Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Biological Influences on Intelligence01:30

Biological Influences on Intelligence

688
Intelligence is often thought to be linked to brain size, but the relationship is more complex than that. While brain size does correlate modestly with some abilities, like verbal skills, the connection is weaker for others, such as spatial reasoning. Other factors, like brain structure, also play crucial roles. For instance, despite Einstein's smaller-than-average brain, his parietal cortex, which is involved in spatial reasoning, was 15% wider, suggesting that neural density might matter...
688
Environmental Influences on Intelligence01:29

Environmental Influences on Intelligence

1.1K
Despite the strong genetic influence on traits like intelligence, environmental factors significantly shape outcomes. For example, while over 90% of height variation is due to genetic differences, environmental factors such as nutrition also have a notable impact. Similarly, for intelligence, changes in a child's surroundings can significantly alter their IQ. Research shows that enriched environments boost children's academic success and help them develop key cognitive skills. Children...
1.1K
Intelligence01:27

Intelligence

10.0K
The term "intelligence" is complex because it refers to both behavior and individuals, and its interpretation varies across cultures. European Americans tend to link intelligence with reasoning and cognitive skills, while in Kenya, it is tied to responsible participation in family and social life. In Uganda, intelligence is seen as the ability to know the right actions and carry them out effectively, while the Iatmul people of Papua New Guinea associate it with the capacity to remember...
10.0K
Measures of Intelligence01:29

Measures of Intelligence

9.8K
Psychologists measure intelligence by using standardized tests that produce a score known as the intelligence quotient or IQ. To understand IQ tests, it's important to recognize the key principles behind their construction: validity, reliability, and standardization.
Validity refers to how well a test measures what it claims to measure. An intelligence test should accurately assess intelligence rather than another characteristic, like anxiety. Criterion validity is one way to evaluate this;...
9.8K
Wechsler's Contribution to Measures of Intelligence01:23

Wechsler's Contribution to Measures of Intelligence

2.5K
David Wechsler, a psychologist who worked with World War I veterans, developed a significant IQ test in 1939 called the Wechsler-Bellevue Intelligence Scale. This test was innovative because it combined several subtests that measured both verbal and nonverbal skills, reflecting Wechsler's belief that intelligence is a global capacity involving purposeful action, rational thinking, and effective interaction with the environment. This test later evolved into the Wechsler Adult Intelligence...
2.5K
Cattell's Theory of Intelligence01:25

Cattell's Theory of Intelligence

8.7K
Raymond Cattell, along with John Horn, made significant contributions to our understanding of intelligence by distinguishing between two types: fluid intelligence and crystallized intelligence.
Fluid intelligence involves the capacity to solve new problems and adapt to unfamiliar situations. It's the type of intelligence individuals use when they encounter a novel problem or puzzle that requires innovative thinking. For instance, figuring out how to operate a new gadget relies heavily on...
8.7K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

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

Perspectives on psychological science : a journal of the Association for Psychological Science·2015
Same author

Speculation to Inform and Speculation to Explore: Response to Craig et al. (2009) and Turkheimer & Halpern (2009).

Perspectives on psychological science : a journal of the Association for Psychological Science·2015
Same author

Meta-analysis of Genome-wide Association Studies for Neuroticism, and the Polygenic Association With Major Depressive Disorder.

JAMA psychiatry·2015
Same author

Reaction time in adolescence, cumulative allostatic load, and symptoms of anxiety and depression in adulthood: the West of Scotland Twenty-07 Study.

Psychosomatic medicine·2015
Same author

Independent evidence for an association between general cognitive ability and a genetic locus for educational attainment.

American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics·2015
Same author

Intelligence in childhood and atherosclerosis of the carotid and peripheral arteries in later life: the Lothian Birth Cohort 1936.

PloS one·2015
Same journal

Children's Third-Party Punishment Reveals a Genuine Concern for Fairness and Justice.

Perspectives on psychological science : a journal of the Association for Psychological Science·2026
Same journal

Chaos Theory and Child Development: Quantifying Nonlinear Pathways of Growth.

Perspectives on psychological science : a journal of the Association for Psychological Science·2026
Same journal

Formal Modeling as Theoretical Glue between Laboratory and Naturalistic Studies of Memory.

Perspectives on psychological science : a journal of the Association for Psychological Science·2026
Same journal

Growing Technological Opacity and the Social Brain.

