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

  title={Sex Differences in Variability in General Intelligence: A New Look at the Old Question},
  author={Wendy Johnson and Andrew D. Carothers and Ian J. Deary},
  journal={Perspectives on Psychological Science},
  pages={518 - 531}
The idea that general intelligence may be more variable in males than in females has a long history. In recent years it has been presented as a reason that there is little, if any, mean sex difference in general intelligence, yet males tend to be overrepresented at both the top and bottom ends of its overall, presumably normal, distribution. Clear analysis of the actual distribution of general intelligence based on large and appropriately population-representative samples is rare, however… Expand
A Role for the X Chromosome in Sex Differences in Variability in General Intelligence?
  • W. Johnson, A. Carothers, I. Deary
  • Psychology, Medicine
  • Perspectives on psychological science : a journal of the Association for Psychological Science
  • 2009
The expected ratios of males to females at various points in the distribution are explored and the proportion of variance in general intelligence potentially due to genes on the X chromosome is estimated, providing clues to the extent to which biologically based sex differences could be manifested in the environment as sex differences in displayed intellectual abilities. Expand
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It is a paradox that males have a larger average brain size than females, that brain size is positively associated with intelligence, and yet numerous experts have asserted that there is no sexExpand
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Results on mean score differences support the hypothesis that there are no significant gender differences in cognitive ability, and the unusual results regarding differences in variance and the male-female proportion in the tails require more complex investigations. Expand


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Abstract Why are males over-represented at the upper extremes of intelligence? One possibility for which there is some empirical support is that variance is greater among adult males. There is littleExpand
Consistencies in Sex Differences 1 Running Head : SEX DIFFERENCES ON THE COGNITIVE ABILITIES TEST Consistencies in Sex Differences on the Cognitive Abilities Test across Countries , Grades , and Cohorts
Recently, Strand, Deary, and Smith (2006) reported sex differences for over 320,000 students 11-12 years old on the Cognitive Abilities Test. Although mean differences were small, score distributionsExpand
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In 1992, it was reported by Ankney and Rushton that males have larger average brain size than females even when allowance is made for body size. It is known that brain size is associated withExpand
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  • C. Burt
  • Psychology, Medicine
  • British journal of psychology
  • 1957
This paper argues that, provided samples are sufficiently large and complete, frequency-curves obtained exhibit small but significant deviations from strict normality, and, for most practical purposes, resulting distributions can be treated as approximately normal. Expand
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There is scientific and popular dispute about whether there are sex differences in cognitive abilities and whether they are relevant to the proportions of men and women who attain high-levelExpand
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