The Science of Sex Differences in Science and Mathematics

Age group and sex differences in performance on a computerized neurocognitive battery in children age 8-21

OBJECTIVE

Examine age group effects and sex differences by applying a comprehensive computerized battery of identical behavioral measures linked to brain systems in youths that were already genotyped. Such information is needed to incorporate behavioral data as neuropsychological "biomarkers" in large-scale genomic studies.

METHOD

We developed and applied a brief computerized neurocognitive battery that provides measures of performance accuracy and response time for executive-control, episodic memory, complex cognition, social cognition, and sensorimotor speed domains. We tested a population-based sample of 3,500 genotyped youths ages 8-21 years.

RESULTS

Substantial improvement with age occurred for both accuracy and speed, but the rates varied by domain. The most pronounced improvement was noted in executive control functions, specifically attention, and in motor speed, with some effect sizes exceeding 1.8 standard deviation units. The least pronounced age group effect was in memory, where only face memory showed a large effect size on improved accuracy. Sex differences had much smaller effect sizes but were evident, with females outperforming males on attention, word and face memory, reasoning speed, and all social cognition tests and males outperforming females in spatial processing and sensorimotor and motor speed. These sex differences in most domains were seen already at the youngest age groups, and age group × sex interactions indicated divergence at the oldest groups with females becoming faster but less accurate than males.

CONCLUSIONS

The results indicate that cognitive performance improves substantially in this age span, with large effect sizes that differ by domain. The more pronounced improvement for executive and reasoning domains than for memory suggests that memory capacities have reached their apex before age 8. Performance was sexually modulated and most sex differences were apparent by early adolescence.

Spatial anxiety relates to spatial abilities as a function of working memory in children

Spatial ability is a strong predictor of students' pursuit of higher education in science and mathematics. However, very little is known about the affective factors that influence individual differences in spatial ability, particularly at a young age. We examine the role of spatial anxiety in young children's performance on a mental rotation task. We show that even at a young age, children report experiencing feelings of nervousness at the prospect of engaging in spatial activities. Moreover, we show that these feelings are associated with reduced mental rotation ability among students with high but not low working memory (WM). Interestingly, this WM × spatial anxiety interaction was only found among girls. We discuss these patterns of results in terms of the problem-solving strategies that boys versus girls use in solving mental rotation problems.

The distance between Mars and Venus: measuring global sex differences in personality

BACKGROUND

Sex differences in personality are believed to be comparatively small. However, research in this area has suffered from significant methodological limitations. We advance a set of guidelines for overcoming those limitations: (a) measure personality with a higher resolution than that afforded by the Big Five; (b) estimate sex differences on latent factors; and (c) assess global sex differences with multivariate effect sizes. We then apply these guidelines to a large, representative adult sample, and obtain what is presently the best estimate of global sex differences in personality.

METHODOLOGY/PRINCIPAL FINDINGS

Personality measures were obtained from a large US sample (N = 10,261) with the 16PF Questionnaire. Multigroup latent variable modeling was used to estimate sex differences on individual personality dimensions, which were then aggregated to yield a multivariate effect size (Mahalanobis D). We found a global effect size D = 2.71, corresponding to an overlap of only 10% between the male and female distributions. Even excluding the factor showing the largest univariate ES, the global effect size was D = 1.71 (24% overlap). These are extremely large differences by psychological standards.

SIGNIFICANCE

The idea that there are only minor differences between the personality profiles of males and females should be rejected as based on inadequate methodology.

Are systemizing and autistic traits related to talent and interest in mathematics and engineering? Testing some of the central claims of the empathizing-systemizing theory

In two experiments, we tested some of the central claims of the empathizing-systemizing (E-S) theory. Experiment 1 showed that the systemizing quotient (SQ) was unrelated to performance on a mathematics test, although it was correlated with statistics-related attitudes, self-efficacy, and anxiety. In Experiment 2, systemizing skills, and gender differences in these skills, were more strongly related to spatial thinking styles than to SQ. In fact, when we partialled the effect of spatial thinking styles, SQ was no longer related to systemizing skills. Additionally, there was no relationship between the Autism Spectrum Quotient (AQ) and the SQ, or skills and interest in mathematics and mechanical reasoning. We discuss the implications of our findings for the E-S theory, and for understanding the autistic cognitive profile.

