<p>In the digital media era, the context in which symbolic content is presented may shape how it is understood and acted upon, yet behavioral data alone are often insufficient to distinguish the mechanisms underlying digital engagement. Using event-related potentials (ERPs), the present study examined how social media context influences the processing of national symbols and tested two competing accounts: enhanced sustained arousal versus increased online meaning-integration demands. In a within-subject design, 34 university students viewed images of national symbols embedded in simulated social media and traditional media interfaces. Relative to the traditional media context, the social media context produced greater sharing intention, higher self-reported pleasantness, arousal, and patriotic feeling, and shorter decision latencies. ERP results showed a stage-specific pattern. After controlling for edge-density differences, the early negative/N1-like effect was attenuated to marginal significance, suggesting that early differences were partly associated with perceptual load related to interface density. By contrast, the N400 was more negative in the social media context and remained significant after controlling for edge density, indicating that this effect is unlikely to be explained solely by low-level visual differences and is more consistent with increased demands for online meaning integration. The predefined LPP window did not differ between contexts, suggesting that a stronger expressive orientation does not necessarily imply enhanced sustained emotional arousal. Overall, the findings suggest that social media context may be associated with a stronger expressive orientation as well as greater online integration demands. The ERP time course provides process-level evidence for this distinction.</p>