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On average men are taller and more muscular than women, which confers on them advantages related to female choice and during physical competition with other men. Sexual size dimorphisms such as these come with vulnerabilities due to higher maintenance and developmental costs for the sex with the larger trait. These costs are in keeping with evolutionary theory that posits large, elaborate, sexually selected traits are signals of health and vitality because stressor exposure (e.g. early disease) will compromise them (e.g. shorter stature) more than other traits. We provide a large-scale test of this hypothesis for the human male and show that with cross-national and cross-generational improvements in living conditions, where environmental stressors recede, men's gains in height and weight are more than double those of women's, increasing sexual size dimorphism. Our study combines evolutionary biology with measures of human wellbeing, providing novel insights into how socio-ecological factors and sexual selection shape key physical traits.

The question of whether males or females are the more variable sex is long-standing, and yet to be fully answered. We investigate the relationships between body mass and variation across species using a phylogenetically informed analysis of the body mass of 337 species representing six mammalian orders. Within each order, we found that the larger sex is typically the more variable sex, whether male or female, and the variation-size relationship is arguably often close to unity. Thus, size may be the main or even sole driver of variability in at least some orders. Deviations from the expected 1 : 1 relationship emerged, however, in regressions of male : female mass variance against male : female mean mass, for Chiroptera and Rodentia, which both presented hyperallometric relationships suggesting that drivers over and above size influence differences in variation between the sexes. In Chiroptera, most species have larger females. The y -intercept value for Artiodactyla and Primates were significantly greater than 0 suggesting greater male variation in species where the sexes are of commensurable size. Historic belief of exclusively greater male variability may have resulted from a focus on species with intense male-male competition and, thus, larger male body sizes. Our results suggest that it is often size, not sex per se , that influences within-sex variability, although additional sex-specific factors might be present in at least some orders.

Independent of overall achievement, girls' intraindividual academic strength is typically reading, whereas boys' strength is typically mathematics or science. Sex differences in intraindividual strengths are associated with educational and occupational sex disparities in science, technology, engineering, and mathematics (STEM) fields. Paradoxically, these sex differences are larger in more gender-equal countries, but the stability of this paradox is debated. We assessed the stability of the gender-equality paradox in intraindividual strengths, and its relation to wealth, by analyzing the academic achievement of nearly 2.5 million adolescents across 85 countries and regions in five waves (from 2006 to 2018) of the Programme for International Student Assessment (PISA). Girls' intraindividual strength in reading and boys' strength in mathematics and science were stable across countries and waves. Boys' advantage in science as an intraindividual strength was larger in more gender-equal countries, whereas girls' advantage in reading was larger in wealthier countries. The results have implications for reducing sex disparities in STEM fields.

Understanding the magnitudes represented by numerals is a core component of early mathematical development and is often assessed by accuracy in situating numerals and fractions on a number line. Performance on these measures is consistently related to performance in other mathematics domains, but the strength of these relations may be overestimated because general cognitive ability has not been fully controlled in prior studies. The first of two meta-analyses (162 studies, 33,101 participants) confirmed a relation between performance on whole number (r = 0.33) and fractions number (r = 0.41) lines and overall mathematics performance. These relations were generally consistent across content domains (e.g., algebra and computation) and other moderators. The second (71 studies, 14,543 participants) used meta-analytic structural equation modeling to confirm these relations while controlling general cognitive ability (defined by IQ and working memory measures) and, in one analysis, general mathematics competence. The relation between number line performance and general mathematics competence remained significant but reduced (β = 0.13). Controlling general cognitive ability, whole number line performance consistently predicted competence with fractions but not performance on numeracy or computations measures. The results suggest an understanding of the magnitudes represented by whole numbers might be particularly important for students' fractions learning. RESEARCH HIGHLIGHTS: Two meta-analyses examined the link between the number line and mathematics performance. The first revealed significant relations across domains (e.g., algebra and computation). The second controlled for general cognitive ability and resulted in reduced but still significant relations. The relation between number line and fractions performance was stronger than relations to other domains., (© 2024 John Wiley & Sons Ltd.)

Science is among humanity's greatest achievements, yet scientific censorship is rarely studied empirically. We explore the social, psychological, and institutional causes and consequences of scientific censorship (defined as actions aimed at obstructing particular scientific ideas from reaching an audience for reasons other than low scientific quality). Popular narratives suggest that scientific censorship is driven by authoritarian officials with dark motives, such as dogmatism and intolerance. Our analysis suggests that scientific censorship is often driven by scientists, who are primarily motivated by self-protection, benevolence toward peer scholars, and prosocial concerns for the well-being of human social groups. This perspective helps explain both recent findings on scientific censorship and recent changes to scientific institutions, such as the use of harm-based criteria to evaluate research. We discuss unknowns surrounding the consequences of censorship and provide recommendations for improving transparency and accountability in scientific decision-making to enable the exploration of these unknowns. The benefits of censorship may sometimes outweigh costs. However, until costs and benefits are examined empirically, scholars on opposing sides of ongoing debates are left to quarrel based on competing values, assumptions, and intuitions., Competing Interests: Competing interests statement:The authors declare no competing interest.

