Sex Differences In Cognitive Abilities Research Articles

Verbal Abilities: Sex Differences in Children at Different Ages.

The assertion of sex differences in verbal abilities is a highly controversial subject. Some studies have demonstrated a female advantage; other studies have found higher rates in males. The results depended on the type of verbal ability that was studied, the cultural context, and the ages of the subjects. There are two types of theories that have been developed to explain the existence of sex differences in cognitive abilities. Social theories explain the differences as caused by social determinants. Biological theories consider biological factors such as prenatal development conditions and hormone levels, among others, as the cause of sex differences. To investigate sex differences in verbal abilities in children of different ages. Two different editions of Wechsler tests were used. For children age 2.5 to 5 years, the Wechsler Preschool Primary Scale of Intelligence (WPPSI-IV) was used. For children age 6 and older, we administered the Wechsler Intelligence Scale for Children (WISC-V). The total sample included 313 children. The study found significant sex differences in performance on the Verbal Comprehension Scale in children of different ages. At the age of 2 to 4 years, the girls performed better than the boys. In the group of boys, there was a significant increase in verbal abilities at the age of 8-9 years. By the age of 10-11 years, boys began outperforming girls on the Verbal Comprehension Index. Scores on the Verbal Comprehension and Visual Spatial subtests for the boy sample showed stronger correlations than in the girl sample in all age groups. Sex differences in verbal abilities varied depending on the age of the children. The boys showed a stronger integration of their verbal abilities into the structure of their intelligence than the girls.

Sex differences in the cognitive abilities of a sex-changing fish species Labroides dimidiatus.

Males and females of the same species are known to differ at least in some cognitive domains, but such differences are not systematic across species. As a consequence, it remains unclear whether reported differences generally reflect adaptive adjustments to diverging selective pressures, or whether differences are mere side products of physiological differences necessary for reproduction. Here, we show that sex differences in cognition occur even in a sex-changing species, a protogynous hermaphroditic species where all males have previously been females. We tested male and female cleaner fish Labroides dimidiatus in four cognitive tasks to evaluate their learning and inhibitory control abilities first in an abstract presentation of the tasks, then in more ecologically relevant contexts. The results showed that males were better learners than females in the two learning tasks (i.e. reversal learning as an abstract task and a food quantity assessment task as an ecologically relevant task). Conversely, females showed enhanced abilities compared with males in the abstract inhibitory control task (i.e. detour task); but both sexes performed equally in the ecologically relevant inhibitory control task (i.e. ‘audience effect’ task). Hence, sex-changing species may offer unique opportunities to study proximate and/or ultimate causes underlying sex differences in cognitive abilities.

Autism spectrum disorder: An examination of sex differences in neuropsychological and self-report measures of executive and non-executive cognitive function.

Research comparing females and males with a diagnosis of autism suggests that there are sex differences in some characteristics such as behaviour regulation. One area not studied in detail is whether females and males with autism perform differently in tests of cognitive ability. The results of previous research are quite mixed. One explanation may be that some research comparing females and males with autism did not include a neurotypical control group for comparison. As a result, it is not clear whether the sex differences in cognitive ability observed in people with autism are similar to differences between neurotypical males and females. To better understand whether there are unique differences between males and females with autism, it is important to also compare them with neurotypical males and females. In our research, we included a neurotypical group and compared males and females with and without a diagnosis of autism. We found that the sex differences in autism are similar to what we observe in males and females without autism. Our study showed that compared with males, females (with and without autism) do better in assessments of processing speed, cognitive flexibility, verbal learning and memory and semantic fluency. Our results suggest that although females show different cognitive performance to males, these sex differences were not specific to the group with a diagnosis of autism.

Psychoneuroendocrine protocol to comprehensively study sexually dimorphic cognition

BackgroundA 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. ObjectivesThis 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. MethodsOur 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 directionsResults 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.

Sex Differences in Korsakoff's Syndrome for Inhibition but Not for Episodic Memory or Flexibility.

