This dissertation investigates the role of multimedia applications in enhancing student engagement in higher education, with a particular focus on the dynamics of asynchronous discussion forums and lurking behaviors. Leveraging multimedia applications facilitates dynamic, inquiry-based discussions that promote deeper cognitive engagement and learning. Despite the potential benefits, current higher education practices often fail to optimally integrate discussion forums with video learning content, the structure and nature of the online discussion seem play an important role in its effectiveness. Through two empirical studies, this research explores the impact of discussion types, the strategic placement of multimedia content, and the nuances of lurking behaviors on student engagement and learning outcomes. Study 1 validates the Lurking Engagement Survey (LES), distinguishing lurking behaviors across superficial to deep cognitive levels using the ICAP framework. It identifies lurking as a multifaceted behavior influenced by personal, technological, and social factors. Study 2 examines the interplay of discourse modes and position layouts in multimedia learning environments, revealing no significant effects on learning outcomes but highlighting the importance of aligning multimedia design with learners' prior knowledge and task structure. The findings challenge prevailing assumptions about the effectiveness of spatial contiguity in multimedia learning and suggest that other factors, such as learner characteristics and content complexity, play more crucial roles. This dissertation contributes to educational literature by offering a nuanced understanding of lurking, not merely as passive participation but as an agentic, context-dependent form of engagement. It underscores the variability of lurking behaviors across educational contexts, advocating for educational strategies that recognize and leverage both visible and invisible forms of engagement to enhance learning efficacy. Practical implications of this research include the need for instructional designs that accommodate various forms of engagement and align multimedia elements with individual learning needs. Future research directions are suggested, focusing on the exploration of additional contextual factors and the development of methodological innovations to measure lurking more effectively. Overall, this dissertation advances our understanding of multimedia learning environments in higher education, providing valuable insights into the complex dynamics of student engagement and the strategic design of learning interactions. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]