Sex Differences In Means Research Articles

Development of a latent dementia index in the aging, demographics, and memory study: Validation and measurement invariance by sex.

Latent variable models can create a latent dementia index (LDI) using cognitive and functional ability to approximate dementia likelihood. The LDI approach has been applied across diverse cohorts. It is unclear whether sex affects its measurement properties. We use Wave A (2001-2003) of the Aging, Demographics, and Memory Study (n=856). Multiple group confirmatory factor analysis (CFA) was used to test measurement invariance (MI) using informant-reported functional ability and cognitive performance tasks, which we group into verbal, nonverbal, and memory. Partial scalar invariance was found, allowing for testing sex differences in LDI means (MDiff=0.38). The LDI correlated with consensus panel dementia diagnosis, Mini-Mental State Examination (MMSE), and dementia risk factors (low education, advanced age, and apolipoprotein ε4 [APOE-ε4] status) for men and women. The LDI validly captures dementia likelihood to permit estimation of sex differences. LDI sex differences indicate higher dementia likelihood in women, potentially due to social, environmental, and biological factors.

Beyond Simple Mean Differences: Analysis of Sex Similarities and Differences in Academic Achievement With the Kaufman Tests of Educational Achievement, Third Edition

Simple mean differences summarized in meta-analyses do not always adequately describe sex similarities and differences. We investigated sex similarities and differences in academic achievement test scores during childhood and adolescence multiple ways based on composite and subtest scores from the Kaufman Test of Educational Achievement (Third edition) norming sample. Sex differences in means were investigated across achievement domains and ability levels. Test score variance and percentages of scores at different parts of score distributions were also compared across sex. The largest and most consistent sex differences were female advantages in writing tests: Larger advantages were found in more complex writing tasks. Females also showed consistent advantages in silent reading fluency. Males demonstrated advantages in math problem solving that emerged at the average ability level. Females were more likely to be high achievers in reading fluency and written expression, whereas males were more likely to be low achievers in reading fluency and aspects of writing, and very low achievers in word recognition, word recognition fluency, and reading vocabulary. Males were more likely to be high achievers in math problem solving. Analysis that goes beyond simple mean differences reveals important sex differences regarding academic achievement, and theories should account for overall patterns of academic achievement similarities and differences.

Prevalence of adverse childhood experiences among Vietnamese high school students

BackgroundAdverse childhood experiences (ACE) are linked to a range of negative health outcomes. However, the majority of research has been conducted in high-income-countries and little is known about ACE prevalence in low-and-middle-income-countries (LMIC), where the majority of the world's youth reside. ObjectiveAssess ACE prevalence and demographic correlates in two provinces of the Southeast Asian LMIC Vietnam. MethodsPrevalence of ACE were assessed among 644 Vietnamese high-school students, using the WHO Adverse Childhood Experiences-International Questionnaire. ResultsAbout 74% of participants reported experiencing at least one ACE, with 27% reporting experiencing three or more ACE. Prevalence of sexual abuse was above 10% for both males and females. Sex differences were non-significant, suggesting child protective services should give consideration to both males and females. Factor analysis identified two patterns of ACE: Violence and Aggression in Family and Community, and Family Member Dysfunction. Three ACE (sexual abuse, emotional neglect, physical neglect) did not load on either factor. Thus, at least in our sample, sexual abuse was independent of other ACE, which indicates that it can occur in any context, among children in otherwise well-functioning families, an important consideration for child protective services. The lack of significant sex differences in sexual abuse means that Vietnamese boys need equal consideration for protection and support as girls. ConclusionsResults indicate that ACE are a prevalent public health problem in Vietnam. Future research evaluating potential ACE risk factors such as authoritarian parenting may be useful to identify possible targets for prevention programs in Vietnam.

A meta-analysis of sex differences in animal personality: no evidence for the greater male variability hypothesis.

The notion that men are more variable than women has become embedded into scientific thinking. For mental traits like personality, greater male variability has been partly attributed to biology, underpinned by claims that there is generally greater variation among males than females in non-human animals due to stronger sexual selection on males. However, evidence for greater male variability is limited to morphological traits, and there is little information regarding sex differences in personality-like behaviours for non-human animals. Here, we meta-analysed sex differences in means and variances for over 2100 effects (204 studies) from 220 species (covering five broad taxonomic groups) across five personality traits: boldness, aggression, activity, sociality and exploration. We also tested if sexual size dimorphism, a proxy for sex-specific sexual selection, explains variation in the magnitude of sex differences in personality. We found no significant differences in personality between the sexes. In addition, sexual size dimorphism did not explain variation in the magnitude of the observed sex differences in the mean or variance in personality for any taxonomic group. In sum, we find no evidence for widespread sex differences in variability in non-human animal personality.