Early puzzle play: a predictor of preschoolers' spatial transformation skill

Individual differences in spatial skill emerge prior to kindergarten entry. However, little is known about the early experiences that may contribute to these differences. The current study examined the relation between children's early puzzle play and their spatial skill. Children and parents (n = 53) were observed at home for 90 min every 4 months (6 times) between 2 and 4 years of age (26 to 46 months). When children were 4 years 6 months old, they completed a spatial task involving mental transformations of 2-dimensional shapes. Children who were observed playing with puzzles performed better on this task than those who did not, controlling for parent education, income, and overall parent word types. Moreover, among those children who played with puzzles, frequency of puzzle play predicted performance on the spatial transformation task. Although the frequency of puzzle play did not differ for boys and girls, the quality of puzzle play (a composite of puzzle difficulty, parent engagement, and parent spatial language) was higher for boys than for girls. In addition, variation in puzzle play quality predicted performance on the spatial transformation task for girls but not for boys. Implications of these findings as well as future directions for research on the role of puzzle play in the development of spatial skill are discussed.

Gender development and the human brain

Convincing evidence indicates that prenatal exposure to the gonadal hormone, testosterone, influences the development of children's sex-typical toy and activity interests. In addition, growing evidence shows that testosterone exposure contributes similarly to the development of other human behaviors that show sex differences, including sexual orientation, core gender identity, and some, though not all, sex-related cognitive and personality characteristics. In addition to these prenatal hormonal influences, early infancy and puberty may provide additional critical periods when hormones influence human neurobehavioral organization. Sex-linked genes could also contribute to human gender development, and most sex-related characteristics are influenced by socialization and other aspects of postnatal experience, as well. Neural mechanisms underlying the influences of gonadal hormones on human behavior are beginning to be identified. Although the neural mechanisms underlying experiential influences remain largely uninvestigated, they could involve the same neural circuitry as that affected by hormones.

A Theory of Sex Differences in Technical Aptitude and Some Supporting Evidence

In this article, I present a theory that explains the origin of sex differences in technical aptitudes. The theory takes as proven that there are no sex differences in general mental ability (GMA), and it postulates that sex differences in technical aptitude (TA) stem from differences in experience in technical areas, which is in turn based on sex differences in technical interests. Using a large data set, I tested and found support for four predictions made by this theory: (a) the construct level correlation between technical aptitude and GMA is larger for females than males, (b) the observed and true score variability of technical aptitude is greater among males than females, (c) at every level of GMA females have lower levels of technical aptitude, and (d) technical aptitude measures used as estimates of GMA for decision purposes would result in underestimation of GMA levels for girls and women. Given that GMA carries the weight of prediction of job performance, the support found for this last prediction suggests that, for many jobs, technical aptitude tests may underpredict the job performance of female applicants and employees. Future research should examine this question.

Rethinking Giftedness and Gifted Education

For nearly a century, scholars have sought to understand, measure, and explain giftedness. Succeeding theories and empirical investigations have often built on earlier work, complementing or sometimes clashing over conceptions of talent or contesting the mechanisms of talent development. Some have even suggested that giftedness itself is a misnomer, mistaken for the results of endless practice or social advantage. In surveying the landscape of current knowledge about giftedness and gifted education, this monograph will advance a set of interrelated arguments: The abilities of individuals do matter, particularly their abilities in specific talent domains; different talent domains have different developmental trajectories that vary as to when they start, peak, and end; and opportunities provided by society are crucial at every point in the talent-development process. We argue that society must strive to promote these opportunities but that individuals with talent also have some responsibility for their own growth and development. Furthermore, the research knowledge base indicates that psychosocial variables are determining influences in the successful development of talent. Finally, outstanding achievement or eminence ought to be the chief goal of gifted education. We assert that aspiring to fulfill one’s talents and abilities in the form of transcendent creative contributions will lead to high levels of personal satisfaction and self-actualization as well as produce yet unimaginable scientific, aesthetic, and practical benefits to society.

