Psychonomic Bulletin & Review

, Volume 3, Issue 1, pp 21–36

Brain size and cognitive ability: Correlations with age, sex, social class, and race


DOI: 10.3758/BF03210739

Cite this article as:
Rushton, J.P. & Ankney, C.D. Psychonomic Bulletin & Review (1996) 3: 21. doi:10.3758/BF03210739


Using data from magnetic resonance imaging (MRI), autopsy, endocranial measurements, and other techniques, we show that (1) brain size is correlated with cognitive ability about .44 using MRI; (2) brain size varies by age, sex, social class, and race; and (3) cognitive ability varies by age, sex, social class, and race. Brain size and cognitive ability show a curvilinear relation with age, increasing to young adulthood and then decreasing; increasing from women to men; increasing with socioeconomic status; and increasing from Africans to Europeans to Asians. Although only further research can determine if such correlations represent cause and effect, it is clear that the direction of the brain-size/cognitive-ability relationships described by Paul Broca (1824–1880), Francis Galton (1822–1911), and other nineteenth-century visionaries is true, and that the null hypothesis of no relation, strongly advocated over the last half century, is false.

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Copyright information

© Psychonomic Society, Inc. 1996

Authors and Affiliations

  1. 1.Department of PsychologyUniversity of Western OntarioLondonCanada

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