Meta-analytic structural equation modeling was used to estimate the relative contributions of general cognitive ability or g (defined by executive functions, short-term memory, and intelligence) and basic domain-specific mathematical abilities to performance in more complex mathematics domains. The domain-specific abilities included mathematics fluency (e.g., speed of retrieving basic facts), computational skills (i.e., accuracy at solving multi-step arithmetic, algebra, or geometry problems), and word problems (i.e., mathematics problems presented in narrative form). The core analysis included 448 independent samples and 431,344 participants and revealed that g predicted performance in all three mathematics domains. Mathematics fluency contributed to the prediction of computational skills, and both mathematics fluency and computational skills predicted word problem performance, controlling g . The relative contribution of g was consistently larger than basic domain-specific abilities, although the latter may be underestimated. The patterns were similar across younger and older individuals, individuals with and without a disability (e.g., learning disability), concurrent and longitudinal assessments, and family socioeconomic status, and have implications for fostering mathematical development., Competing Interests: There is no financial/personal interest or belief that could affect our objectivity, and there is no source of potential conflict.

There are consistent correlations between mathematics achievement, attitudes, and anxiety, but the longitudinal relations among these constructs are not well understood nor are sex differences in these relations. To address this gap, mathematics achievement, attitudes, and anxiety were longitudinally assessed for 342 (169 boys) adolescents from 7th to 9th grade, inclusive, and Latent Growth Curve Models were used to assess the relations among these traits and developmental change in them. Spatial abilities (7th, 8th grade) and trait anxiety (8th, 9th grade) were also assessed and used for control for sex differences in these traits. Overall, boys had stronger spatial abilities and more positive mathematics attitudes and were less anxious than girls, but there were no sex differences in mathematics achievement. Across grades, mathematics achievement improved, attitudes became less positive, and anxiety increased for both boys and girls. Higher than average cross-grade growth in mathematics achievement mitigated boys' developmental declines in mathematics attitudes and increases in anxiety. Girls with strong spatial abilities had lower mathematics anxiety, but girls overall maintained higher mathematics anxiety and less positive mathematics attitudes relative to boys, even when they showed strong cross-grade gains in mathematics achievement. The study demonstrated that longitudinal gains in mathematics are associated with cross-grade changes in attitudes and anxiety but with several different developmental patterns for boys and girls.

Adolescents' ( n = 342, 169 boys) general algebra and algebra word problems performance were assessed in 9th grade as were intelligence, academic achievement, working memory, and spatial abilities in prior grades. The adolescents reported on their academic attitudes and anxiety and their teachers reported on their in-class attentive behavior in 7th to 9th grade. There were no sex differences on the general algebra measure or for mathematics achievement, but boys had an advantage on the algebra word problems measure ( d = .51) and for spatial abilities ( d s = .29 to .58). Boys had higher mathematics self-efficacy ( d = .24 to .33), lower mathematics anxiety ( d s = -.31 to -.53) and were less attentive in classrooms ( d s = -.28 to -.37). A series of structural equation models revealed the sex difference for algebra word problems was mediated by spatial abilities and mathematics anxiety, controlling myriad confounds. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The study tested the hypothesis that there are sex differences in the pathways to mathematical development. Three hundred forty-two adolescents (169 boys) were assessed in various mathematics areas from arithmetic fluency to algebra across 6 th to 9 th grade, inclusive, and completed a battery of working memory, spatial, and intelligence measures in middle school. Their middle school and 9 th grade teachers reported on their in-class attentive behavior. There were no sex differences in overall mathematics performance, but boys had advantages on all spatial measures ( d s = .29 to .58) and girls were more attentive in classroom settings ( d s = -.28 to -.37). A series of structural equation models indicated that 6 th - to 9 th -grade mathematical competence was influenced by a combination of general cognitive ability, spatial abilities, and in-class attention. General cognitive ability was important for both sexes but the spatial pathway to mathematical competence was relatively more important for boys and the in-class attention pathway for girls.

