Neurophysiological mechanisms of fluid intelligence: Insights from ERP and aperiodic activity in adolescents.

To investigate the neurophysiological mechanisms of fluid intelligence (Gf), this study systematically examined neural activity differences between adolescents with high and low Gf using three core executive function (EF) tasks: inhibitory control (Flanker), working memory (4-back), and cognitive flexibility (task-switching), with a focus on event-related potentials (ERPs) and aperiodic activity. Electroencephalography (EEG) was recorded during both resting and task states, and the FOOOF algorithm was used to perform parametric spectral decomposition. The results revealed that the low-Gf group exhibited significantly larger P3 amplitudes across the Flanker, 4-back, and task-switching paradigms, a pattern consistent with the neural efficiency hypothesis and suggesting that Gf-related differences are primarily manifested in late-stage cognitive resource integration processes. Regarding aperiodic activity, group differences were task-specific. Notably, only in the Flanker paradigm did the high-Gf group exhibit a significantly larger aperiodic offset under the incongruent condition compared to the congruent condition, suggesting greater sensitivity in neural-state regulation when conflict demands increase. In contrast, the low-Gf group showed no significant difference in aperiodic offset between the two conditions, suggesting relatively limited condition-related adjustment of neural state across conflict conditions. By integrating conventional EEG measures with aperiodic components, this study provides multifaceted evidence for understanding the neural resource allocation and neural-state regulation associated with Gf and offers novel insights into the neurophysiological mechanisms underlying adolescent cognitive processing.