Abstract
Age-related changes in brain structure underlying executive functioning and semantic processing are well established, yet these relationships have rarely been examined within a cultural framework. Using the category fluency task (CFT), the present study investigated how age, culture, and gray matter volume (GMV) in the left dorsolateral prefrontal cortex (DLPFC), inferior frontal gyrus (IFG), inferior temporal gyrus (ITG), and medial temporal lobe (MTL) relate to cognitive performance in younger and older adults from the United States and Taiwan. Results revealed age-related differences in the left parahippocampus and cultural differences in the pars orbitalis, with no significant three-way interaction. Post-hoc analyses of right-hemisphere homologs identified additional age-related effects in the right superior frontal gyrus and cultural differences in the right pars orbitalis. Age-related patterns suggest that smaller volumes may reflect greater neural efficiency in younger adults, whereas larger volumes may support performance in older adults. Cultural differences further indicate that structural variability in semantic control regions disproportionately influences performance in Taiwanese participants, potentially reflecting differences in cognitive categorization that shape semantic retrieval. Together, these findings highlight that category fluency is influenced not only by structural brain integrity, but also by age-related neural variation and culturally shaped cognitive strategies.