Narvaez et al. (2022), in their article "Evolving Evolutionary Psychology," argue that mainstream evolutionary psychology is based on misguided neo-Darwinian adaptationist thinking and an antiquated computationalist, "mind-as-computer" framework and offer their own developmentally informed theory as an alternative. While applauding Narvaez et al. for promoting the role of development in evolutionary explication and as a potential metatheory for psychology, we point out that contemporary evolutionary-developmental accounts address the shortcomings of mainstream evolutionary psychology they describe, while maintaining an adaptationist perspective that includes a central role of evolved, domain-specific information-processing mechanisms. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

We investigated the role of working memory in symbolic and spatial algebra and related tasks across five experiments. Each experiment combined a processing task (expression evaluation, arithmetic, coordinate plane, geometry, or mental rotation) with verbal and spatial memory loads in a dual-task design. Spatial memory was compromised in the presence of more difficult processing tasks, and verbal memory was only compromised in the presence of algebraic tasks. The latter was related to the demands of retaining quantities associated with variables in verbal memory. We suggest that both verbal and spatial working memory retention engage domain-general attention, but that their maintenance mechanisms differ. Verbal memory has attention-based and rehearsal-based mechanisms, and thus sustaining verbal information over a short period is less attention-demanding than holding spatial information. We suggest that effects of a memory load on processing (e.g., x = 6) depend on whether use of maintenance strategies are possible for the specific memory load while carrying out processing. In all, our results indicate that algebraic tasks use domain-general attention and include verbal processing of algebraic variables (i.e., information conveyed in x, y). We discuss the implications for algebra learning and working memory theories. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

We examined longitudinal relations between 1 st -grade cognitive predictors (early nonverbal reasoning, processing speed, listening comprehension, working memory, calculation skill, word-problem solving, word-reading fluency, attentive behavior, and numerical cognition) and 2 nd -grade academic outcomes (calculations, word-problem solving, and word reading) in 370 children ( M age = 6.55 years, SD age = 0.33 years at the start of the study) who were identified as at-risk or not-at-risk for mathematics disability. Path analysis mediation models revealed that numerical cognition, assessed at an intermediary timepoint, mediated the effects of processing speed, working memory, calculation skill, word-problem solving, and attentive behavior on all 3 outcomes. Findings indicate that multiple early domain-general cognitive abilities are related to later mathematics and reading outcomes and that numerical cognition processes, which may track ease of forming symbol-concept associations, predict later performance across both academic domains.

We investigated sex differences in 473,260 adolescents' aspirations to work in things-oriented (e.g., mechanic), people-oriented (e.g., nurse), and STEM (e.g., mathematician) careers across 80 countries and economic regions using the 2018 Programme for International Student Assessment (PISA). We analyzed student career aspirations in combination with student achievement in mathematics, reading, and science, as well as parental occupations and family wealth. In each country and region, more boys than girls aspired to a things-oriented or STEM occupation and more girls than boys to a people-oriented occupation. These sex differences were larger in countries with a higher level of women's empowerment. We explain this counter-intuitive finding through the indirect effect of wealth. Women's empowerment is associated with relatively high levels of national wealth and this wealth allows more students to aspire to occupations they are intrinsically interested in. Implications for better understanding the sources of sex differences in career aspirations and associated policy are discussed., Competing Interests: The authors have declared that no competing interests exist.

Schooling is ubiquitous in the modern world and academic development is now a critical aspect of preparation for adulthood. A step back in time to pre-modern societies and an examination of life in remaining traditional societies today reveals that universal formal schooling is an historically recent phenomenon. This evolutionary and historical recency has profound implications for understanding academic development, including how instructional practices modify evolved or biological primary abilities (e.g., spoken language) to create evolutionarily novel or biologically secondary academic competencies (e.g., reading). We propose the development of secondary abilities promotes the emergence of academic self-concepts that in turn are supported by evolved systems for self-awareness and self-knowledge. Unlike some forms of self-knowledge (e.g., relative physical abilities) that appear to be universal and central to many people's overall self-concept, the relative importance of academic self-concepts are expected to be dependent on explicit social and cultural supports for their valuation. These culturally contingent self-concepts are contrasted with universal social and physical self-concepts, with implications for understanding variation students' relative valuation of academic competencies and their motivations to engage in academic learning., Competing Interests: Conflict of InterestThe authors declare that they have no conflict of interests., (© The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2022.)

The mathematics and reading achievement of 322 adolescents (159 boys) was assessed in seventh and eighth grades, as were their intelligence, working memory, and spatial abilities. Their seventh- and eighth-grade mathematics and English language arts teachers reported on their in-class attentive behavior. The latter emerged as an important predictor of achievement, but more so for mathematics than for reading. Boy were less attentive in classroom settings than girls (d = -.34) and performed better than expected in mathematics given their level of engagement in the classroom. Boys' better-than-expected mathematics achievement was related to advantages on visuospatial measures (ds = .28-.56), which fully mediated a sex difference in mathematics (ds = .27-.28) but not in reading achievement, with control of in-class attentive behavior. The results suggest that boys' advantages in visuospatial skills compensate for lower levels of classroom engagement in the learning of mathematics but not in reading competencies., (Copyright © 2021 Elsevier Inc. All rights reserved.)

