Abstract
Human intelligence differences are linked to diverse cognitive abilities and predict important life outcomes. Here we investigate the biological bases of fluid intelligence in a large sample of participants from the UK Biobank. We explore the genetic underpinnings of fluid intelligence via genome-wide association analysis (N = 108,147), and examine brain morphological correlates of fluid intelligence (N = 7, 485). Importantly, we develop novel statistical methods that enable high-dimensional co-heritability analysis, and compute high-resolution surface maps for the co-heritability and genetic correlations between fluid intelligence and cortical thickness measurements. Our analyses reveal the genetic overlap between fluid intelligence and brain morphology in predominately left inferior precentral gyrus, pars opercularis, superior temporal cortex, supramarginal gyrus, and their proximal regions. These results suggest a shared genetic basis between fluid intelligence and Broca’s speech and Wernicke’s language areas and motor regions, and may contribute to our understanding of the biological substrate of human fluid intelligence.