The default mode network (DMN), typically studied with PET and fMRI, has inconsistent support in EEG research. This study tested whether blind decomposition methods could identify DMN-like spatial patterns in EEG data across traditional frequency bands, and whether those patterns relate to task demands. Data were collected during rest, an explicit facial affect judgment task, and a social game task. Only alpha band patterns overlapped substantially with the DMN and correlated with DMN-related functions. Spontaneous self-referential thoughts during rest were linked to enhanced alpha activity in the posterior DMN hub, while processing external stimuli disrupted this activity and caused partial alpha phase-locking. This suggests alpha oscillations primarily synchronize internal mental processes rather than processing external stimuli.
Cultural mindsets, whether individualistic or collectivistic, can be temporarily activated through priming and influence brain connectivity and social behavior. After collectivism priming, self-related thoughts were linked to increased connectivity between the default mode network (DMN) and the right temporoparietal junction, a region involved in perspective-taking. After individualism priming, such thoughts were linked to increased connectivity with the temporal pole, involved in self/other discrimination. Individual differences in the intensity of self-related thoughts and DMN-temporal pole connectivity after priming predicted behavior in a social interaction task: an individualistic mindset predisposed individuals to more friendly and trustful behavior.