The contributions of evolutionary processes to human sex differences are vigorously debated. One counterargument is that the magnitude of many sex differences fluctuates from one context to the next, implying an environment origin. Sexual selection provides a framework for integrating evolutionary processes and environmental influences on the origin and magnitude of sex differences. The dynamics of sexual selection involve competition for mates and discriminative mate choices. The associated traits are typically exaggerated and condition-dependent, that is, their development and expression are very sensitive to social and ecological conditions. The magnitude of sex differences in sexually selected traits should then be largest under optimal social and ecological conditions and shrink as conditions deteriorate. The basics of this framework are described, and its utility is illustrated with discussion of fluctuations in the magnitude of human physical, behavioral, and cognitive sex differences., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Identifying meaningful cognitive and non-cognitive predictors of mathematical competence is critical for developing targeted interventions for students struggling with mathematics. Here, 317 students' short-term verbal memory, verbal and visuospatial working memory, complex spatial abilities, intelligence, and mathematics attitudes and anxiety were assessed, and their teachers reported on their attentive-behavior in seventh-grade mathematics classrooms. Bayesian regression models revealed that complex spatial abilities and in-class attention were the most plausible predictors of seventh-grade mathematics, but not word reading, achievement, controlling for prior achievement. These results were confirmed with multilevel models that revealed interactions between these factors and prior achievement. The largest gains were among students with strong mathematical competencies in sixth-grade, and average or better in-class attention in seventh-grade as well as above average spatial abilities. High mathematics anxiety was associated with lower attention and through this indirectly influenced achievement gains. These results have implications for how to best target interventions for students at risk for long-term difficulties with mathematics.

The study tested the hypotheses that boys will have an advantage learning the fractions number line and this advantage will be mediated by spatial abilities. Fractions number line and, as a contrast, fractions arithmetic performance were assessed for 342 adolescents, as was their intelligence, working memory, and various spatial abilities. Boys showed smaller placement errors on the fractions number line (d = -0.22) and correctly solved more fractions arithmetic problems (d = 0.23) than girls. Working memory and intelligence predicted performance on both fractions measures, and a measure of visuospatial attention uniquely predicted number line performance and fully mediated the sex difference. Visuospatial working memory uniquely predicted fractions arithmetic performance and fully mediated the sex difference. The results help to clarify the nuanced relations between spatial abilities and formal mathematics learning and the sex differences that often emerge in mathematical domains that have a visuospatial component., (© 2020 John Wiley & Sons Ltd.)

Cognitive scientists have determined that there is a set of mechanisms common to all sensory, perceptual, and cognitive abilities and correlated with age- and disease-related declines in cognition. These mechanisms also contribute to the development and functional coherence of the large-scale brain networks that support complex forms of cognition. At the same time, these brain and cognitive patterns are correlated with myriad health outcomes, indicating that at least some of the underlying mechanisms are common to all biological systems. Mitochondrial functions, including cellular energy production and control of oxidative stress, among others, are well situated to explain the relations among the brain, cognition, and health. Here, I provide an overview of the relations among cognitive abilities, associated brain networks, and the importance of mitochondrial energy production for their functioning. These are then linked to the relations between cognition, health, and aging. The discussion closes with implications for better integrating research in cognitive science and cell biology in the context of developing more sensitive measures of age- and disease-related declines in cognition.

Early life adversity is widely recognized as a key risk factor for early developmental perturbations and contributes to the presentation of neuropsychiatric disorders in adulthood. Neurodevelopmental disorders exhibit a strong sex bias in susceptibility, presentation, onset, and severity, although the underlying mechanisms conferring vulnerability are not well understood. Environmental perturbations during pregnancy, such as malnutrition or stress, have been associated with sex-specific reprogramming that contribute to increased disease risk in adulthood, whereby stress and nutritional insufficiency may be additive and further exacerbate poor offspring outcomes. To determine whether maternal supplementation of docosahexanoic acid (DHA) exerts an effect on offspring outcome following exposure to early prenatal stress (EPS), dams were fed a purified 10:1 omega-6/omega-3 diet supplemented with either 1.0% preformed DHA/kg feed weight (DHA-enriched) or no additional DHA (denoted as the control diet, CTL). Dams were administered chronic variable stress during the first week of pregnancy (embryonic day, E0.5-7.5), and developmental milestones were assessed at E 12.5. Exposure to early prenatal stress (EPS) decreased placenta and embryo weight in males, but not females, exposed to the CTL diet. DHA enrichment reversed the sex-specific decrease in placenta and embryo weight following EPS. Early prenatal exposure upregulated expression of genes associated with oxygen and nutrient transport, including hypoxia inducible factor 3α (HIF3α), peroxisome proliferator-activated receptor alpha (PPARα), and insulin-like growth binding factor 1 (IGFBP1), in the placenta of CTL diet males exposed to EPS. DHA enrichment in EPS-exposed animals abrogated the male-specific upregulation of PPARα, HIF3α, and IGFBP1. Taken together, these studies suggest that maternal dietary DHA enrichment may buffer against maternal stress programming of sex-specific outcomes during early development.