While sex differences in cognitive abilities have been extensively studied in healthy populations, little is known about these differences in patients with Korsakoff syndrome (KS). We investigated sex differences in verbal episodic memory, inhibition, and flexibility in 25 patients with KS and 25 control participants. The analysis demonstrated no significant differences between women with KS and men with KS on episodic memory and flexibility, but higher inhibition was observed in women with KS compared with men with KS. Regarding control participants, no significant differences were observed between women and men on inhibition or flexibility, but higher verbal episodic memory was observed in women compared with men. Verbal episodic memory and flexibility seem to be equally affected in women and men with KS, whereas inhibition seems to be more affected in men than in women with KS. Our findings highlight cognitive sex differences in KS in executive function. Critically, our findings are the first quantitative data about episodic performances (and cognitive performances in general) of women and men with KS. (Am J Addict 2020;29:129-133).

Sex differences in cognition and their relationship to male mate choice

Male cognition has gained recognition as an important potential player in sexual selection. A number of studies have found positive correlations between male sexual signals and cognitive performance and/or female preferences for males with better cognitive performance, although other studies have not found these relationships. Sex roles can differ dramatically, and sex differences in selection on cognition likely follow from the different tasks associated with these sex roles. Here, using threespine stickleback Gasterosteus aculeatus, a species with clearly divergent sex roles and mutual mate choice, we focus on the cognitive trait inhibitory control because males must differentially respond to reproductive females versus other sticklebacks while defending territories and refrain from eating eggs and fry while performing paternal care. We presented fish with a detour task four times over a period of 7 days, allowing us to assess initial inhibitory control and improvement over time. We ask 1) whether there are sex differences in inhibitory control and 2) whether male mate choice is associated with female inhibitory control. Although males outperformed females on three different measures of detour task performance across four trials, these differences were largely explained by males being less neophobic than females. Females took more trials to successfully solve the detour task, even after accounting for sex differences in neophobia. Female cognitive abilities, however, were unrelated to the vigor with which males courted them. The equivocal results regarding sex differences in cognitive ability suggest further study given the very different selection pressures each sex experiences.

No Sex Differences in Cognitive Ability in Young Children with Autism Spectrum Disorder.

Inconsistent findings regarding sex differences in cognition have been found in people with autism spectrum disorder (ASD). This study evaluated sex differences in cognitive-developmental functioning in a large clinical sample of young children diagnosed with ASD. The sample included children 18-68 months of age who received the Mullen Scales of Early Learning (MSEL) through Autism Treatment Network (ATN) sites from 2007 to 2013 (N = 1587, 16.7% female). In this large clinically referred sample of young children with ASD in the United States, no significant differences were found between the sexes for the MSEL Early Learning Composite (ELC) standard score, domain T Scores or age equivalents. These findings persisted when examining different age ranges, cognitive levels and domain profiles.

Sex-specific contribution of DHEA-cortisol ratio to prefrontal-hippocampal structural development, cognitive abilities and personality traits.

Although dehydroepiandrosterone (DHEA) may exert neuroprotective effects in the developing brain, prolonged or excessive elevations in cortisol may exert neurotoxic effects. The ratio between DHEA and cortisol (DC ratio) has been linked to internalising and externalising disorders, as well as cognitive performance, supporting the clinical relevance of this hormonal ratio during development. However, the brain mechanisms by which these effects may be mediated have not yet been identified. Furthermore, although there is evidence that the effects of cortisol in the central nervous system may be sexually dimorphic in humans, the opposite is true for DHEA, with human studies showing no sex-specific associations in cortical thickness, cortico-amygdalar or cortico-hippocampal structural covariance. Therefore, it remains unclear whether sex moderates the developmental associations between DC ratio, brain structure, cognition and behaviour. In the present study, we examined the associations between DC ratio, structural covariance of the hippocampus with whole-brain cortical thickness, and measures of personality, behaviour and cognition in a longitudinal sample of typically developing children, adolescents and young adults aged 6-22years (N=225 participants [F=128]; 355 scans [F=208]), using mixed effects models that accounted for both within- and between-subject variances. We found sex-specific interactions between DC ratio and anterior cingulate cortex-hippocampal structural covariance, with higher DC ratios being associated with a more negative covariance between these structures in girls, and a more positive covariance in boys. Furthermore, the negative prefrontal-hippocampal structural covariance found in girls was associated with higher verbal memory and mathematical ability, whereas the positive covariance found in boys was associated with lower cooperativeness and reward dependence personality traits. These findings support the notion that the ratio between DHEA and cortisol levels may contribute, at least in part, to the development of sex differences in cognitive abilities, as well as risk for internalising/externalising disorders, via an alteration in prefrontal-hippocampal structure during the transition from childhood to adulthood.