To frame our discussion, we propose a definition of giftedness that we intend to be comprehensive. Giftedness is the manifestation of performance that is clearly at the upper end of the distribution in a talent domain even relative to other high-functioning individuals in that domain. Further, giftedness can be viewed as developmental in that in the beginning stages, potential is the key variable; in later stages, achievement is the measure of giftedness; and in fully developed talents, eminence is the basis on which this label is granted. Psychosocial variables play an essential role in the manifestation of giftedness at every developmental stage. Both cognitive and psychosocial variables are malleable and need to be deliberately cultivated.

Our goal here is to provide a definition that is useful across all domains of endeavor and acknowledges several perspectives about giftedness on which there is a fairly broad scientific consensus. Giftedness (a) reflects the values of society; (b) is typically manifested in actual outcomes, especially in adulthood; (c) is specific to domains of endeavor; (d) is the result of the coalescing of biological, pedagogical, psychological, and psychosocial factors; and (e) is relative not just to the ordinary (e.g., a child with exceptional art ability compared to peers) but to the extraordinary (e.g., an artist who revolutionizes a field of art).

In this monograph, our goal is to review and summarize what we have learned about giftedness from the literature in psychological science and suggest some directions for the field of gifted education. We begin with a discussion of how giftedness is defined (see above). In the second section, we review the reasons why giftedness is often excluded from major conversations on educational policy, and then offer rebuttals to these arguments. In spite of concerns for the future of innovation in the United States, the education research and policy communities have been generally resistant to addressing academic giftedness in research, policy, and practice. The resistance is derived from the assumption that academically gifted children will be successful no matter what educational environment they are placed in, and because their families are believed to be more highly educated and hold above-average access to human capital wealth. These arguments run counter to psychological science indicating the need for all students to be challenged in their schoolwork and that effort and appropriate educational programing, training and support are required to develop a student’s talents and abilities. In fact, high-ability students in the United States are not faring well on international comparisons. The scores of advanced students in the United States with at least one college-educated parent were lower than the scores of students in 16 other developed countries regardless of parental education level.

In the third section, we summarize areas of consensus and controversy in gifted education, using the extant psychological literature to evaluate these positions. Psychological science points to several variables associated with outstanding achievement. The most important of these include general and domain-specific ability, creativity, motivation and mindset, task commitment, passion, interest, opportunity, and chance. Consensus has not been achieved in the field however in four main areas: What are the most important factors that contribute to the acuities or propensities that can serve as signs of potential talent? What are potential barriers to acquiring the “gifted” label? What are the expected outcomes of gifted education? And how should gifted students be educated?

In the fourth section, we provide an overview of the major models of giftedness from the giftedness literature. Four models have served as the foundation for programs used in schools in the United States and in other countries. Most of the research associated with these models focuses on the precollegiate and early university years. Other talent-development models described are designed to explain the evolution of talent over time, going beyond the school years into adult eminence (but these have been applied only by out-of-school programs as the basis for educating gifted students).

In the fifth section we present methodological challenges to conducting research on gifted populations, including definitions of giftedness and talent that are not standardized, test ceilings that are too low to measure progress or growth, comparison groups that are hard to find for extraordinary individuals, and insufficient training in the use of statistical methods that can address some of these challenges.

In the sixth section, we propose a comprehensive model of trajectories of gifted performance from novice to eminence using examples from several domains. This model takes into account when a domain can first be expressed meaningfully—whether in childhood, adolescence, or adulthood. It also takes into account what we currently know about the acuities or propensities that can serve as signs of potential talent. Budding talents are usually recognized, developed, and supported by parents, teachers, and mentors. Those individuals may or may not offer guidance for the talented individual in the psychological strengths and social skills needed to move from one stage of development to the next. We developed the model with the following principles in mind: Abilities matter, domains of talent have varying developmental trajectories, opportunities need to be provided to young people and taken by them as well, psychosocial variables are determining factors in the successful development of talent, and eminence is the aspired outcome of gifted education.

