Prenatal testosterone does not explain sex differences in spatial ability

Testosterone, gender identity and gender-stereotyped personality attributes

Sex/gender differences in personality associated with gender stereotyped behavior are widely studied in psychology yet remain a subject of ongoing debate. Exposure to testosterone during developmental periods is considered to be a primary mediator of many sex/gender differences in behavior. Extensions of this research has led to both lay beliefs and initial research about individual differences in basal testosterone in adulthood relating to "masculine" personality. In this study, we explored the relationships between testosterone, gender identity, and gender stereotyped personality attributes in a sample of over 400 university students (65 % female assigned at birth). Participants provided ratings of their self-perceived masculinity and femininity, resulting in a continuous measure of gender identity, and a set of agentic and communal personality attributes. A saliva sample was also provided for assay of basal testosterone. Results showed no compelling evidence that basal testosterone correlates with gender-stereotyped personality attributes or explains the relationship between sex/gender identity and these attributes, across, within, or covarying out sex assigned at birth. Contributing to a more gender diverse approach to assessing sex/gender relationships with personality and testosterone, our continuous measure of self-perceived masculinity and femininity predicted additional variance in personality beyond binary sex and showed some preliminary but weak relationships with testosterone. Results from this study cast doubt on the activational testosterone-masculinity hypothesis for explaining sex differences in gender stereotyped traits and within-sex/gender variation in attributes associated with agency and communality.

Persistent gender differences in spatial ability, even in STEM experts

Background

Spatial ability (SA) shows wide variability. One proposed explanation for the observed individual difference in SA is variability in interest and engagement in activities that promote spatial ability. Research also robustly shown that males on average outperform females in most aspects of SA. Previous studies have identified a number of activities that can potentially contribute to both individual and gender differences in SA, including tinkering with electronics, particular sports activities, and designing. However, the findings regarding these links are inconsistent. One way to investigate these links is to compare the groups that are intensively engaged with these activities.

Aim

The present study aims to evaluate the robustness of these links by comparing SA in adolescents with expertise in STEM, arts, and sports, with their unselected peers. We also aimed to assess whether gender differences in SA are still present in expert groups.

Methods

The data on ten small-scale SA tests was collected in an unselected sample of adolescents (N = 864, Mean age = 15.4, SD = 1.1); as well as in 3 samples of adolescents with expertise in STEM (N = 667, Mean age = 15, SD = 1.2); in Arts (N = 280, Mean age = 15, SD = 1.2) and in Sports (N = 444, Mean age = 14.3, SD = 0.7).

Results

Out of the three expert groups, only STEM experts on average outperformed the unselected group on all SA tasks. The STEM experts also outperformed Arts and Sports experts. Gender differences persisted in all expert groups, with moderate effect sizes.

Discussion

Findings support previously established links between spatial ability and STEM-related expertise. In contrast, such links were not found for expertise in arts and sports. Consistent with previous research, we found gender differences in SA for all samples, which persisted in STEM experts.

No evidence of a positive effect of learning Chinese language as an L2 on spatial ability

Spatial ability (SA) was shown to be a robust predictor of success in various educational contexts, including STEM. Thus, ways to improve SA are of interest to educational psychology. There is some evidence that SA might be improved via learning character-based language, e.g. Chinese as a second language (CSL), however, the existing research is quite limited. The study aims to investigate an effect of CSL learning on SA in schoolchildren from Year 2 to Year 7. Current study employs a sample of Russian schoolchildren (N = 283), who learnt: English only, English and Spanish; or English and Chinese. Participants completed Raven's progressive matrices and Mental rotation task at the age of 8 and again at the age of 14. Our data showed negligible group differences in the initial SA level at Year 2 (before learning second language). Similar negligible differences were found at Year 7. Regression analysis showed that SA was predicted by intelligence (Raven's) and gender but not language learnt at both ages. This pattern of results indicates that learning a Chinese as a second language is unlikely to affect SA. Further research is needed to investigate whether other factors, such as length, intensity and context of learning, moderate this link.

