Sex Differences In Intelligence Research Articles

Intelligence

Individual differences in human intelligence are of interest to a wide range of psychologists and to many people outside the discipline. This overview of contributions to intelligence research covers the first decade of the twenty-first century. There is a survey of some of the major books that appeared since 2000, at different levels of expertise and from different points of view. Contributions to the phenotype of intelligence differences are discussed, as well as some contributions to causes and consequences of intelligence differences. The major causal issues covered concern the environment and genetics, and how intelligence differences are being mapped to brain differences. The major outcomes discussed are health, education, and socioeconomic status. Aging and intelligence are discussed, as are sex differences in intelligence and whether twins and singletons differ in intelligence. More generally, the degree to which intelligence has become a part of broader research in neuroscience, health, and social science is discussed.

Sex differences in intelligence in younger and older participants of the Raven’s Standard Progressive Matrices Plus

After many years of inconclusive findings in the well-researched field of sex differences in general intelligence, Lynn (1994) made a novel contribution by proposing a developmental theory to explain differences in mean performance on measures of general intelligence. The theory posits that due to differing maturational rates, females outperform males prior to 15years of age, while males outperform females from 15years of age onwards through adulthood. The Raven’s Progressive Matrices are often used in such investigations of group differences as they are considered to be among the best measures of general intelligence. To date, inconsistent results have been reported and may be attributed to the non-representative nature of the data samples and the use of statistical measures that fail to identify test item bias or the reliable evaluation of group differences. Using a nationally representative sample of children, multiple-group confirmatory factor analyses have been used to assess mean differences in younger (7–14years) and older (15–18years) groups. No significant differences were found in mean performance or score variance, failing to provide evidence for a Developmental Theory of Sex Differences in general intelligence.

A longitudinal study of sex differences in intelligence at ages 7, 11 and 16 years

This paper presents the results of a longitudinal study of sex differences in intelligence as a test of Lynn’s (1994) hypothesis that from the age of 16years males develop higher average intelligence than females. The results show that at the ages of 7 and 11years girls have an IQ advantage of approximately 1 IQ point, but at the age of 16years this changes in the same boys and girls to an IQ advantage of 1.8 IQ points for boys.

A conversation with Richard Lynn

This special issue - Evolution of race and sex differences in intelligence and personality: Tribute to Richard Lynn at eighty – testifies to his many research interests over time, where Richard often pioneered. To mention a few examples, he clarified the confusion about the existence of an average sex difference in IQ, by demonstrating that children below 15 do not show the later adult sex difference. More importantly, Richard was the first to establish average IQs for all countries with more than 40.000 people, and then, with Tatu Vanhanen, illustrated the impressive predictive power of these IQs for understanding essential aspects of a nation’s economical and social infrastructure. Richard was also the first to realise that classical eugenic measures do not suffices to avert serious consequences of dysgenics and to suggest that modern reproductive technologies may entail better eugenic potentials.The present conversation provides sufficient details to get a glimpse of the person behind these pioneering efforts this and of his courage. As a prominent member of the London School of Differential Psychology he paints broad consequential strokes on our deeper understanding of human nature and what makes civilizations rise and fall. The behavioural sciences need extraordinary people like him.

Gender differences in variance and means on the Naglieri Non‐verbal Ability Test: Data from the Philippines

Research on gender differences in intelligence has focused mostly on samples from Western countries and empirical evidence on gender differences from Southeast Asia is relatively sparse. This article presents results on gender differences in variance and means on a non-verbal intelligence test using a national sample of public school students from the Philippines. More than 2,700 sixth graders from public schools across the country were tested with the Naglieri Non-verbal Ability Test (NNAT). Variance ratios (VRs) and log-transformed VRs were computed. Proportion ratios for each of the ability levels were also calculated and a chi-square goodness-of-fit test was performed. An analysis of variance was performed to determine the overall gender difference in mean scores as well as within each of three age subgroups. Our data show non-existent or trivial gender difference in mean scores. However, the tails of the distributions show differences between the males and females, with greater variability among males in the upper half of the distribution and greater variability among females in the lower half of the distribution. Descriptions of the results and their implications are discussed. Results on mean score differences support the hypothesis that there are no significant gender differences in cognitive ability. The unusual results regarding differences in variance and the male-female proportion in the tails require more complex investigations.