In the seventh section, we outline a research agenda for the field. This agenda, presented in the form of research questions, focuses on two central variables associated with the development of talent—opportunity and motivation—and is organized according to the degree to which access to talent development is high or low and whether an individual is highly motivated or not.

Finally, in the eighth section, we summarize implications for the field in undertaking our proposed perspectives. These include a shift toward identification of talent within domains, the creation of identification processes based on the developmental trajectories of talent domains, the provision of opportunities along with monitoring for response and commitment on the part of participants, provision of coaching in psychosocial skills, and organization of programs around the tools needed to reach the highest possible levels of creative performance or productivity.

Gendered occupational interests: prenatal androgen effects on psychological orientation to Things versus People

There is considerable interest in understanding women's underrepresentation in science, technology, engineering, and mathematics careers. Career choices have been shown to be driven in part by interests, and gender differences in those interests have generally been considered to result from socialization. We explored the contribution of sex hormones to career-related interests, in particular studying whether prenatal androgens affect interests through psychological orientation to Things versus People. We examined this question in individuals with congenital adrenal hyperplasia (CAH), who have atypical exposure to androgens early in development, and their unaffected siblings (total N=125 aged 9 to 26 years). Females with CAH had more interest in Things versus People than did unaffected females, and variations among females with CAH reflected variations in their degree of androgen exposure. Results provide strong support for hormonal influences on interest in occupations characterized by working with Things versus People.

Adolescent girls' experiences and gender-related beliefs in relation to their motivation in math/science and english

Although the gender gap has dramatically narrowed in recent decades, women remain underrepresented in many science, technology, engineering, and mathematics (STEM) fields. This study examined social and personal factors in relation to adolescent girls' motivation in STEM (math/science) versus non-STEM (English) subjects. An ethnically diverse sample of 579 girls ages 13-18 years (M = 15) in the U.S. completed questionnaires measuring their academic achievement, ability beliefs, values, and experiences. Social and personal factors were hypothesized to predict motivation (expectancy-value) differently in math/science (M/S) and English. Social factors included perceived M/S and English support from parents and peers. Personal factors included facets of gender identity (felt conformity pressure, gender typicality, gender-role contentedness), gender-related attitudes, and exposure to feminism. In addition, grades, age, parents' education, and ethnicity were controlled. Girls' M/S motivation was positively associated with mother M/S support, peer M/S support, gender-egalitarian beliefs, and exposure to feminism; it was negatively related to peer English support. Girls' English motivation was positively associated with peer English support as well as felt pressure from parents; it was negatively related to peer M/S support and felt peer pressure. The findings suggest that social and personal factors may influence girls' motivation in domain-specific ways.

Sexing the brain: the science and pseudoscience of sex differences

A recent upsurge in unitary biological explanations for gender differences in behavior (i.e. that they are "hard-wired" in the genetic code), put forward not only in books written for a general audience but also in scientific papers, makes it important to examine the fallacies of these ideas. Such genetic and hormonal explanations of human behavior, formulated with little consideration of the influences of experience, and often without taking experience into account at all, are part of a new wave of genetic explanations for a broad range of human behavior, as explained in the paper. These ideas are far from new; moreover, they are pseudoscientific and are used for political influence under the guise of science. They are a conservative social force that maintains social and educational inequalities between women and men. This paper explains that causal explanations of differences between the sexes are of two completely different types: unitary (genetic determinist) versus interactive explanations. The false reasoning used to support genetic determinist explanations of sex differences in behavior is discussed. To illustrate what biology really tells us about gender differentiation, the paper discusses the interactive roles of genetic, hormonal and environmental influences on the development of gender differences. These interactions are illustrated using two model biological systems (e.g. the intertwined influences of genes, sex hormones and experience on the development of sex differences in behavior in rats, and sex differences in neuronal connections in chickens). There is plenty of scientific evidence to show the complex interactive, and ever changing, influences of experience and genes that take place as an organism develops and throughout its life. Malleability of brain and behavior can be shown clearly using animal models, and the processes involved apply also to the development of brain and behavior in humans. We diminish our understanding of the functions of a host of contributing factors to gender differentiation by parceling out the largest portion of control to the genes. The biology and behavior of humans is dynamic and flexible and need not restrict women to inferior positions in society.