Cognitive abilities in women with complete androgen insensitivity syndrome and women with gonadal dysgenesis

BackgroundMany questions regarding the mechanisms behind sex differences in cognitive abilities are still unanswered. On a group level, men typically outperform women on certain spatial tasks, whereas women perform better on certain tests of memory and verbal ability. The prevailing theories concerning the biological predispositions for these and other differences in behaviour and brain function focus on early and prolonged exposure to sex hormones. There is, however, evidence of direct effects of sex chromosomes on sex-typical behaviour in other species. ObjectivesTo study the influence of sex hormones and sex chromosomes on cognition in women with Complete androgen insensitivity (CAIS) and Gonadal dysgenesis (GD). MethodsEighteen women with CAIS, 6 women with 46,XYGD, and 7 women with 46,XXGD were compared with age-matched male and female controls on tests of spatial and verbal abilities, memory functions, and emotion recognition. ResultsWomen with CAIS, XYGD, and XXGD performed similar to female controls on cognitive tasks. However, on a test of emotion recognition, women with XXGD outperformed the other groups, whereas women with CAIS and XYGD performed similar to male controls. ConclusionOur results support theories of androgen effects on cognitive abilities and suggest that factors related to sex chromosomes may influence emotion recognition. Implications of an atypical sex hormone situation and sex chromosome variation are discussed.

Sex differences in cognitive abilities: Analyses for the German WAIS-IV

Sex differences on 15 subtests, the four indices, and the full scale IQ of the Wechsler Adult Intelligence Scale - Fourth Edition (WAIS-IV) are examined in the total national standardization sample (N=944 males, 924 females) of the WAIS-IV. This sample, whose ages range from 16 to 89years, were chosen by a stratified, random-sampling procedure to be representative of the population of Germany according to demographic features revealed in the 2012 census. Women scored lower in all indices and subtests with the exception of the Processing Speed Index (PSI) and the associated subtests, whereby the differences in means range between 3.2 and 4.9 IQ-points at the index level (FSIQ: Difference=3.2, WMI: Difference=4.9). But the maximum effect size of sex tends to be smaller (η2=0.050) than the minimum effect size of education level (ranges from ω2=0.055 to ω2=0.289). It must be noted that the participants' education background, as defined by the highest attained education level, exerted a much greater effect upon cognitive abilities than sex did. A psychobiosocial model with the aim of accounting for sex-related differences in intelligence should be discussed.

Sex Differences and Menstrual Cycle Dependent Changes in Cognitive Strategies during Spatial Navigation and Verbal Fluency.

Men typically outperform women in spatial navigation tasks, while the advantage of women in verbal fluency is more controversial. Sex differences in cognitive abilities have been related to sex-specific cognitive strategies on the one hand and sex hormone influences on the other hand. However, sex hormone and menstrual cycle influences on cognitive strategies have not been previously investigated. In the present study we assessed cognitive strategy use during spatial navigation and verbal fluency in 51 men and 49 women. In order to evaluate sex hormone influences, all participants completed two test sessions, which were time-locked to the early follicular (low estradiol and progesterone) and mid-luteal cycle phase (high estradiol and progesterone) in women. As hypothesized, men outperformed women in navigation, whereas women outperformed men in phonemic verbal fluency. Furthermore, women switched more often between categories in the phonemic fluency condition, compared to men, indicating sex-specific strategy use. Sex differences in strategy use during navigation did, however, not follow the expected pattern. Menstrual cycle phase, however, did modulate strategy use during navigation as expected, with improved performance with the landmark strategy in the luteal, compared to the follicular phase. No menstrual cycle effects were observed on clustering or switching during verbal fluency. This suggests a modulation of cognitive strategy use during spatial navigation, but not during verbal fluency, by relative hormone increases during the luteal phase of the menstrual cycle.

