Beyond a bigger brain: Multivariable structural brain imaging and intelligence

Stuart J. Ritchie*, Tom Booth, Maria del C Valdés Hernández, Janie Corley, Susana Muñoz Maniega, Alan J. Gow, Natalie A. Royle, Alison Pattie, Sherif Karama, John M. Starr, Mark E. Bastin, Joanna M. Wardlaw, Ian J. Deary

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    73 Citations (Scopus)


    People with larger brains tend to score higher on tests of general intelligence (g). It is unclear, however, how much variance in intelligence other brain measurements would account for if included together with brain volume in a multivariable model. We examined a large sample of individuals in their seventies (n= 672) who were administered a comprehensive cognitive test battery. Using structural equation modelling, we related six common magnetic resonance imaging-derived brain variables that represent normal and abnormal features-brain volume, cortical thickness, white matter structure, white matter hyperintensity load, iron deposits, and microbleeds-to g and to fluid intelligence. As expected, brain volume accounted for the largest portion of variance (~12%, depending on modelling choices). Adding the additional variables, especially cortical thickness (+~5%) and white matter hyperintensity load (+~2%), increased the predictive value of the model. Depending on modelling choices, all neuroimaging variables together accounted for 18-21% of the variance in intelligence. These results reveal which structural brain imaging measures relate to g over and above the largest contributor, total brain volume. They raise questions regarding which other neuroimaging measures might account for even more of the variance in intelligence.

    Original languageEnglish
    Pages (from-to)47-56
    Number of pages10
    Publication statusPublished - Jul 2015


    • Brain
    • G-factor
    • Intelligence
    • MRI
    • Structural equation modelling

    ASJC Scopus subject areas

    • Experimental and Cognitive Psychology
    • Arts and Humanities (miscellaneous)
    • Developmental and Educational Psychology


    Dive into the research topics of 'Beyond a bigger brain: Multivariable structural brain imaging and intelligence'. Together they form a unique fingerprint.

    Cite this