The main purpose of this study was to test the effects of word-problem intervention, with versus without embedded language comprehension instruction, on at-risk 1 st graders' word-problem performance. We also isolated the need for a structured approach to word-problem intervention and tested the efficacy of schema-based instruction at 1 st grade. Children (n=391; mean age = 6.53, SD = 0.32) were randomly assigned to 4 conditions: schema-based word-problem intervention with embedded language instruction, the same word-problem intervention but without language comprehension instruction, structured number knowledge intervention without a structured word-problem component, and a control group. Each intervention included 45 30-min sessions. Multilevel models, accounting for classroom and school effects, revealed the efficacy of schema-based word-problem intervention at 1 st grade, with both word-problem conditions outperforming the number knowledge condition and the control group. Yet, word-problem performance was significantly stronger for the schema-based condition with embedded language comprehension instruction compared to the schema-based condition without language comprehension instruction. Number knowledge intervention conveyed no word-problem advantage over the control group, even though all 3 intervention conditions outperformed the control group on arithmetic. Results demonstrate the importance of a structured approach to word-problem intervention; the efficacy of schema-based instruction at 1 st grade; and the added value of language comprehension instruction within word-problem intervention. Results also provide causal evidence on the role of language comprehension in word-problem solving.

Pre-algebra mathematical competencies were assessed for a large and diverse sample of sixth graders ( n = 1,926), including whole number and fractions arithmetic, conceptual understanding of equality and fractions magnitudes, and the fractions number line. The goal was to determine if there were clusters of students with similar patterns of pre-algebra strengths and weaknesses and if variation between clusters was related to mathematics attitudes, anxiety, or for a subsample ( n = 342) some combination of intelligence, working memory, or spatial abilities. Critically, strengths and weaknesses were not uniform across the three identified clusters. Lower-performing students had pronounced deficits in their understanding of mathematical equality, fractions magnitudes, and the fractions number line. Higher-performing students had particular advantages in whole number and fractions arithmetic, and the fractions number line. Students could be reliably placed into clusters based on their mathematics self-efficacy and a combination of intelligence and spatial abilities. The results contribute to our understanding of key aspects of students' mathematical development, highlight areas in need of intervention for at-risk students, and identify cognitive areas in which scaffolds might be incorporated into these interventions.

In response to commentaries, I address questions regarding the proposal that general intelligence ( g ) is a manifestation of the functioning of intramodular and intermodular brain networks undergirded by the efficiency of mitochondrial functioning (Geary 2018). The core issues include the relative contribution of mitochondrial functioning to individual differences in g ; studies that can be used to test associated hypotheses; and, the adaptive function of intelligence from an evolutionary perspective. I attempt to address these and related issues, as well as note areas in which other issues remain to be addressed.

The goal was to identify the domain-general cognitive abilities and academic attitudes that are common and unique to reading and mathematics learning difficulties that in turn will have implications for intervention development. Across seventh and eighth grade, 315 (155 boys) adolescents ( M age = 12.75 years) were administered intelligence, verbal short-term and working memory, and visuospatial memory, attention, and ability measures, along with measures of English and mathematics attitudes and mathematics anxiety. Teachers reported on students' in-class attentive behavior. A combination of Bayesian and multi-level models revealed that intelligence and in-class attentive behavior were common predictors of reading accuracy, reading fluency, and mathematics achievement. Verbal short-term memory was more critical for reading accuracy and fluency, whereas spatial ability and mathematics self-efficacy were more critical for mathematics achievement. The combination of intelligence and in-class attentive behavior discriminated typically achieving students from students with comorbid ( D = 2.44) or mathematics ( D = 1.59) learning difficulties, whereas intelligence, visuospatial attention, and verbal short-term memory discriminated typically achieving students from students with reading disability ( D = 1.08). The combination of in-class attentive behavior, verbal short-term memory, and mathematics self-efficacy discriminated students with mathematics difficulties from their peers with reading difficulties ( D = 1.16). Given the consistent importance of in-class attentive behavior, we conducted post hoc follow-up analyses. The results suggested that students with poor in-class attentive behavior were disengaging from academic learning which in turn contributed to their risk of learning difficulties., (Copyright © 2020 Geary, Hoard, Nugent, Ünal and Scofield.)

