Working memory updating as a mediator of the relation between temporal resolution power and psychometric intelligence

The temporal resolution power (TRP) hypothesis states that higher temporal acuity of the brain leads to better coordinated mental operations and, in turn, to better performance on tests of psychometric intelligence. Here, we examined this idea and concretized the vague construct "coordination of mental operations" through working memory (WM) updating. In 228 participants (age range: 18 to 30 years), TRP as derived from three timing tasks was significantly related to psychometric intelligence. Furthermore, WM updating was measured by Stankov's swaps task and depicted as a latent variable with increasing factor loadings to represent the increasing number of WM updates in different task conditions. WM updating correlated significantly with psychometric intelligence. In a latent mediation analysis, TRP and WM updating were still directly related to psychometric intelligence. Although the TRP-intelligence link did not substantially decrease in this model, the indirect path from TRP via WM updating to intelligence was statistically significant. This result suggests that higher TRP leads to temporally more precise mental representations in WM. Thereby, the present study provides a first answer to the question of how higher TRP translates into better performance and, eventually, to higher intelligence. Alternative views on the results are critically discussed.