Occupational Context Moderates the Association Between Agreeableness and Brain Structure

ABSTRACT Background Previous research on associations between personality traits and brain structure has yielded inconsistent findings, suggesting that such relationships may depend on contextual factors. Methods This study examined whether occupational context moderates the association between agreeableness and gray matter volume (GMV). Structural MRI data were obtained from 175 healthy working adults. GMV was quantified using the Gray Matter Brain Healthcare Quotient (GM‐BHQ), and personality traits were assessed using the Ten‐Item Personality Inventory. Participants were classified into knowledge workers and non‐knowledge workers. Hierarchical regression analyses were conducted controlling for demographic, lifestyle, psychological variables, and recruitment source. Results A significant interaction between agreeableness and occupational context was observed. Among knowledge workers, agreeableness was positively associated with whole‐brain GMV, whereas among non‐knowledge workers, it was negatively associated with GMV. These associations remained significant after adjustment for covariates. Exploratory analyses suggested similar patterns across multiple brain regions. Conclusions The association between personality traits and brain structure may vary depending on occupational context. However, given the cross‐sectional design and sample characteristics, these findings should be interpreted as associative rather than causal.