This paper examines how diversity, equity, and inclusion (DEI), consumer psychology, and neuroscience intersect to shape audience responses to digital advertising. Drawing on research in third-space theory, social neuroscience, and parasocial interaction, it develops a framework for evaluating how advertising communicates belonging and what happens when it fails to do so. This framework is then applied to American Eagle Outfitters' 2025 campaign featuring Sydney Sweeney, titled "Sydney Sweeney Has Great Jeans." The campaign's visual and linguistic emphasis on a singular identity and inherited physical traits, centered on a "jeans/genes" wordplay, is analyzed through the lens of DEI representation, neural reward and threat systems, and third-space community dynamics. Findings suggest that while the campaign achieved significant reach, its structure limited inclusive identification, created interpretive ambiguity, and reduced the likelihood of broad emotional engagement. The paper concludes by proposing evidence-based advertising strategies that integrate authentic representation, community-oriented design, and participatory digital practices to foster stronger, more inclusive consumer connections.