Evolutionary theory suggests that commonly found sex differences are largest in healthy populations and smaller in populations that have been exposed to stressors. We tested this idea in the context of men's typical advantage (vs. women) in visuospatial abilities (e.g., mental rotation) and women's typical advantage (vs. men) in social-cognitive (e.g., facial-expression decoding) abilities, as related to frequent binge drinking. Four hundred nineteen undergraduates classified as frequent or infrequent binge drinkers were assessed in these domains. Trial-level multilevel models were used to test a priori Sex × Group (binge drinking) interactions for visuospatial and social-cognitive tasks. Among infrequent binge drinkers, men's typical advantage in visuospatial abilities and women's typical advantage in social-cognitive abilities was confirmed. Among frequent binge drinkers, men's advantage was reduced for one visuospatial task (Δ d = 0.29) and eliminated for another (Δ d = 0.75), and women's advantage on the social-cognitive task was eliminated (Δ d = 0.12). Males who frequently engaged in extreme binges had exaggerated deficits on one of the visuospatial tasks, as did their female counterparts on the social-cognitive task. The results suggest sex-specific vulnerabilities associated with recent, frequent binge drinking, and support an evolutionary approach to the study of these vulnerabilities.

It is well known that far fewer men than women enroll in tertiary education in the United States and other Western nations. Developed nations vary in the degree to which men are underrepresented, but the Organization for Economic Co-operation and Development (OECD) average lies around 45% male students. We use data from the OECD Education at a Glance statistical reports, the Program for International Student Assessment (PISA), and the World Values Survey to explain the degree to which men are underrepresented. Using a multiple regression model, we show that the combination of both the national reading proficiency levels of 15-y-old boys and girls and the social attitudes toward girls attending university can predict the enrollment in tertiary education 5 y later. The model also shows that parity in some countries is a result of boys' poor reading proficiency and negative social attitudes toward girls' education, which suppresses college enrollment in both sexes, but for different reasons. True equity will at the very least require improvement in boys' reading competencies and the liberalization of attitudes regarding women's pursuit of higher education. At this time, there is little reason to expect that the enrollment gap will decrease, given the stagnating reading competencies in most countries., Competing Interests: The authors declare no competing interest., (Copyright © 2020 the Author(s). Published by PNAS.)

We present first-grade, second-grade, and third-grade impacts for a first-grade intervention targeting the conceptual and procedural bases that support arithmetic. At-risk students (average age at pretest = 6.5) were randomly assigned to three conditions: a control group (n = 224) and two variants of the intervention (same conceptual instruction but different forms of practice: speeded [n = 211] vs. nonspeeded [n = 204]). Impacts on all first-grade content outcomes were significant and positive, but no follow-up impacts were significant. Many intervention children achieved average mathematics achievement at the end of third grade, and prior math and reading assessment performance predicted which students will require sustained intervention. Finally, projecting impacts 2 years later based on nonexperimental estimates of effects of first-grade math skills overestimates long-term intervention effects., (© 2018 Society for Research in Child Development.)

In a preschool through first grade longitudinal study, we identified groups of children with persistently low mathematics achievement (n = 14) and children with low achievement in preschool but average achievement in first grade (n = 23). The preschool quantitative developments of these respective groups of children with mathematical learning disability (MLD) and recovered children and a group of typically achieving peers (n = 35) were contrasted, as were their intelligence, executive function, and parental education levels. The core characteristics of the children with MLD were poor executive function and delayed understanding of the cardinal value of number words throughout preschool. These compounded into even more substantive deficits in number and arithmetic at the beginning of first grade. The recovered group had poor executive function and cardinal knowledge during the first year of preschool but showed significant gains during the second year. Despite these gains and average mathematics achievement, the recovered children had subtle deficits with accessing magnitudes associated with numerals and addition combinations (e.g., 5 + 6 = ?) in first grade. The study provides unique insight into domain-general and quantitative deficits in preschool that increase risk for long-term mathematical difficulties., (Copyright © 2019 Elsevier Inc. All rights reserved.)

In a recent theoretical article, I proposed that the efficiency of mitochondrial functioning is the most fundamental biological mechanism contributing to individual differences in general intelligence ( g ; Geary, 2018). The hypothesis accommodates other contributing mechanisms at higher levels of analysis (e.g., brain networks), and is attractive because mitochondrial energy production undergirds the developmental, maintenance, and expression of these other mechanisms and provides a means to link individual differences in g to individual differences in health and successful aging in adulthood. I provide a brief summation here and a few clarifications to the original article.