Perspectives on psychological science : a journal of the Association for Psychological Science·2026
Same journal

Bringing the Reading Sciences Into the Classroom: Insights for Phonics Instruction.

Perspectives on psychological science : a journal of the Association for Psychological Science·2026
Same journal

From Voice to Self: An Integrative Framework on Self-Voice Processing.

Perspectives on psychological science : a journal of the Association for Psychological Science·2026
See all related articles

Related Experiment Video

Updated: Apr 7, 2026

Author Spotlight: Validation of SICOLE-R for Assessing Cognitive and Reading Skills in Spanish-Speaking Children and Its Role in Personalized Education
09:00

Author Spotlight: Validation of SICOLE-R for Assessing Cognitive and Reading Skills in Spanish-Speaking Children and Its Role in Personalized Education

Published on: August 16, 2024

1.3K

Sex Differences in Variability in General Intelligence: A New Look at the Old Question.

Wendy Johnson1, Andrew Carothers2, Ian J Deary3

  • 1MRC Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, United Kingdom Department of Psychology, University of Minnesota-Twin Cities wendy.johnson@ed.ac.uk.

Perspectives on Psychological Science : a Journal of the Association for Psychological Science
|July 10, 2015
PubMed
Summary
This summary is machine-generated.

Males exhibit greater variability in general intelligence than females, particularly at the lower end of the distribution. This finding challenges assumptions about intelligence distribution and sex differences in cognitive abilities.

More Related Videos

Assessment of Spontaneous Alternation, Novel Object Recognition and Limb Clasping in Transgenic Mouse Models of Amyloid-β and Tau Neuropathology
10:02

Assessment of Spontaneous Alternation, Novel Object Recognition and Limb Clasping in Transgenic Mouse Models of Amyloid-β and Tau Neuropathology

Published on: May 28, 2017

28.4K
Hypoxia Alters miRNAs Levels Involved in Non-Mendelian Inheritance of Autism Spectrum Disorder in Mice
09:13

Hypoxia Alters miRNAs Levels Involved in Non-Mendelian Inheritance of Autism Spectrum Disorder in Mice

Published on: July 11, 2025

35.2K

Related Experiment Videos

Last Updated: Apr 7, 2026

Author Spotlight: Validation of SICOLE-R for Assessing Cognitive and Reading Skills in Spanish-Speaking Children and Its Role in Personalized Education
09:00

Author Spotlight: Validation of SICOLE-R for Assessing Cognitive and Reading Skills in Spanish-Speaking Children and Its Role in Personalized Education

Published on: August 16, 2024

1.3K
Assessment of Spontaneous Alternation, Novel Object Recognition and Limb Clasping in Transgenic Mouse Models of Amyloid-β and Tau Neuropathology
10:02

Assessment of Spontaneous Alternation, Novel Object Recognition and Limb Clasping in Transgenic Mouse Models of Amyloid-β and Tau Neuropathology

Published on: May 28, 2017

28.4K
Hypoxia Alters miRNAs Levels Involved in Non-Mendelian Inheritance of Autism Spectrum Disorder in Mice
09:13

Hypoxia Alters miRNAs Levels Involved in Non-Mendelian Inheritance of Autism Spectrum Disorder in Mice

Published on: July 11, 2025

35.2K

Area of Science:

  • Psychology
  • Human Genetics
  • Educational Psychology

Background:

  • Historically, general intelligence is hypothesized to be more variable in males than females.
  • This hypothesis suggests males are overrepresented at the extreme ends of the intelligence distribution.
  • Empirical analysis of large, representative samples is needed to clarify these sex differences in intelligence variability.

Purpose of the Study:

  • To investigate sex differences in the distribution of general intelligence.
  • To examine variability in general intelligence across different ranges of the distribution.
  • To test a mixture model explaining population intelligence distribution.

Main Methods:

  • Analysis of two population-wide general intelligence surveys of 11-year-olds in Scotland.
  • Examination of the normality and variability of intelligence score distributions.
  • Comparison of male and female intelligence variability, especially at higher score ranges.

Main Results:

  • Intelligence distributions showed significant departures from normality, with lower variability at the higher end.
  • Modal IQ scores were approximately 105, despite a mean IQ of 100.
  • Males demonstrated greater variability than females, even above the modal score level.

Conclusions:

  • The population distribution of general intelligence may be a mixture of two normal distributions.
  • One distribution represents typical intelligence variation, the other reflects conditions associated with mental retardation.
  • Observed sex differences in variability at the high end did not explain differences in high-level achievement.