Spatial anxiety and self-confidence mediate sex/gender differences in mental rotation

A recent meta-synthesis study with a sample of >12 million participants revealed that the male advantage in mental rotation (MR) is the largest cognitive sex/gender difference found in psychological literature. MR requires test takers to mentally rotate three-dimensional cubic figures under time restrictions. Previous studies have investigated how biological and social factors contribute to cognitive sex/gender differences in tasks of this type. Spatial anxiety and self-confidence in MR tasks have received less attention. The present study investigated the contribution of these psychological factors to sex/gender differences in MR performance. Participants (n = 269) completed two MR tasks that differed in task difficulty. Participants also indicated their self-confidence (for each item) and spatial anxiety. The results revealed that pronounced sex/gender differences in spatial anxiety and self-confidence mediate sex/gender in MR performance, especially when task demands are high. The current findings suggest that task-irrelevant factors that are not spatial cognitive in nature contribute largely to the well-known medium to large sex/gender differences in MR. Future studies should further explore mechanisms underlying cognitive sex/gender differences within a biopsychosocial approach.

Measuring Spatial Ability for Talent Identification, Educational Assessment, and Support: Evidence from Adolescents with High Achievement in Science, Arts, and Sports

Background

Spatial ability (SA) is a robust predictor of academic and occupational achievement. The present study investigated the psychometric properties of 10 tests for measuring of SA in a sample of talented schoolchildren.

Objective

Our purpose was to identify the most suitable measurements for SA for the purpose of talent identification, educational assessment, and support.

Design

Our sample consisted of 1479 schoolchildren who had demonstrated high achievement in Science, Arts, or Sports. Several criteria were applied to evaluate the measurements, including an absence of floor and ceiling effects, low redundancy, high reliability, and external validity.

Results

Based on these criteria, we included the following four tests in an Online Short Spatial Ability Battery "OSSAB": Pattern Assembly; Mechanical Reasoning; Paper Folding; and Shape Rotation. Further analysis found differences in spatial ability across the three groups of gifted adolescents. The Science track showed the highest results in all four tests.

Conclusion

Overall, the study suggested that the Online Short Spatial Ability Battery (OSSAB) can be used for talent identification, educational assessment, and support. The analysis showed a unifactorial structure of spatial abilities. Future research is needed to evaluate the use of this battery with other specific samples and unselected populations.

Psychoneuroendocrine protocol to comprehensively study sexually dimorphic cognition

Background

A large body of research provides evidence for sex differences in cognitive abilities. These sex differences stem from the interplay between biological sex (e.g., birth-assigned sex, sex hormones) and psychosocial gender (e.g., gender identity, gender-roles, sexual orientation). Literature remains rather mixed with regards to the magnitude of sex and gender effects on cognitive abilities and mental health. Growing evidence shows that sex hormone assessment combined with measures of psychosocial gender may be fundamental to comprehensively understand individual differences in sexually dimorphic cognitive abilities.

Objectives

This study protocol describes a sexually dimorphic cognitive battery to assess the influence of sex hormones on performance. In parallel, we aim to assess the inter-related effects that biological sex and psychosocial gender-based factors exert on cognition and mental health.

Methods

Our projected sample includes 180 adult participants who are at least 18 years old. Sub-groups will be recruited based on birth-assigned sex, gender identity, and sexual orientation. Biological measures will be collected via salivary samples throughout testing to include sex hormones (testosterone, estradiol and progesterone) and stress hormones (cortisol). Demographic and psychosocial variables will be measured through self-report questionnaires. Participants will be required to complete eight classic cognitive tasks that assess a variety of cognitive domains in a 2-h testing session.

Results and future directions

Results from this study provides unique insights into the correlates of cognitive sex differences and gender diversity. This will give us solid ground to further investigate these influences in clinical populations in which sex hormones and cognitive functioning are often altered.

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Cognition is modulated by multiple sex and gender factors.

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Cognitive abilities will be assessed among 180 adults representing diverse sexual orientations and gender identities.

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This protocol aims to nuance the effects of sex hormones in contrast to those of socio-cultural gender.

