Clarifying the role of P-FIT in intelligence: key questions and emerging hypotheses

The development of Parieto-Frontal Integration Theory (P-FIT) represented a significant advance in the neuroscience of intelligence. Since then, numerous studies have supported its core claim that fronto-parietal networks are... [ view full abstract ]

The development of Parieto-Frontal Integration Theory (P-FIT) represented a significant advance in the neuroscience of intelligence. Since then, numerous studies have supported its core claim that fronto-parietal networks are preferentially involved in cognitive differences, however comparisons across studies reveal that precise anatomical replications tend to be elusive. This complex picture motivates a new set of questions that aim to further clarify the role of P-FIT networks in intelligence, and could better specify the necessity and stability of those relationships across individuals. A literature review identified key structural, functional, resting state, and lesion-mapping neuroimaging studies whose findings may collectively refine our account of the nature and scope of P-FIT networks in human intelligence. The resulting synthesis suggests that while studies of healthy individuals often emphasize variability in brain-ability relationships across people and samples, lesion studies support a necessary role for core P-FIT structures in psychometric g. Taken together, the extant literature supports a hybrid view of the neural organization of intelligence, wherein fronto-parietal networks may provide the core substrate for g (consistent with Spearman’s general factor model), but above and beyond which individuals may more idiosyncratically develop their own overall intelligence (e.g., consistent with sampling theory). This view in turn supports specific hypotheses regarding the potential links between P-FIT and both Cattell’s (1987) investment theory and Detterman’s (2002) systems theory of g and cognitive differentiation.