Kindergarten children's sensitivity to geometry in maps

Geometrical concepts are critical to a host of human cognitive achievements, from maps to measurement to mathematics, and both the development of these concepts, and their variation by gender, have long been studied. Most studies of geometrical reasoning, however, present children with materials containing both geometric and non-geometric information, and with tasks that are open to multiple solution strategies. Here we present kindergarten children with a task requiring a focus on geometry: navigation in a small-scale space by a purely geometric map. Children spontaneously extracted and used relationships of both distance and angle in the maps, without prior demonstration, instruction, or feedback, but they failed to use the sense information that distinguishes an array from its mirror image. Children of both genders showed a common profile of performance, with boys showing no advantage on this task. These findings provide evidence that some map-reading abilities arise prior to formal instruction, are common to both genders, and are used spontaneously to guide children's spatial behavior.

Can Sex Differences in Science Be Tied to the Long Reach of Prenatal Hormones? Brain Organization Theory, Digit Ratio (2D/4D), and Sex Differences in Preferences and Cognition

Brain organization theory posits a cascade of physiological and behavioral changes initiated and shaped by prenatal hormones. Recently, this theory has been associated with outcomes including gendered toy preference, 2D/4D digit ratio, personality characteristics, sexual orientation, and cognitive profile (spatial, verbal, and mathematical abilities). We examine the evidence for this claim, focusing on 2D/4D and its putative role as a biomarker for organizational features that influence cognitive abilities/interests predisposing males toward mathematically and spatially intensive careers. Although massive support exists for early brain organization theory overall, there are myriad inconsistencies, alternative explanations, and outright contradictions that must be addressed while still taking the entire theory into account. Like a fractal within the larger theory, the 2D/4D hypothesis mirrors this overall support on a smaller scale while likewise suffering from inconsistencies (positive, negative, and sex-dependent correlations), alternative explanations (2D/4D related to spatial preferences rather than abilities per se), and contradictions (feminine 2D/4D in men associated with higher spatial ability). Using the debate over brain organization theory as the theoretical stage, we focus on 2D/4D evidence as an increasingly important player on this stage, a demonstrative case in point of the evidential complexities of the broader debate, and an increasingly important topic in its own right.

Can Sex Differences in Science Be Tied to the Long Reach of Prenatal Hormones? Brain Organization Theory, Digit Ratio (2D/4D), and Sex Differences in Preferences and Cognition

Brain organization theory posits a cascade of physiological and behavioral changes initiated and shaped by prenatal hormones. Recently, this theory has been associated with outcomes including gendered toy preference, 2D/4D digit ratio, personality characteristics, sexual orientation, and cognitive profile (spatial, verbal, and mathematical abilities). We examine the evidence for this claim, focusing on 2D/4D and its putative role as a biomarker for organizational features that influence cognitive abilities/interests predisposing males toward mathematically and spatially intensive careers. Although massive support exists for early brain organization theory overall, there are myriad inconsistencies, alternative explanations, and outright contradictions that must be addressed while still taking the entire theory into account. Like a fractal within the larger theory, the 2D/4D hypothesis mirrors this overall support on a smaller scale while likewise suffering from inconsistencies (positive, negative, and sex-dependent correlations), alternative explanations (2D/4D related to spatial preferences rather than abilities per se), and contradictions (feminine 2D/4D in men associated with higher spatial ability). Using the debate over brain organization theory as the theoretical stage, we focus on 2D/4D evidence as an increasingly important player on this stage, a demonstrative case in point of the evidential complexities of the broader debate, and an increasingly important topic in its own right.