Gender differences in mothers' spatial language use and children's mental rotation abilities in Preschool and Kindergarten

Mental rotation has emerged as an important predictor of success in Science, Technology, Engineering, and Math (STEM). By the age of 4.5 years, boys outperform girls in these abilities. Because parents use less spatial language with girls at this age (Pruden and Levine, 2017), the amount of spatial language that children are exposed to at home is believed to be one potential contributor to this disparity in preschool age children. To date, it is unclear if this gender difference continues when children enter school. To address this question in this study, children not yet in kindergarten (PreK) and kindergarten and first grade children (K+) were recorded playing with their mothers using magnetic tile toys followed by children's completion of a mental rotation task. As expected, mothers used more spatial language with PreK boys than girls; however, this relationship reversed in K+, with mothers using significantly more spatial language with girls than boys. Surprisingly, despite this, boys outperformed girls on the mental rotation task. These findings suggest that although girls' exposure to spatial language is higher after entry into school, this language difference is not reflected in increases in mental rotation abilities. Thus, earlier exposure to spatial language may be vital for the development of mental rotation abilities.

Evidence for a unitary structure of spatial cognition beyond general intelligence

Performance in everyday spatial orientation tasks (e.g., map reading and navigation) has been considered functionally separate from performance on more abstract object-based spatial abilities (e.g., mental rotation and visualization). However, few studies have examined the link between spatial orientation and object-based spatial skills, and even fewer have done so including a wide range of spatial tests. To examine this issue and more generally to test the structure of spatial ability, we used a novel gamified battery to assess six tests of spatial orientation in a virtual environment and examined their association with ten object-based spatial tests, as well as their links to general cognitive ability (g). We further estimated the role of genetic and environmental factors in underlying variation and covariation in these spatial tests. Participants (N = 2660; aged 19-22) were part of the Twins Early Development Study. The six tests of spatial orientation clustered into a single 'Navigation' factor that was 64% heritable. Examining the structure of spatial ability across all 16 tests, three, substantially correlated, factors emerged: Navigation, Object Manipulation, and Visualization. These, in turn, loaded strongly onto a general factor of Spatial Ability, which was highly heritable (84%). A large portion (45%) of this high heritability was independent of g. The results point towards the existence of a common genetic network that supports all spatial abilities.

Morphometric traits predict educational attainment independently of socioeconomic background

Background

Aim of this study is to describe the relationship between anthropometric traits and educational attainment among Estonian schoolchildren born between 1937 and 1962. We asked whether height, cranial volume and face width (a testosterone-dependent trait), measured in childhood predict later educational attainment independently of each other, family socioeconomic position (SEP) and sex. Associations between morphometric traits and education and their interactions with biosocial variables are of scholarly importance because higher education is nearly universally associated with low fertility in women, and often with high fertility in men. Hence, morphometric traits associated with educational attainment are targeted by natural selection and describing the exact nature of these associations is relevant for understanding the current patterns of evolution of human body size.

Methods

Data on morphometric measurements and family background of 11,032 Estonian schoolchildren measured between seven and 19 years of age were obtained from the study performed by Juhan Aul between 1956 and 1969. Ordinal logistic regression was used for testing the effects of morphometric traits, biosocial variables and their interaction on the cumulative probability of obtaining education beyond primary level.

Results

Of biosocial variables, family SEP was the most important determinant of educational attainment, followed by the sex, rural vs urban origin and the number of siblings. No significant interactions with morphometric traits were detected, i.e., within each category of SEP, rural vs urban origin and sex, taller children and those with larger heads and relatively narrower faces were more likely to proceed to secondary and/or tertiary education. The effect of height on education was independent of cranial volume, indicating that taller children did not obtain more educations because their brains were larger than those of shorter children; height per se was important.

Conclusions

Our main finding – that adjusting for other morphometric traits and biosocial variables, morphometric traits still robustly predicted educational attainment, is relevant for understanding the current patterns of evolution of human body size. Our findings suggest that fecundity selection acting on educational attainment could be partly responsible for the concurrent selection for smaller stature and cranial volume in women and opposite trends in men.