Working memory involvement in reaction time and its contribution to fluid intelligence: An examination of individual differences in reaction-time distributions

Reaction-Time (RT) and Working-Memory (WM) are both correlated with fluid intelligence (GF). Prior work exploring the within-participant RT distributions shows (a) that the rate of exceptionally slow responses (indexed by the Tau parameter of the ex-Gaussian distribution) increases with WM-load, and (b) that individual differences in Tau are correlated with individual differences in WM. In the present individual-differences examination, we show that the correlation between Tau and GF was higher for tasks with an increased WM-load, i.e., with arbitrary (hence, novel) stimulus-response mapping. The results suggest that, when low-GF individuals perform reaction-time tasks with multiple novel and arbitrary stimulus-response rules, their reaction-time distribution is characterized by relatively frequent exceptionally slow responses.