Gender differences in spatial ability of young children: the effects of training and processing strategies

A sample of 116 children (M=6 years 7 months) in Grade 1 was randomly assigned to experimental (n=60) and control (n=56) groups, with equal numbers of boys and girls in each group. The experimental group received a program aimed at improving representation and transformation of visuospatial information, whereas the control group received a substitute program. All children were administered mental rotation tests before and after an intervention program and a Global-Local Processing Strategies test before the intervention. The results revealed that initial gender differences in spatial ability disappeared following treatment in the experimental but not in the control group. Gender differences were moderated by strategies used to process visuospatial information. Intervention and processing strategies were essential in reducing gender differences in spatial abilities.

Sex-related variation in human behavior and the brain

Male and female fetuses differ in testosterone concentrations beginning as early as week 8 of gestation. This early hormone difference exerts permanent influences on brain development and behavior. Contemporary research shows that hormones are particularly important for the development of sex-typical childhood behavior, including toy choices, which until recently were thought to result solely from sociocultural influences. Prenatal testosterone exposure also appears to influence sexual orientation and gender identity, as well as some, but not all, sex-related cognitive, motor and personality characteristics. Neural mechanisms responsible for these hormone-induced behavioral outcomes are beginning to be identified, and current evidence suggests involvement of the hypothalamus and amygdala, as well as interhemispheric connectivity, and cortical areas involved in visual processing.

Latina and European American Girls' Experiences with Academic Sexism and their Self-Concepts in Mathematics and Science During Adolescence

The study investigated Latina and European American adolescent girls’ (N = 345, M = 15.2 years, range = 13 to 18) experiences with academic sexism in mathematics and science (M/S) and their M/S perceived competence and M/S value (liking and importance). M/S academic sexism was based on girls’ reported experiences hearing sexist comments about girls’ abilities in math and science. Older European American adolescents, and both younger and older Latina adolescents, who experienced several instances of academic sexism felt less competent in M/S than girls who experienced less sexism (controlling for M/S grades). In addition, among older girls (regardless of ethnicity), those who experienced several instances of academic sexism valued M/S less than girls who experienced less sexism.

Sex differences in mental rotation and line angle judgments are positively associated with gender equality and economic development across 53 nations

Mental rotation and line angle judgment performance were assessed in more than 90,000 women and 111,000 men from 53 nations. In all nations, men's mean performance exceeded women's on these two visuospatial tasks. Gender equality (as assessed by United Nations indices) and economic development (as assessed by per capita income and life expectancy) were significantly associated, across nations, with larger sex differences, contrary to the predictions of social role theory. For both men and women, across nations, gender equality and economic development were significantly associated with better performance on the two visuospatial tasks. However, these associations were stronger for the mental rotation task than for the line angle judgment task, and they were stronger for men than for women. Results were discussed in terms of evolutionary, social role, and stereotype threat theories of sex differences.

The etiology of diverse receptive language skills at 12 years

PURPOSE

In the 2nd decade of life, language skills expand in both quantitative and qualitative ways. The etiology of these new skills and the relationships among them have been little explored.

METHOD

Taking advantage of widespread access to inexpensive and fast Internet connections in the United Kingdom, we administered four Web-based measures of receptive language development--Vocabulary, Listening Grammar, Figurative Language, and Making Inferences--to a sample of 12-year-old twin pairs (N=4,892) participating in the Twins Early Development Study (TEDS; Oliver & Plomin, 2007).

RESULTS

The 4 measures showed moderate phenotypic intercorrelation. All 4 showed moderate genetic influence (a2 between .25 and .36) and low shared environmental influence (c2 between .13 and .19). The median genetic correlation among the 4 measures was .87, indicating strong genetic overlap among them. A latent factor score for Language, based on the common variance among the measures, showed substantial genetic influence (a2=.59) and moderate shared environmental influence (c2=.28). A small but significant sex difference favored females on the Listening Grammar and Making Inferences tests, but there was no evidence for sex differences in the etiology of any of the measures.

CONCLUSION

Despite the emergence of new skills at this developmental period, from the etiological perspective, language skills remain relatively undifferentiated at an etiological level.