Sex differences in the strength of the relations between mathematics anxiety, mathematics attitudes and mathematics achievement were assessed concurrently in sixth grade ( n = 1,091, 545 boys) and longitudinally from sixth- to seventh-grade ( n = 190, 97 boys). Mathematics anxiety was composed of two facets, one associated with evaluations and the other for learning more generally. Girls had higher mathematics anxiety for evaluations than did boys ( d s = -.30 to -.52), but not for mathematics learning. In sixth grade, the negative correlation between mathematical competence and mathematics anxiety for evaluations was stronger in girls than in boys. Longitudinally, higher mathematical competence in sixth grade was associated with lower mathematics anxiety for evaluations and better mathematics attitudes in seventh grade for girls but not for boys. The key finding is that adolescent girls' mathematics anxiety and their attitudes toward mathematics are more reflective of their actual mathematical competence than they are for boys. One implication is that relative to boys with low mathematics achievement, girls with low achievement are at higher risk of developing mathematics anxiety and poor attitudes toward mathematics.

Neuroimaging studies of subjects with ADHD typically show altered functional connectivity in prefrontal, striatal, and several temporal brain regions. While the majority of studies have focused on connectivity that is averaged over time, we investigated the temporal dynamics of brain network changes in resting-state fMRI. Using the ADHD-200 consortium, we characterized the time course of latent state changes using Hidden Markov Modeling, and compared state changes between boys and girls with ADHD along with typically developing controls. Sex differences were found in latent state switching, with boys dwelling longer in a given state than girls, and concurrently having fewer overall state transitions. These sex differences were found in children with ADHD and in typically developing controls. Children with ADHD were also found to be more variable in terms of state transitions than controls. These findings add to the growing literature on neural sex differences and may be related to the sex difference in focal versus diffuse attention., Competing Interests: The authors have declared that no competing interests exist.

Sex-specific brain and cognitive deficits emerge with malnutrition, some infectious and neurodegenerative diseases, and often with prenatal or postnatal toxin exposure. These deficits are described in disparate literatures and are generally not linked to one another. Sexual selection may provide a unifying framework that integrates our understanding of these deficits and provides direction for future studies of sex-specific vulnerabilities. Sexually selected traits are those that have evolved to facilitate competition for reproductive resources or that influence mate choices, and are often larger and more complex than other traits. Critically, malnutrition, disease, chronic social stress, and exposure to man-made toxins compromise the development and expression of sexually selected traits more strongly than that of other traits. The fundamental mechanism underlying vulnerability might be the efficiency of mitochondrial energy capture and control of oxidative stress that in turn links these traits to current advances in neuroenergetics, stress endocrinology, and toxicology. The key idea is that the elaboration of these cognitive abilities, with more underlying gray matter or more extensive inter-modular white matter connections, makes them particularly sensitive to disruptions in mitochondrial functioning and oxidative stress. A framework of human sexually selected cognitive abilities and underlying brain systems is proposed and used to organize what is currently known about sex-specific vulnerabilities., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The Strategy Choice Model (SCM) is a highly influential theory of human problem-solving. One strength of this theory is the allowance for both item and person variance to contribute to problem-solving outcomes, but this central tenet of the model has not been empirically tested. Explanatory Item Response Theory (EIRT) provides an ideal approach to testing this core feature of SCM, as it allows for simultaneous estimation of both item and person effects on problem-solving outcomes. We used EIRT to test and confirm this central tenet of the SCM for adolescents' (n = 376) solving of addition problems. The approach also allowed us to identify the strategy choices of adolescents who still struggle with basic arithmetic. The synthesis of SCM theory and EIRT modeling has implications for more fully investigating the sources of individual differences in students' problem solving, and for identifying problem-solving patterns associated with poor academic achievement.

Children's first mathematics concept is their understanding of the quantities represented by number words (cardinal value), and the age at which they achieve this insight predicts their readiness for mathematics learning in school. We provide the first exploration of the factors that influence the age of becoming a cardinal principle knower (CPK), with a longitudinal study of 197 (94 boys) children from the beginning to the end of two years of preschool. Core symbolic and non-symbolic quantitative competencies at the beginning of preschool, as well as measures of intelligence, executive function, preliteracy skills, and parental education were used to predict timing of CPK status. Children who achieved early CPK status had higher IQ scores, knew more count words and numerals, and had a better intuitive understanding of relative quantity than their peers. Children who were delayed CPKs, in contrast, had deficits in executive function and poor preliteracy skills. The results add to our understanding of children's conceptual development in mathematics and have implications for the identification of at-risk children and design of interventions for them.