Gender Differences in Emotional Intelligence

The stereotype of women being more 'emotional' sex survives to this day. The present study was conducted to empirically validate this affirmation. Two hundred thirty eight engineering graduates (males=110, females=128)in the age range of 21-25 years formed the sample of the study. The gender differences on various dimensions of Emotional Intelligence were explored with the help of a self-report measure of Emotional Intelligence that included (a) self -awareness (b) empathy (c) self-motivation (d) emotional stability (e) managing relations (f) integrity (g) self-development (h) value orientation (i) commitment and (j) altruistic behavior. The data was analyzed using independent sample't' test. Results of the study indicate a significantly higher score of female students on selfawareness, self-motivation, managing relations, integrity and overall emotional intelligence in comparison to the male students. The difference on other dimensions of Emotional Intelligence was statistically insignificant.

Domain-specific school achievement in boys and girls as predicted by intelligence, personality and motivation

This study investigates whether sex differences in school achievement in three domains are associated with sex differences in intelligence, personality and school-related motivation. In a sample of 1353 Austrian eight graders (552 males, 801 females; mean age 13.74 years, SD = .47), intelligence, the Big Five personality factors as well as domain-specific school anxiety, ability self-perceptions and interests were assessed as predictors of grades in German, Math and English. Most predictors yielded significant mean differences between sexes. Intelligence and ability self-perceptions were the strongest predictors of grades in all domains. In Math, additional predictors of grades were Conscientiousness and Neuroticism. Grades in German and English were also predicted by the interaction between sex and Extraversion. While for girls a higher level of Extraversion was associated with better grades, the opposite was true for boys. Only in German, there was an additional interaction between sex and verbal intelligence indicating that girls benefit even more than boys from a high level of verbal intelligence.

Self‐ and other‐estimates of multiple abilities in Britain and Turkey: A cross‐cultural comparison of subjective ratings of intelligence

This study is part of a programmatic research effort into the determinants of self-assessed abilities. It examined cross-cultural differences in beliefs about intelligence and self- and other-estimated intelligence in two countries at extreme ends of the European continent. In all, 172 British and 272 Turkish students completed a three-part questionnaire where they estimated their parents', partners' and own multiple intelligences (Gardner (10) and Sternberg (3)). They also completed a measure of the 'big five' personality scales and rated six questions about intelligence. The British sample had more experience with IQ tests than the Turks. The majority of participants in both groups did not believe in sex differences in intelligence but did think there were race differences. They also believed that intelligence was primarily inherited. Participants rated their social and emotional intelligence highly (around one standard deviation above the norm). Results suggested that there were more cultural than sex differences in all the ratings, with various interactions mainly due to the British sample differentiating more between the sexes than the Turks. Males rated their overall, verbal, logical, spatial, creative and practical intelligence higher than females. Turks rated their musical, body-kinesthetic, interpersonal and intrapersonal intelligence as well as existential, naturalistic, emotional, creative, and practical intelligence higher than the British. There was evidence of participants rating their fathers' intelligence on most factors higher than their mothers'. Factor analysis of the ten Gardner intelligences yield two clear factors: cognitive and social intelligence. The first factor was impacted by sex but not culture; it was the other way round for the second factor. Regressions showed that five factors predicted overall estimates: sex (male), age (older), test experience (has done tests), extraversion (strong) and openness (strong). Results are discussed in terms of the growing literature in the field.

Sex differences in self‐estimation of multiple intelligences among Portuguese adolescents

This study investigated the relationship among sex, attitude toward intelligence, and self‐estimation of multiple intelligences for self and parents among Portuguese adolescents in secondary schools. Two hundred and forty‐two adolescents estimated their own and their parents' IQ scores on each of Gardner's 10 multiple intelligences: verbal (linguistic), logical (mathematical), spatial, musical, body‐kinesthetic, interpersonal, intrapersonal, existential, spiritual, and naturalistic. They also answered six simple questions concerning intelligence and intelligence tests. There were various sex differences in self‐estimated IQ: males rated themselves higher on overall, mathematical, spatial, intrapersonal, spiritual, and naturalistic IQ compared with females. Multiple regressions indicated that verbal, logical, and intrapersonal intelligence were significant predictors for self and parents overall IQ estimations. Factor analysis of the 10, the 8, and the 7 self‐estimates scores did not confirm Gardner's classification of multiple intelligences. Males were more likely to believe in sex differences in intelligence than females. Results are discussed in terms of the growing literature in the self‐estimates of intelligence, as well as limitations of that approach.

Are apparent sex differences in mean IQ scores created in part by sample restriction and increased male variance?