Seeking congruity between goals and roles: a new look at why women opt out of science, technology, engineering, and mathematics careers

Although women have nearly attained equality with men in several formerly male-dominated fields, they remain underrepresented in the fields of science, technology, engineering, and mathematics (STEM). We argue that one important reason for this discrepancy is that STEM careers are perceived as less likely than careers in other fields to fulfill communal goals (e.g., working with or helping other people). Such perceptions might disproportionately affect women's career decisions, because women tend to endorse communal goals more than men. As predicted, we found that STEM careers, relative to other careers, were perceived to impede communal goals. Moreover, communal-goal endorsement negatively predicted interest in STEM careers, even when controlling for past experience and self-efficacy in science and mathematics. Understanding how communal goals influence people's interest in STEM fields thus provides a new perspective on the issue of women's representation in STEM careers.

The Flynn Effect within Subgroups in the U.S.: Gender, Race, Income, Education, and Urbanization Differences in the NLSY-Children Data

Although the Flynn Effect has been studied widely across cultural, geographic, and intellectual domains, and many explanatory theories have been proposed, little past research attention has been paid to subgroup differences. Rodgers and Wänström (2007) identified an aggregate-level Flynn Effect (FE) at each age between 5 and 13 in the Children of the National Longitudinal Survey of Youth (NLSYC) PIAT-Math data. FE patterns were not obtained for Reading Recognition, Reading Comprehension, or Digit Span, consistent with past FE research suggesting a closer relationship to fluid intelligence measures of problem solving and analytic reasoning than to crystallized measures of verbal comprehension and memory. These prior findings suggest that the NLSYC data can be used as a natural laboratory to study more subtle FE patterns within various demographic subgroups. We test for subgroup Flynn Effect differences by gender, race/ethnicity, maternal education, household income, and urbanization. No subgroups differences emerged for three demographic categories. However, children with more educated (especially college educated) mothers and/or children born into higher income households had an accelerated Flynn effect in their PIAT-M scores compared to cohort peers with lower educated mothers or lower income households. We interpret both the positive and the null findings in relation to previous theoretical explanations.

Improving Oral Language and Literacy Skills in Preschool Children from Disadvantaged Backgrounds: Remembering, Writing, Reading (RWR)

Most reading disabilities can be traced to difficulties acquiring oral language during preschool years due to insufficient linguistic stimulation. The present 2-year project aimed to improve the literacy-related oral language skills of 48 low-income, primarily ELL 4-year-old children in local public preschool by providing for individual conversational experiences with trained university students. Their results were compared to 48 peers at two comparable preschools. Children were tested in the fall and spring on multiple measures. Throughout the year, intervention children met with volunteers each week (26 weeks) for 20 minutes to dictate personal narratives. The control group received the regular public school preschool curriculum only. The improvement of intervention children on multiple measures of oral language ability—notably vocabulary and quality of narrative—was significantly greater than that of their peers.

Sex Differences in Effects of Testing Medium and Response Format on a Visuospatial Task

Sex differences on visuospatial tests are among the most reliably replicated. It is unclear to what extent these performance differences reflect underlying differences in skills or testing factors. To assess whether testing medium and response format affect visuospatial sex differences, performances of introductory psychology students (100 men, 104 women) were examined on a visuospatial task presented in paper-and-pencil and tablet computer forms. Both sexes performed better when tested on paper, although men outperformed women. The introduction of an open-ended component to the visuospatial task eliminated sex differences when prior spatial experiences were controlled, but men outperformed women when prior spatial experiences were not considered. In general, the open-ended version and computerized format of the test diminished performance, suggesting that response format and medium are testing factors that influence visuospatial abilities.

Sex Differences in School Science Performance from Middle Childhood to Early Adolescence

We investigated whether the sexes differ in science performance before they make important course and career selections. We collected teacher-report data from a sample of children from the Twins Early Development Study (TEDS) assessed at ages 9, 10 and 12 years (N>2500 pairs). In addition we developed a test of scientific enquiry and administered it to a sub-sample of TEDS (n=1135; age=14 years). We found no evidence for mean sex differences in science performance assessed by teachers, or by a test of scientific enquiry, although boys were somewhat more variable. At a time when adolescents are making important course choices, girls are performing just as well as boys.