The Global Gender Gap Index is one of the best-known measures of national gender inequality, used by both academics and policy makers. We argue that that this measure has a number of problems and introduce a simpler measure of national levels of gender inequality. Our proposed measure is based on sex differences in the opportunity to lead a long healthy and satisfied life that is grounded on educational opportunities. The measure better captures variation in gender inequality than other measures, with inclusion of outcomes that can be favorable or unfavorable to either sex, not simply unfavorable to women. We focus on some of the most basic measures available for 134 countries from 2012-2016 (i.e., disadvantages in children's basic education, life satisfaction, and healthy life span) and we relate these to various measures, including the United Nations' Human Development Index. We found that low levels of human development are typically associated with disadvantages for girls and women, while medium and high levels of development are typically associated with disadvantages for boys and men. Countries with the highest levels of human development are closest to gender parity, albeit typically with a slight advantage for women. We argue that the disparities, when they are found, are related to the sexual division of labor (i.e., traditional gender roles) in poorly developed countries as well as the underinvestment in preventative health care in more developed nations., Competing Interests: The authors have declared that no competing interests exist.

Competing Interests: The author declares no conflict of interest.

General intelligence or g is one of the most thoroughly studied concepts in the behavioral sciences. Measures of intelligence are predictive of a wide range of educational, occupational, and life outcomes, including creative productivity and are systematically related to physical health and successful aging. The nexus of relations suggests 1 or several fundamental biological mechanisms underlie g, health, and aging, among other outcomes. Cell-damaging oxidative stress has been proposed as 1 of many potential mechanisms, but the proposal is underdeveloped and does not capture other important mitochondrial functions. I flesh out this proposal and argue that the overall efficiency of mitochondrial functioning is a core component of g; the most fundamental biological mechanism common to all brain and cognitive processes and that contributes to the relations among intelligence, health, and aging. The proposal integrates research on intelligence with models of the centrality of mitochondria to brain development and functioning, neurological diseases, and health more generally. Moreover, the combination of the maternal inheritance of mitochondrial DNA (mtDNA), the evolution of compensatory nuclear DNA, and the inability of evolutionary processes to purge deleterious mtDNA in males may contribute to the sex difference in variability in intelligence and in other cognitive domains. The proposal unifies many now disparate literatures and generates testable predictions for future studies. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Children who achieve an early understanding of the cardinal value of number words (cardinal knowledge) have a superior understanding of the relations among numerals at school entry, controlling other factors (e.g., intelligence). We tested the hypothesis that this pattern emerges because an understanding of cardinal value jump starts children's learning of the relations among numerals. Across two years of preschool, the cardinal knowledge of 179 children (85 boys) was assessed four times, as was their understanding of the relative quantity of Arabic numerals and competence at discriminating nonsymbolic quantities. Children were more accurate on nonsymbolic than numeral comparisons before they understood cardinality, but showed more rapid growth for numeral than nonsymbolic comparisons once they understood cardinality. Moreover, and with the possible exception of very small numerals (<5), before they understood cardinality children were no better than chance in their numeral comparisons, but greatly exceeded chance once they understood cardinality. These patterns were independent of the age at which children became cardinal principle knowers and independent of intelligence, executive function, and preliteracy skills. More broadly, the results provide a developmental bridge between cardinal knowledge and school-entry number knowledge., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Previous studies suggest that the sophistication of the strategies children use to solve arithmetic problems is related to a more basic understanding of number, but they have not examined the relation between number knowledge in preschool and strategy choices at school entry. Accordingly, the symbolic and nonsymbolic quantitative knowledge of 134 children (65 boys) was assessed at the beginning of preschool and in kindergarten, and the sophistication of the strategies they used to solve addition problems was assessed at the beginning of first grade. Using a combination of Bayes and standard regression models, we found that children's understanding of the cardinal value of number words at the beginning of preschool predicted the sophistication of their strategy choices 3 years later, controlling for other factors. The relation between children's early understanding of cardinality and their strategy choices was mediated by their symbolic and nonsymbolic quantitative knowledge in kindergarten. The results suggest that sophisticated strategy choices emerge from children's developing understanding of the relations among numbers, in keeping with the overlapping waves model., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The underrepresentation of girls and women in science, technology, engineering, and mathematics (STEM) fields is a continual concern for social scientists and policymakers. Using an international database on adolescent achievement in science, mathematics, and reading ( N = 472,242), we showed that girls performed similarly to or better than boys in science in two of every three countries, and in nearly all countries, more girls appeared capable of college-level STEM study than had enrolled. Paradoxically, the sex differences in the magnitude of relative academic strengths and pursuit of STEM degrees rose with increases in national gender equality. The gap between boys' science achievement and girls' reading achievement relative to their mean academic performance was near universal. These sex differences in academic strengths and attitudes toward science correlated with the STEM graduation gap. A mediation analysis suggested that life-quality pressures in less gender-equal countries promote girls' and women's engagement with STEM subjects.