Testing Lynn’s Theory of Sex Differences in Intelligence in a Large Sample of Nigerian School-Aged Children and Adolescents (N>11,000) using Raven’s Standard Progressive Matrices Plus

Sex differences in intelligence have been much disputed for many decades. The present study examined the issues of whether sex differences in intelligence change during development. In total, 11,164 children (mean age = 13.5 years; SD = 2.6 years) completed the Standard Progressive Matrices Plus (SPM+). From age 8 to 19 years, sex differences in the total score of the SPM+ increased from -0.06d (favoring females) to 0.46d (favoring males), with an average of 0.23d. Our findings support Lynn’s developmental theory of sex differences in cognitive abilities.

Cognitive Sex Differences: Evolution and History

We add results from studies in Germany and Brazil supporting Lynn’s theory on cognitive sex differences and their development. We show that there are associations between hormonal transitions during adolescence, especially in women, and increasing sex differences in cognitive abilities, particularly spatial ability, during adolescence. We suggest that such maturation-related changes make sense from an evolutionary perspective, as cognitive and ecological specializations of the sexes, with the benefit of increasing group fitness due to differentiation of social gender roles. However, historical and cultural change has reduced male-favoring gender differences in education and in many cases reversed them. Together with changes in the job market this has modified formerly stable sex differences.

Male and female guppies differ in speed but not in accuracy in visual discrimination learning.

In many species, males and females have different reproductive roles and/or differ in their ecological niche. Since in these cases the two sexes often face different cognitive challenges, selection may promote some degree of cognitive differentiation, an issue that has received relatively little attention so far. We investigated the existence of sex differences in visual discrimination learning in the guppy, Poecilia reticulata, a fish species in which females show complex mate choice based on male colour pattern. We tested males and females for their ability to learn a discrimination between two different shapes (experiment 1) and between two identical figures with a different orientation (experiment 2). In experiment 3, guppies were required to select an object of the odd colour in a group of five objects. Colours changed daily, and therefore, the solution for this task was facilitated by concept learning. We found males' and females' accuracy practically overlapped in the three experiments, suggesting that the two sexes have similar discrimination learning abilities. Yet, males showed faster decision time than females without any evident speed-accuracy trade-off. This result indicates the existence of consistent between-sex differences in decision speed perhaps due to impulsivity rather than speed in information processing. Our results align with previous literature, indicating that sex differences in cognitive abilities are the exception rather than the rule, while sex differences in cognitive style, i.e. the way in which an individual faces a cognitive task, are much more common.

Sex and sex-role differences in specific cognitive abilities

Sex differences in cognitive abilities are a controversial but actively researched topic. The present study examined whether sex-role identity mediates the relationship between sex and sex-typed cognitive abilities. Three hundred nine participants (105 males and 204 females) were tested on a range of visuospatial and language tasks under laboratory conditions. Participants also completed measures of sex-role identity, used to classify them into masculine, feminine, androgynous and undifferentiated groups. While sex differences were found for some but not all measures, significant sex-role differences were found for all spatial and language measures with the exception of a novel 2D Mental Rotation Task. Masculine sex-roles partially mediated the relationship between sex and a composite measure of spatial ability, while feminine sex-roles fully mediated the relationship between sex and a composite measure of language ability. These results suggest that sex-role identity may have greater utility in explaining individual differences in cognitive performance than biological sex alone.