Genes and brain sex differences

Throughout development, numerous biological events occur that differentially affect males and females. Specifically, sex-determining genes that are triggered by the sex-chromosome complement initiate a series of events that determine an organism's sex and lead to the differentiation of the body in sex-specific ways. Such events contribute to many unique sex differences, including the susceptibility to different diseases. Although it was believed that sex hormones singularly differentiated the brain and body, there is emerging research showing that genes also play a direct role. In this chapter, we review this line of work and focus on the use of a unique mouse model that separates the effect of gonadal hormones and sex chromosomes. As genetic technology continues to advance, our understanding of the role that hormones and genes play in sex differences can be used to advance the physical and mental health of both men and women.

Stereotype Threat and Gender Differences in Performance on a Novel Visuospatial Task

Stereotype threat research has shown that being a member of a negatively stereotyped group may result in impaired performance on tests of skills thought to be relevant to the stereotype. This study investigated whether stereotype threat influences gender differences in performance on a novel test of visuospatial ability. Undergraduates ( N = 194) were told that men outperform women on the test (explicit threat), were given no gender-relevant information (implicit threat), or were told that men and women do not differ (nullified stereotype). Although men outperformed women in the explicit and implicit stereotype threat groups, women's performance did not differ significantly from men's when told there is no gender difference. The effect was most pronounced for difficult line judgments. Although stereotypes regarding visuospatial ability may be less culturally salient than those of other cognitive abilities, these findings suggest that they influence performance nonetheless. Implications for optimizing cognitive test performance are discussed.

Variation in orbitofrontal cortex volume: relation to sex, emotion regulation and affect

Sex differences in brain structure have been examined extensively but are not completely understood, especially in relation to possible functional correlates. Our two aims in this study were to investigate sex differences in brain structure, and to investigate a possible relation between orbitofrontal cortex subregions and affective individual differences. We used tensor-based morphometry to estimate local brain volume from MPRAGE images in 117 healthy right-handed adults (58 female), age 18-40 years. We entered estimates of local brain volume as the dependent variable in a GLM, controlling for age, intelligence and whole-brain volume. Men had larger left planum temporale. Women had larger ventromedial prefrontal cortex (vmPFC), right lateral orbitofrontal (rlOFC), cerebellum, and bilateral basal ganglia and nearby white matter. vmPFC but not rlOFC volume covaried with self-reported emotion regulation strategies (reappraisal, suppression), expressivity of positive emotions (but not of negative), strength of emotional impulses, and cognitive but not somatic anxiety. vmPFC volume statistically mediated sex differences in emotion suppression. The results confirm prior reports of sex differences in orbitofrontal cortex structure, and are the first to show that normal variation in vmPFC volume is systematically related to emotion regulation and affective individual differences.

A cognitive neuroscience-based computerized battery for efficient measurement of individual differences: standardization and initial construct validation

There is increased need for efficient computerized methods to collect reliable data on a range of cognitive domains that can be linked to specific brain systems. Such need arises in functional neuroimaging studies, where individual differences in cognitive performance are variables of interest or serve as confounds. In genetic studies of complex behavior, which require particularly large samples, such trait measures can serve as endophenotypes. Traditional neuropsychological tests, based on clinical pathological correlations, are protracted, require extensive training in administration and scoring, and leave lengthy paper trails (double-entry for analysis). We present a computerized battery that takes an average of 1h and provides measures of accuracy and speed on 9 neurocognitive domains. They are cognitive neuroscience-based in that they have been linked experimentally to specific brain systems with functional neuroimaging studies. We describe the process of translating tasks used in functional neuroimaging to tests for assessing individual differences. Data are presented on each test with samples ranging from 139 (81 female) to 536 (311 female) of carefully screened healthy individuals ranging in age from 18 to 84. Item consistency was established with acceptable to high Cronbach alpha coefficients. Inter-item correlations were moderate to high within domain and low to nil across domains, indicating construct validity. Initial criterion validity was demonstrated by sensitivity to sex differences and the effects of age, education and parental education. These results encourage the use of this battery in studies needing an efficient assessment of major neurocognitive domains such as multi-site genetic studies and clinical trials.