Sex Differences in Means and Variance of Intelligence among Middle School Children in the Rural Commune Sidi El Kamel (North-Western Morocco)

Sex Differences in Means and Variance of Intelligence among Middle School Children in the Rural Commune Sidi El Kamel (North-Western Morocco)

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.

Inheritance of dermatoglyphic traits in twins: Univariate and bivariate variance decomposition analysis

Dermatoglyphic traits in a sample of twins were analyzed to estimate the resemblance between MZ and DZ twins and to evaluate the mode of inheritance by using the maximum likelihood-based Variance decomposition analysis. The additive genetic variance component was significant in both sexes for four traits--PII, AB_RC, RC_HB, and ATD_L. AB RC and RC_HB had significant sex differences in means, whereas PII and ATD_L did not. The results of the Bivariate Variance decomposition analysis revealed that PII and RC_HB have a significant correlation in both genetic and residual components. Significant correlation in the additive genetic variance between AB_RC and ATD_L was observed. The same analysis only for the females sub-sample in the three traits RBL, RBR and AB_DIS shows that the additive genetic RBR component was significant and the AB_DIS sibling component was not significant while others cannot be constrained to zero. The additive variance for AB DIS sibling component was not significant. The three components additive, sibling and residual were significantly correlated between each pair of traits revealed by the Bivariate Variance decomposition analysis.

Sex Differences in Means and Variance of Intelligence: Some data for Spain

It has been very widely asserted that there is no sex difference in average general intelligence but that males have greater variability than females. We examine these propositions in a sample of 258 adults tested with the Progressive Matrices in Spain and find that both of them are incorrect.

Sex Differences in Means and Variance of Intelligence: Some data from Morocco

The study provides the first report for intelligence in Morocco and gives data for a sample of 202 adults tested with the Raven Standard Progressive Matrices. The results show that in this sample, men had a higher mean IQ than women by 5.7 IQ points. Sex differences in variance

Norms and Gender Differences on the Progressive Matrices in Sudan

A standardization of the Progressive Matrices in Sudan for the ages 9 through 25 years is analysed for sex differences in means and variability. There are no sex differences in means at the ages 9, 11, 12, 13 and 19 years. At age 14 through 18 years females obtain higher means than males, while at ages 10 and 20-25 years males obtain higher means than females. There are no consistent sex differences in variability.

Genetic and Environmental Influences on Type A Behavior Pattern: Evidence From Twins and Their Parents in The Netherlands Twin Register

There is a dose-response positive relationship between type A behavior (TABP) and cardiovascular disease-related symptoms. Estimates of heritability for TABP from previous studies vary; this might be explained by limitations in the sizes and compositions of the samples. This study combines a large sample size, twin and parental, data from males and females, two generations of young adults and older adults, and the use of structural equation modeling (SEM) and full information maximum likelihood (FIML) estimation. To assess TABP, the Jenkins Activity Survey (JAS) was collected from MZ and DZ twins and their parents (n = 1670 twin families). Structural equation modeling is used to evaluate and estimate the effects of additive and nonadditive genetic effects, nonshared environmental effects, and competitive sibling interaction. Forty-five percent of the variance in TABP was the result of genetic factors (28% were additive and 17% were nonadditive). The remaining 55% of the variance was explained by environmental factors not shared by the members of the same family. Competitive sibling interaction effects were not significant. There was no evidence of sex differences either in variances or means. Understanding the sources of variance on TABP is important for therapy and prevention. According to the present results, the relevant environmental factors for the development of TABP are not shared by the members of the same family. The genetic portion of the variance is also worth considering for therapeutic purposes. Although the genetic code cannot be altered, its effects on behavior may be modifiable through the treatment of the biological mediators.

