Fractionating Human Intelligence

SummaryWhat makes one person more intellectually able than another? Can the entire distribution of human intelligence be accounted for by just one general factor? Is intelligence supported by a single neural system? Here, we provide a perspective on human intelligence that takes into account how general abilities or “factors” reflect the functional organization of the brain. By comparing factor models of individual differences in performance with factor models of brain functional organization, we demonstrate that different components of intelligence have their analogs in distinct brain networks. Using simulations based on neuroimaging data, we show that the higher-order factor “g” is accounted for by cognitive tasks corecruiting multiple networks. Finally, we confirm the independence of these components of intelligence by dissociating them using questionnaire variables. We propose that intelligence is an emergent property of anatomically distinct cognitive systems, each of which has its own capacity.

► We propose that human intelligence is composed of multiple independent components ► Each behavioral component is associated with a distinct functional brain network ► The higher-order “g” factor is an artifact of tasks recruiting multiple networks ► The components of intelligence dissociate when correlated with demographic variables