This study investigated the possibility that apparent sex differences in IQ are at least partly created by the degree of sample restriction from the baseline population. We used a nationally representative sample, the 1970 British Cohort Study. Sample sizes varied from 6518 to 11,389 between data-collection sweeps. Principal components analysis of scores obtained on four cognitive tests administered at age 10 was used to obtain estimates that we name ‘IQ’. These age-10 scores were then used to estimate the sex differences at age 10, and also among participants in the two later waves, at age 26 and 30. At age 10, there was a small but significant advantage for boys (Cohen’s d = 0.081). Boys had greater variability in these IQ scores. We then investigated how this very small male advantage at 10 changed with sample restriction. We used the same IQs obtained at age 10, but considered only those subjects who returned for data-collection sweeps at ages 26 and 30 years. Subjects returning at age 26 and 30 were more likely to be females and to have higher age-10 IQ scores. Attrition at age 30 was 28% and the male advantage in IQ scores increased by 15%. Attrition at age 26 was 43% and the male advantage in IQ scores increased by 48%. The findings underline the importance of monitoring attrition in longitudinal studies, as well as emphasising the need for representative samples in studying sex differences in intelligence. A proportion of the apparent male advantage in general cognitive ability that has been reported by some researchers might be attributable to the combination of greater male variance in general cognitive ability and sample restriction, though this remains to be tested in a sample with an appropriate mental test battery.

Predicting school achievement in boys and girls

This study investigates the extent to which girls' better school attainment is associated with sex differences in intelligence, personality and school‐related motivation. In a sample of 1353 Austrian pupils (mean age 13.74 years), intelligence, the Big Five of personality, self‐esteem, school anxiety, school‐related intrinsic motivation and achievement goals were assessed as predictors and GPA as achievement criterion. Most predictors yielded significant mean differences between sexes and some of the variables predicted school achievement only for boys or only for girls. Intelligence and self‐esteem were the strongest predictors of GPA for both sexes, and school‐related intrinsic motivation, school anxiety and performance‐avoidance goals explained additional variance in GPA only for boys, whereas work avoidance did so only for girls. Copyright © 2008 John Wiley & Sons, Ltd.

Gender Differences in Intelligence and Achievement in Gifted Spanish Children

The purpose of this investigation is to determine whether there are gender differences in intelligence and achievement among gifted Spanish children. The sample is made up of 110 students of high ability (42 girls and 68 boys) coming from various Spanish educational centers and selected to attend an enrichment program. Their age ranged between 6 and 16 years. Data relating to the administration of the WISC-R and achievement in their school were amalgamated. The results reveal some signifi cant differences in intelligence and achievement. Girls scored higher than boys in Performance IQ and Full Scale IQ, whereas boys scored higher in achievement. Differences were also noted in terms of function and educational level. Secondary students performed better than those in primary education.

Considerations Relating to the Study of Group Differences in Intelligence.

There are signs that the debate over racial and gender differences in intelligence is about to begin again. In this article we will be concerned primarily with racial differences but will make remarks about gender differences where applicable. Previously there have been bitter arguments over whether or not races exist, over whether it is either important or proper to study racial and gender differences in intelligence, and over the conclusions that have been drawn about environmental and genetic causes as determinants of these differences. We argue that races do, indeed, exist and that studying differences in cognitive competence between groups is a reasonable thing to do. We also point out that past research on both racial and gender differences in intelligence has been marked by methodological errors and overgeneralizations by researchers on all sides of the issue. We propose ten principles of design, analysis, and reporting that ought to be considered carefully when doing or evaluating research in this area.

Sex-related differences in general intelligence g, brain size, and social status

The question of a sex difference in intelligence has long divided the experts. IQ researchers sum standardized subtest scores to calculate intelligence in general, and find that males outscore females by about 3.8 points, whereas factor analysts derive the g factor scores from intertest-correlations and find no consistent sex differences in general intelligence. The latter finding is puzzling, as males have larger average brains than females, and brain size correlates .30–.45 with g (and IQ). Males thus “ought” to score a higher g than females. The present study addressed this paradox by testing four hypotheses: (1) Inadequate analyses explain why researchers get inconsistent results, (2) The proper method will identify a male g lead, (3) The larger male brain “explains” the male g lead, (4) The higher male g average and wider distribution transform into an exponentially increased male–female ratio at the high end of the g distribution, and this largely explains male dominance in society. All four hypotheses obtained support and explain in part why relatively few males dominate the upper strata in all known societies. The confirmation of hypothesis 3 suggests that the brain size—intelligence–dominance link may be partly biological.