Cognitive function in women with polycystic ovary syndrome (PCOS): impact of reproductive and metabolic factors

Cognitive function in women with polycystic ovary syndrome (PCOS): impact of reproductive and metabolic factors

The effects of acute alcohol on psychomotor, set-shifting, and working memory performance in older men and women

A limited number of publications have documented the effects of acute alcohol administration among older adults. Among these, only a few have investigated sex differences within this population. The current project examined the behavioral effects of acute low- and moderate-dose alcohol on 62 older (ages 55–70) male and female, healthy, light to moderate drinkers. Participants were randomly assigned to one of three dose conditions: placebo (peak breath alcohol concentration [BrAC] of 0 mg/dL), low (peak BrAC of 40 mg/dL), and moderate (peak BrAC of 65 mg/dL). Tasks assessed psychomotor, set-shifting, and working memory performance. Better set-shifting abilities were observed among women, whereas men demonstrated more efficient working memory, regardless of dose. The moderate-dose group did not significantly differ from the placebo group on any task. However, the low-dose group performed better than the moderate-dose group across measures of set shifting and working memory. Relative to the placebo group, the low-dose group exhibited better working memory, specifically for faces. Interestingly, there were no sex by dose interactions. These data suggest that, at least for our study's task demands, low and moderate doses of alcohol do not significantly hinder psychomotor, set-shifting, or working memory performance among older adults. In fact, low-dose alcohol may facilitate certain cognitive abilities. Furthermore, although sex differences in cognitive abilities were observed, these alcohol doses did not differentially affect men and women. Further investigation is necessary to better characterize the effects of sex and alcohol dose on cognition in older adults.

Sex Differences in Fluid Reasoning: Manifest and Latent Estimates from the Cognitive Abilities Test

The size and nature of sex differences in cognitive ability continues to be a source of controversy. Conflicting findings result from the selection of measures, samples, and methods used to estimate sex differences. Existing sex differences work on the Cognitive Abilities Test (CogAT) has analyzed manifest variables, leaving open questions about sex differences in latent narrow cognitive abilities and the underlying broad ability of fluid reasoning (Gf). This study attempted to address these questions. A confirmatory bifactor model was used to estimate Gf and three residual narrow ability factors (verbal, quantitative, and figural). We found that latent mean differences were larger than manifest estimates for all three narrow abilities. However, mean differences in Gf were trivial, consistent with previous research. In estimating group variances, the Gf factor showed substantially greater male variability (around 20% greater). The narrow abilities varied: verbal reasoning showed small variability differences while quantitative and figural showed substantial differences in variance (up to 60% greater). These results add precision and nuance to the study of the variability and masking hypothesis.

Sex differences in reasoning abilities: Surprising evidence that male–female ratios in the tails of the quantitative reasoning distribution have increased

Sex differences in cognitive abilities, particularly at the extremes of ability distributions, have important implications for the participation of men and women in highly valued and technical career fields. Although negligible mean differences have been found in many domains, differences in variability and high ratios of males to females in the tails of the ability distribution have been found in a number of studies and across domains. A few studies have also observed trends over time, with some noting the decreasing ratios of boys to girls in the highest levels of mathematics test performance. In this study, sex differences in means, variances, and ratios were evaluated in four cohorts (1984, 1992, 2000, and 2011) in verbal, quantitative, and nonverbal/figural reasoning domains as measured by the Cognitive Abilities Test. Samples included US students in grades 3–11. Overall, the results were consistent with previous research, showing small mean differences in the three domains, but considerably greater variability for males. The most surprising finding was that, contrary to related research, the ratio of males to females in the upper tail of the quantitative reasoning distribution seemed to increase over time. Explanations for this finding are explored.

Studying Intellectual Outliers

By studying samples of intellectual outliers across 30 years, researchers can leverage right-tail data (i.e., samples at or above the 95th percentile on tests of ability) to uncover missing pieces to two psychological puzzles: whether there are sex differences in cognitive abilities among smart people, and whether test scores are rising (a phenomenon known as the Flynn effect) among smart people. For the first puzzle, data indicate that the high male-to-female ratio among extremely high scorers on measures of math ability has decreased dramatically, but is still likely one factor among many explaining female underrepresentation in some professions. For the second puzzle, data indicate that the right tail has risen at a similar rate as the general (or middle portion of the) distribution; it is thus likely that the entire curve is rising at a relatively constant rate, consistent with the Flynn effect, which may explain why a greater number of gifted students have been identified in recent years. However, the causes for these gains and whether they reflect real gains in intelligence continue to remain a mystery. We show how these two puzzles are linked and stress the importance of paying attention to the entire distribution when attempting to address some scientific questions.