Genetic influences on fibrinogen, tissue plasminogen activatorantigen and von Willebrand factor in males and females

Differences in genetic influence on death from CHD between males and females have been reported. Haemostatic factors have consistently been associated with risk for coronary heart disease (CHD), but sex differences in genetic architecture have not been studied. This study in middle-aged twins investigates whether there are sex differences in means and in genetic and/or environmental variance components of haemostatic risk factors for CHD. A total of 93 monozygotic twin pairs (44 male and 49 female) and 116 dizygotic twin pairs (36 male, 40 female and 40 opposite sex) were available for this study. Structural equation modelling was used to estimate the relative influence of genetic and environmental factors on variation in levels of fibrinogen, tissue plasminogen activator (tPA) antigen and von Willebrand factor (vWF). Mean levels of tPA and vWF increased with age. Oral contraceptive pill (OCP) and menopause had significant influences on levels of fibrinogen and tPA. Genetic influences explained 39, 66 and 72% of the variation in levels of fibrinogen, tPA and vWF, respectively. No quantitative or qualitative differences of genetic influences on haemostatic levels were seen between males and females. Haemostatic factors may account for a significant part of the genetic risk for cardiovascular disease. No difference in genetic architecture for levels of fibrinogen, tPA or vWF was observed between males and females.

Multi-group covariance and mean structure modeling of the relationship between the WAIS-III common factors and sex and educational attainment in Spain

We investigated sex effects and the effects of educational attainment (EA) on the covariance structure of the WAIS-III in a subsample of the Spanish standardization data. We fitted both first order common factor models and second order common factor models. The latter include general intelligence ( g) as a second order common factor. The results indicate that sex differences in means are due mainly to the WAIS-III factors Working Memory (WM) and Perceptual Organization (PO), rather than to the second order g factor. In treating EA as a predictor of the first common factors, we found that EA explained a significant, but clearly varying, amount of variance in the 4 first order common factors. Differences in explained variance over sex were very small. Treating EA as a predictor in the second order common factor model, we found that EA predicted g and first order factor Verbal Comprehension (VC). The relationships between PO, WM, and Perceptual Speed (PS) and EA are mediated by g. In treating EA as a dependent variable, we found that VC and PS were the only significant predictors of EA in the first order common factor model. In the second order common factor model, the same result was obtained. While VC and PS were significant predictors of EA, the second order factor g, and PO and WM were not. The results are of theoretical interest in the light of the Ankney–Rushton paradox, and the role of g in educational attainment.

Sex differences in means and variability on the progressive matrices in university students: A meta‐analysis

A meta-analysis is presented of 22 studies of sex differences in university students of means and variances on the Progressive Matrices. The results disconfirm the frequent assertion that there is no sex difference in the mean but that males have greater variability. To the contrary, the results showed that males obtained a higher mean than females by between .22d and .33d, the equivalent of 3.3 and 5.0 IQ conventional points, respectively. In the 8 studies of the SPM for which standard deviations were available, females showed significantly greater variability (F(882,656) = 1.20, p < .02), whilst in the 10 studies of the APM there was no significant difference in variability (F(3344,5660) = 1.00, p > .05).

Investigating the Genetic and Environmental Structure of Cloninger's Personality Dimensions in Adolescence

In this study we examined the genetic and environmental structure of four dimensions from Cloninger's personality system: novelty-seeking (NS), harm-avoidance (HA), reward-dependence (RD), and persistence (PS). Although adult twin studies suggest that these personality dimensions are moderately heritable, this is the first twin study of Cloninger's personality dimensions in adolescence — a period marked by significant physiological and social changes. Study participants included 1851 adolescent twins between the ages of 11 and 18 years; 878 complete twin pairs and 95 singleton-responding twins. Subjects were participants in two community-based samples of twins residing in the state of Colorado. Results indicated that cross-sectional mean levels for NS, HA and RD tended to show modest increases across the adolescent years, while PS showed modest mean decreases. Consistent sex differences in means were found only for RD. Univariate biometrical twin models were used to decompose trait variance into genetic and environmental sources. Results indicated that for NS, HA and RD additive genetic influences and unique environmental effects were sufficient to explain the data. PS, however, could be explained by unique and common environmental effects only, with different patterns of common environmental effects for males and females. We found moderate heritability estimates for NS, HA and RD ranging from .28 to .36 — with no evidence for sex-limitation in those influences.

