect" in this context would be a decrease in the effect size over time). Furthermore, we found little evidence of publication bias. Synthetically correcting the effect size for bias stemming from the use of an older method for calculating error base rates reduced the magnitude of the effect, but the it remained significant. Taken together, these findings indicate that the "erasing race" effect generalizes quite well across experimental contexts and would, therefore, appear to be quite robust. We reinterpret the theoretical basis for these effects in line with Brunswikian evolutionary-developmental theory and present a series of predictions to guide future research in this area.

Circadian leaf movements facilitate overtopping of neighbors.

Many plants exhibit circadian clock-driven leaf movements whereby the leaves are raised during the day to achieve a relatively high angle during the evening, before lowering late in the night. Such leaf movements were first recorded over 2000 years ago but there is still much debate as to their purpose. We investigated whether such leaf movements within Arabidopsis, a ruderal rosette plant, can aid in overtopping leaves of neighboring plants. Wild type and circadian clock mutant plants were grown in an alternating grid system so that their leaves would meet as the plants grew. Experiments were performed using day lengths that matched the endogenous rhythm of either wild type or mutant. Plants grown in a day length shorter than their endogenous rhythm were consistently overtopped by plants which were in synchrony with the day night cycle, demonstrating a clear overtopping advantage resulting from circadian leaf movement rhythms. Furthermore, we found that this leaf overtopping as a result of correctly synchronized circadian leaf movements is additive to leaf overtopping due to shade avoidance. Curiously, this did not apply to plants grown in a day length longer than their endogenous period. Plants grown in a day length longer than their endogenous period were able to adapt their leaf rhythms and suffered no overtopping disadvantage. Crucially, our results show that, in a context-dependent manner, circadian clock-driven leaf movements in resonance with the external light/dark cycle can facilitate overtopping of the leaves of neighboring plants.

Sinistrality is associated with (slightly) lower general intelligence: A data synthesis and consideration of the secular trend in handedness.

The relationship between the general factor of intelligence (g) and handedness is investigated using a combined sample of 23511 respondents from three large databases: the NLSY'79 (US), NLSY'97 (US) and NCDS (UK). Dextrals - those who use their right hands were found to be 1.22 IQ points higher than sinistrals (left handers) after controlling for sex and age and correcting for sources of measurement error. To see if the association between IQ and handedness was strongest on the abilities that were the best measures of g, the method of correlated vectors was used to test for moderation. Across the three studies, g was found to very weakly negatively moderate the association between ability measure and handedness (ρ = -.023, K = 3, N = 23511), however in the NLSY'79, the coding speed subtest was an outlier in terms of the strength of its association with handedness. Its removal yielded indications of positive moderation in this dataset, which when aggregated boosted the overall vector correlation value to .539 (K = 3, N = 23511), suggesting that g might be an important moderator of this relationship. Secondary analysis of secular trend data on the changing percentage of sinistrals in Western populations indicates that overall, sinistrality has increased, entailing a g decline of .106 points over 150 years (.006 points per decade). The secular increase in sinistrality is consistent with other data indicating long-term declines in developmental stability and may stem from some combination of increasing mutation load and environmental stress in Western populations.

Secular Slowing of Auditory Simple Reaction Time in Sweden (1959-1985).

There are indications that simple reaction time might have slowed in Western populations, based on both cohort- and multi-study comparisons. A possible limitation of the latter method in particular is measurement error stemming from methods variance, which results from the fact that instruments and experimental conditions change over time and between studies. We therefore set out to measure the simple auditory reaction time (SRT) of 7,081 individuals (2,997 males and 4,084 females) born in Sweden 1959-1985 (subjects were aged between 27 and 54 years at time of measurement). Depending on age cut-offs and adjustment for aging related slowing of SRT, the data indicate that SRT has increased by between 3 and 16 ms in the 27 birth years covered in the present sample. This slowing is unlikely to be explained by attrition, which was evaluated by comparing the general intelligence × birth-year interactions and standard deviations for both male participants and dropouts, utilizing military conscript cognitive ability data. The present result is consistent with previous studies employing alternative methods, and may indicate the operation of several synergistic factors, such as recent micro-evolutionary trends favoring lower g in Sweden and the effects of industrially produced neurotoxic substances on peripheral nerve conduction velocity.