High fluid intelligence and analogical reasoning

Abstract

High fluid intelligence enables high performance in cognitive tasks. Hitherto, previous research on the cerebral correlates of fluid intelligence was restricted to studying participants of average fluid intelligence solving intelligence test items of varying difficulty, thus not allowing assumptions on interindividual differences in fluid intelligence. Other neuroimaging studies compared participants with varying levels of fluid intelligence but often utilised tasks that do not exclusively demand fluid intelligence. The geometric analogical reasoning task demands fluid intelligence very purely and thus is an eligible approach for research on interindividual differences in fluid intelligence. As previous findings in this field had been scant, we examined the cerebral correlates of geometric analogical reasoning in a first study and showed the involvement of parietal and frontal brain regions. This is in line with the assumptions of the parieto-frontal integration theory (P-FIT) of intelligence and with what the literature reports for verbal analogical reasoning tasks and for other visuo-spatial tasks. Furthermore, we found that short-term training led to improved behavioural performance. Training related decreases of brain activation are indicative of more automated processing of the task over time. Building upon these findings, we report results from a second study with high fluid intelligence (hi-fluIQ) and average fluid intelligence (ave-fluIQ) high-school students solving the geometric analogical reasoning task. Again in line with the P-FIT model, we demonstrated that the parieto-frontal network is involved in geometric analogical reasoning in both groups. However, the extent of task-related brain activation was modulated by fluid intelligence; while hi-fluIQ showed stronger involvement of parietal brain regions, avefluIQ showed stronger involvement of frontal brain regions. Our results thus