Investigating the Genetic and Environmental Structure of Cloninger's Personality Dimensions in Adolescence

In this study we examined the genetic and environmental structure of four dimensions from Cloninger's personality system: novelty-seeking (NS), harm-avoidance (HA), reward-dependence (RD), and persistence (PS). Although adult twin studies suggest that these personality dimensions are moderately heritable, this is the first twin study of Cloninger's personality dimensions in adolescence--a period marked by significant physiological and social changes. Study participants included 1851 adolescent twins between the ages of 11 and 18 years; 878 complete twin pairs and 95 singleton-responding twins. Subjects were participants in two community-based samples of twins residing in the state of Colorado. Results indicated that cross-sectional mean levels for NS, HA and RD tended to show modest increases across the adolescent years, while PS showed modest mean decreases. Consistent sex differences in means were found only for RD. Univariate biometrical twin models were used to decompose trait variance into genetic and environmental sources. Results indicated that for NS, HA and RD additive genetic influences and unique environmental effects were sufficient to explain the data. PS, however, could be explained by unique and common environmental effects only, with different patterns of common environmental effects for males and females. We found moderate heritability estimates for NS, HA and RD ranging from .28 to .36--with no evidence for sex-limitation in those influences.

Modification, Cross-Validation, Invariance, and Latent Mean Structure of the Self-Presentation in Exercise Questionnaire

The Self-Presentation in Exercise Questionnaire (SPEQ; Conroy, Motl, & Hall, 2000) measures impression motivation (IM) and impression construction (IC) within the context of exercise. This study cross-validated 2 published models of SPEQ scores, evaluated the invariance of the SPEQ model between sexes, and tested for sex differences in latent means for IM and IC. Based on data from 711 adult exercisers, published models of SPEQ scores were found to be inadequate, and a specification search yielded a revised model comprising 2 correlated factors. This model demonstrated tight cross-validity in an independent sample of adult exercisers. Invariance of the scale between women and men also was supported. No sex difference existed in latent IM scores but men exhibited a higher IC latent mean than women. Priorities for future evaluations of the SPEQ include examining the invariance of the model in other populations and extending evidence for the validity of score interpretations.

Sex Differences in Variability in Intellectual Abilities: A New Look at an Old Controversy

Contemporary research on sex differences in intellectual abilities has focused on male-female differences in average performance, implicitly assuming homogeneity of variance. To examine the validity of that assumption, this article examined sex differences in variability on the national norms of several standardized test batteries. Males were consistently more variable than females in quantitative reasoning, spatial visualization, spelling, and general knowledge. Because these sex differences in variability were coupled with corresponding sex differences in means, it was demonstrated that sex differences in variability and sex differences in central tendency have to be considered together to form correct conclusions about the magnitude of cognitive gender differences.

Sex Differences in Variability in Intellectual Abilities: A New Look at an Old Controversy

Contemporary research on sex differences in intellectual abilities has focused on male-female differences in average performance, implicitly assuming homogeneity of variance. To examine the validity of that assumption, this article examined sex differences in variability on the national norms of several standardized test batteries. Males were consistently more variable than females in quantitative reasoning, spatial visualization, spelling, and general knowledge. Because these sex differences in variability were coupled with corresponding sex differences in means, it was demonstrated that sex differences in variability and sex differences in central tendency have to be considered together to form correct conclusions about the magnitude of cognitive gender differences.

Age‐ and sex‐associated variations in the directional asymmetry of rhesus macaque forelimb bones

Several investigators have questioned the significance of handedness as an explanation of directional forelimb asymmetries, yet little has been done to isolate other explanatory factors. In this investigation, we analyze 61 female and 76 male rhesus macaque skeletons for evidence of age- and/or sex-associated variations in ten forelimb bone measurements. All significant directional asymmetries are found to favor the right side. Although some of these asymmetries are found to favor the right side. Although some of these asymmetries are compatible with the interpretation of muscle hypertrophy associated with preferential use of the right forelimb, the overall pattern suggests that age- and sex-related ontogenetic factors deserve equal consideration. Significant sex differences in asymmetry means are present within and across age groups (juveniles, subadults, and adults), and numerous changes in asymmetry with age are also found. A pattern of decreasing asymmetry with age was found in males, with 40% of the ten measures being asymmetrical in juveniles, 30% in subadults, and 20% in adults. Among females, this pattern is reversed. No significant asymmetries were found for juvenile or subadult females, whereas 40% of the measures were asymmetrical in adult females. We conclude that greater consideration of age- and sex-related factors is necessary when drawing samples for the purpose of investigating asymmetries, and an awareness of trait-specific age and sex patterns of variation is necessary when citing forelimb asymmetries in demographically nonrepresentative populations as evidence of handedness or other behavioral asymmetries.