Openness to Experience Modulates the Neural Dynamics of Semantic Processing.

Personality fundamentally shapes language processing, yet the neurocognitive mechanisms underlying this relationship remain poorly understood. Openness to Experience (openness), as measured by the NEO Five-Factor Inventory (NEO-FFI), has been associated with enhanced creativity and engagement with novel semantic information. This study examined how openness modulates neural dynamics of semantic processing using event-related potentials (ERPs) during a semantic category verification task. Participants evaluated category relatedness across four levels of semantic structure, including high typicality (HT), low typicality (LT), related violations (RV), and nonrelated violations (NRV). Neural responses exhibited the expected graded pattern, with N400 amplitudes increasing as semantic relatedness decreased. Critically, higher Openness was associated with greater N400 differentiation between related and nonrelated violations, an effect uniquely predicted by Openness beyond the remaining four personality traits. Follow-up analyses revealed that this differentiation was primarily driven by enhanced N400 responses to nonrelated violations rather than by reduced responses to related violations. This pattern is inconsistent with a simple facilitation account in which higher Openness uniformly eases semantic processing. Instead, it suggests that Openness is associated with heightened sensitivity to semantic mismatch or more sustained semantic evaluation when incoming information is incompatible with an activated context. Behavioral performance was comparable across participants; the observed neural differences were not accompanied by detectable differences in task success. Together, these findings establish that Openness is systematically related to variation in the neural dynamics of semantic processing, while highlighting the need to clarify the underlying cognitive mechanisms and contributions of other individual differences.