3. Are there sex differences in intelligence?

2020 ◽  
pp. 39-49
Author(s):  
Ian J. Deary
Keyword(s):  
Young Adults ◽  
Sex Differences ◽  
Cognitive Abilities ◽  
Longitudinal Survey ◽  
National Longitudinal Survey ◽  
Data Sets ◽  
General Intelligence ◽  
Average Difference ◽  
Cognitive Domains ◽  
Cognitive Abilities Test

‘Are there sex differences in intelligence?’ considers the data sets from the Scottish Mental Survey of 1932, the National Longitudinal Survey of Youth from 1979, and the Cognitive Abilities Test 3 sample from 2001–3. All three studies show that there is little evidence of any average difference in intelligence between boys and girls, or young adults. However, for overall general intelligence, there are slightly more girls than boys in these samples around the average scores, and proportionately more males than females at the higher and lower extremes. Among the cognitive domains, a different pattern occurred for verbal reasoning: there were more girls at the higher scores.

A Role for the X Chromosome in Sex Differences in Variability in General Intelligence?

2009 ◽  
Vol 4 (6) ◽  
pp. 598-611 ◽  
Author(s):  
Wendy Johnson ◽  
Andrew Carothers ◽  
Ian J. Deary
Keyword(s):  
Sex Differences ◽  
Mental Retardation ◽  
X Chromosome ◽  
Cognitive Abilities ◽  
Population Distribution ◽  
Population Variation ◽  
General Intelligence ◽  
Substantial Evidence ◽  
Normal Distributions ◽  
Intellectual Abilities

There is substantial evidence that males are more variable than females in general intelligence. In recent years, researchers have presented this as a reason that, although there is little, if any, mean sex difference in general intelligence, males tend to be overrepresented at both ends of its overall distribution. Part of the explanation could be the presence of genes on the X chromosome related both to syndromal disorders involving mental retardation and to population variation in general intelligence occurring normally. Genes on the X chromosome appear overrepresented among genes with known involvement in mental retardation, which is consistent with a model we developed of the population distribution of general intelligence as a mixture of two normal distributions. Using this model, we explored the expected ratios of males to females at various points in the distribution and estimated the proportion of variance in general intelligence potentially due to genes on the X chromosome. These estimates provide clues to the extent to which biologically based sex differences could be manifested in the environment as sex differences in displayed intellectual abilities. We discuss these observations in the context of sex differences in specific cognitive abilities and evolutionary theories of sexual selection.

scholarly journals Within-person structures of daily cognitive performance differ from between-person structures of cognitive abilities

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9290 ◽  
Author(s):  
Florian Schmiedek ◽  
Martin Lövdén ◽  
Timo von Oertzen ◽  
Ulman Lindenberger
Keyword(s):  
Working Memory ◽  
Young Adults ◽  
Cognitive Abilities ◽  
Cognitive Tasks ◽  
Human Intelligence ◽  
General Factor ◽  
General Intelligence ◽  
Common Variance ◽  
Using Data ◽  
Over Time

Over a century of research on between-person differences has resulted in the consensus that human cognitive abilities are hierarchically organized, with a general factor, termed general intelligence or “g,” uppermost. Surprisingly, it is unknown whether this body of evidence is informative about how cognition is structured within individuals. Using data from 101 young adults performing nine cognitive tasks on 100 occasions distributed over six months, we find that the structures of individuals’ cognitive abilities vary among each other, and deviate greatly from the modal between-person structure. Working memory contributes the largest share of common variance to both between- and within-person structures, but the g factor is much less prominent within than between persons. We conclude that between-person structures of cognitive abilities cannot serve as a surrogate for within-person structures. To reveal the development and organization of human intelligence, individuals need to be studied over time.

scholarly journals Within-person structures of daily cognitive performance cannot be inferred from between-person structures of cognitive abilities

2019 ◽  
Author(s):  
Florian Schmiedek ◽  
Martin Lövdén ◽  
Timo von Oertzen ◽  
Ulman Lindenberger
Keyword(s):  
Working Memory ◽  
Young Adults ◽  
Cognitive Abilities ◽  
Cognitive Tasks ◽  
Human Intelligence ◽  
General Factor ◽  
General Intelligence ◽  
Common Variance ◽  
Using Data ◽  
Over Time

Over a century of research on between-person differences has resulted in the consensus that human cognitive abilities are hierarchically organized, with a general factor, termed general intelligence or “g,” uppermost. Surprisingly, it is unknown whether this body of evidence is informative about how cognition is structured within individuals. Using data from 101 young adults performing nine cognitive tasks on 100 occasions distributed over six months, we find that the structures of individuals’ cognitive abilities vary among each other, and deviate greatly from the modal between-person structure. Working memory contributes the largest share of common variance to both between- and within-person structures, but the g factor is much less prominent within than between persons. We conclude that between-person structures of cognitive abilities cannot serve as a surrogate for within-person structures. To reveal the development and organization of human intelligence, individuals need to be studied over time.

scholarly journals Within-person structures of daily cognitive performance cannot be inferred from between-person structures of cognitive abilities