Differences in Gender and Ethnicity as Measured by Ratings of Three Writing Tasks

AbstractThe issue of racial/ethnic and gender differences in intelligence and academic abilities is fiercely and frequently debated, yet the examination of these differences in creativity is less studied. Our goal in this study was to use the Consensual Assessment Technique, in which experts judge a product's creativity, to examine differences in creativity among gender and ethnic groups. We conducted three separate analyses in which 13 experts rated 103 poems, 104 fictional stories, and 103 personal narratives written by Caucasian, African American, Latino/a, and Asian eighth‐grade students. There were no significant African American‐Caucasian differences on any of the writing tasks and there were no gender differences on all three tasks. The only significant differences in the creativity ratings on any of the tasks occurred in poetry, between the Latino/ a‐Caucasian groups and Latino/a‐Asian groups. Implications and future directions are discussed.

Testing the developmental theory of sex differences in intelligence on 12–18 year olds

Abstract The consensus view states that there are no sex differences in intelligence. However, Lynn (1994, 1999) has formulated a developmental theory of sex differences in intelligence that challenges that view. The theory states that boys and girls mature at different rates such that the growth of girls accelerates at the age of about 9 years and remains in advance of boys until 14–15 years. At 15–16 years the growth of girls decelerates relative to boys. As boys continue to grow from this age their height and their mean IQs increase relative to those of girls. This paper presents new evidence for the theory from the Spanish standardization sample of the fifth edition of the DAT. 1027 boys and 924 girls between 12 and 18 years were tested. The general trend shows that girls do better at the younger ages and their performance declines relative to boys among older age groups, which supports the developmental theory. The sex difference for the DAT as a whole for 18 year olds is a 4.3 IQ advantage for boys, very close to the advantage that can be predicted from their larger brain size (4.4 IQ points). The profile of sex differences in abilities among the Spanish sample is closely similar to that in the United States and Britain, which is testimony to the robustness of the difference in these different cultures.

Lucy's Legacy: Sex and Intelligence in Human Evolution:Lucy's Legacy: Sex and Intelligence in Human Evolution.

Lucy's Legacy: Sex and Intelligence in Human Evolution. Alison Jolly. Cambridge, MA: Harvard University Press, 1999.518 pp.

Sex differences in brain size, stature and intelligence in children and adolescents: some evidence from Estonia

Abstract Sex differences in brain size and stature decrease from the age of 7 through 13–14 years and increase from the age of 15 through 18 years in Estonia, as they do in the United States. Sex differences in intelligence show a somewhat similar decrease and increase although they do not move precisely in synchrony with the morphological trends. The results are interpreted as suggesting that sex differences in maturation determine the magnitude of sex differences in physical and mental development during childhood and adolescence.

The Smarter Sex: A Critical Review of Sex Differences in Intelligence

Although there are no sex differences in general intelligence, reliable differences are found on some tests of cognitive abilities. Many of the tasks that assess the ability to manipulate visual images in working memory show an advantage for males, whereas many of the tasks that require retrieval from long-term memory and the acquisition and use of verbal information show a female advantage. Large effects favoring males are also found on advanced tests of mathematical achievement, especially with highly select samples. Males are also overrepresented in some types of mental retardation. Effects sizes are variable and often large. These differences are generally found cross-culturally and across the life span. The nature–nurture dichotomy is rejected as an interpretive framework. In light of recent findings that environmental variables alter the biological underpinnings of intelligence and individuals actively participate in creating their environments, we prefer a psychobiosocial model for understanding sex differences in intelligence.

Discussion

Here we test the developmental theory of sex differences in intelligence using latent modeling. The theory has been recently updated (Lynn, 2017). Based on men's greater average brain volumes and premature maturation in women, the theory predicts an intelligence advantage for women (or null sex differences) in early adolescence, but an advantage for men in late adolescence. The findings reported by Lynn are consistent with the theory, but basic measurement issues were not met. Are we taping the same construct regardless of sex and age and can we provide sound conclusions? We considered 10,335 individuals (4992 boys and 5343 girls) within an age range of 12–18 years. They completed the subtests included in the TEA Ability Battery (BAT-7). Theta scores for each subtest were estimated using a three-parameter logistic Item Response Theory model (3PL IRT). Results fitted properly to invariance criteria across age and sex. Latent estimates for the general factor of intelligence (g) were used for testing the theory. The observed findings were in agreement with the developmental theory: there were null sex differences at 12 years of age, but there was an average difference favoring boys equivalent to 5 IQ points at 18 years of age.