The interplay of temporal resolution power, psychometric intelligence and the coordination of mental operations

The temporal resolution power (TRP) hypothesis states that higher TRP of the brain as measured by psychophysical timing tasks leads to higher processing speed and better coordination of mental operations and, consequently, to higher general psychometric intelligence (g). In a previous study, the relation between TRP and g was completely mediated by working memory (WM) capacity measured as latent variable (LV) derived from three quite different WM tasks. This mediation provided evidence for the TRP hypothesis. The interpretation that higher TRP leads to better coordination of mental operations, however, is exacerbated by the broadness of the LV representing WM, which contained probably more WM processes apart from coordination. The present study aimed to further investigate whether the relation between TRP and g is mediated by coordination of mental operations. Stankov’s swaps task was applied to systematically increase demands on coordination across three conditions in 228 young adults. TRP was measured by three psychophysical timing tasks, g by a short-version of the Berlin Intelligence Structure (BIS) test. Using fixed-links modeling, error rates in the Swaps task could be described by two LVs representing 1) increasing demands on coordination and 2) additional processes not varying with experimental manipulation. Both Swaps-LVs and TRP correlated significantly with g. Preliminary results of mediation models revealed that the coordination LV lost its predictive power when predicting g together with TRP. TRP still directly predicted g indicating that the relation between g and coordination of mental operations relies on TRP as assumed by the TRP hypothesis