2019 ◽  
Author(s):  
Florian Schmiedek ◽  
Martin Lövdén ◽  
Timo von Oertzen ◽  
Ulman Lindenberger
Keyword(s):  
Working Memory ◽  
Young Adults ◽  
Cognitive Abilities ◽  
Cognitive Tasks ◽  
Human Intelligence ◽  
General Factor ◽  
General Intelligence ◽  
Common Variance ◽  
Using Data ◽  
Over Time

Over a century of research on between-person differences has resulted in the consensus that human cognitive abilities are hierarchically organized, with a general factor, termed general intelligence or “g,” uppermost. Surprisingly, it is unknown whether this body of evidence is informative about how cognition is structured within individuals. Using data from 101 young adults performing nine cognitive tasks on 100 occasions distributed over six months, we find that the structures of individuals’ cognitive abilities vary among each other, and deviate greatly from the modal between-person structure. Working memory contributes the largest share of common variance to both between- and within-person structures, but the g factor is much less prominent within than between persons. We conclude that between-person structures of cognitive abilities cannot serve as a surrogate for within-person structures. To reveal the development and organization of human intelligence, individuals need to be studied over time.

7. Does intelligence matter in the school and the workplace?

2020 ◽  
pp. 91-101
Author(s):  
Ian J. Deary
Keyword(s):  
United Kingdom ◽  
Cognitive Abilities ◽  
Educational Outcomes ◽  
Test Scores ◽  
Psychometric Testing ◽  
Intelligence Test ◽  
After School ◽  
General Intelligence ◽  
Cognitive Abilities Test ◽  
Intelligence Test Scores

Do intelligence test scores have some predictive power? Can they predict who will do well in achieving more and better educational qualifications, and after school, can they predict who will perform well in the workplace? ‘Does intelligence matter in the school and the workplace?’ looks at the use of the Cognitive Abilities Test in United Kingdom schools and its correlation with GCSE results five years later. The correlation is high: people’s intelligence differences at age 11 are a powerful predictor of their differences in educational outcomes at age 16. In the workplace, the use of general intelligence/psychometric testing in selecting people for work is worthwhile. Intelligence predicts occupational and educational successes.

Mothers' Income and Young Adult Children's Education and Fast Food Intake

2020 ◽  
Vol 44 (5) ◽  
pp. 681-690
Author(s):  
Jaewon Lee ◽  
Jennifer Allen
Keyword(s):  
Young Adults ◽  
Young Adult ◽  
Educational Attainment ◽  
Food Consumption ◽  
Fast Food ◽  
Longitudinal Survey ◽  
Economic Resources ◽  
National Longitudinal Survey ◽  
Fast Food Consumption ◽  
The Relationship

Objectives: In this study, we examine young adult children's educational attainment as a mediator in the pathway from their mother's income to their fast food consumption. Methods: The National Longitudinal Survey of Youth 1979 (NLSY79) and the National Longitudinal Survey of Youth 79 for Children and Young Adults (NLSY79 CY) were used to select mother and children dyads. A total of 5140 dyads were selected as the final sample. We used a mediation model to test mediators in the relationship between mother's income and young adult children's fast food consumption. Results: Mother's income was significantly related to their young adult children's educational attainment. Mother's income was negatively related to fast food consumption. This study revealed partial mediation of the relationship between mother's income and their young adult children's fast food consumption via their young adult children's educational attainment. Conclusions: A new perspective considering mother's economic resources is needed to understand children's education. Mother's income is important to cultivate their young adult children's health behaviors. The intergenerational transmission of mother's economic resources to their young adult children's educational attainment should be considered to understand young adults' fast food consumption.

The Role of Young Adult Children’s Income in the Relationship between Single Mothers’ Poverty and Their Young Adult Children’s Depression

2021 ◽  
pp. 0192513X2098449
Author(s):  
Jaewon Lee ◽  
Jennifer Allen
Keyword(s):  
Young Adults ◽  
Young Adult ◽  
Single Mothers ◽  
Adult Children ◽  
Longitudinal Survey ◽  
Mediating Effect ◽  
National Longitudinal Survey ◽  
Income Poverty ◽  
Children’S Depression ◽  
The Relationship

This study examined the relationship between single mother’s poverty and their young adult children’s depression, and it examined the mediating effect of young adults’ income on the relationship. The National Longitudinal Survey of Youth 1979 (NLSY79) and the National Longitudinal Survey of Youth 79 for Children and Young Adults (NLSY79 CY) were used. A total of 4,224 dyads were selected and the mediation model was conducted. Single mother’s poverty was related to low income and depression among their young adult children. The relationship between mother’s poverty and their young adult children’s depression was partially mediated by their young adult children’s income. Poverty prevention or reduction programs for female-headed households should be provided to single mothers to reduce future levels of depression among their young adults. Improving inequality in intergenerational economic mobility is one way to address depressive symptoms among the young adult children of single mothers in poverty.

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

2021 ◽  
Vol 8 (7) ◽  
pp. 210239
Author(s):  
Zegni Triki ◽  
Redouan Bshary
Keyword(s):  
Sex Differences ◽  
Inhibitory Control ◽  
Cognitive Abilities ◽  
Control Task ◽  
Cognitive Domains ◽  
Labroides Dimidiatus ◽  
Assessment Task ◽  
Food Quantity ◽  
Learning Tasks ◽  
Relevant Task

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.

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