Human cognition is shaped by the way humans perceive and segment continuous, dynamic, complex, and multimodal perceptual input into meaningful, discrete episodes. Such events and their boundaries (transitions that separate meaningful units of experience from each other) play a crucial role in structuring memory, guiding attention, and enhancing understanding. Perceiving an event boundary – for example, triggered by changes in time, location, protagonist, goal, or social interaction – evokes updates in working memory and thereby prompts the formation of new or adaptation of existing event models. This segmentation process may thus enhance comprehension and recall by creating clear divisions between contexts, allowing individuals to better encode, retrieve, and reason about sensory experience. Events and their boundaries also influence predictive processes: within a given event, reliable forecasts can be made based on contextual continuity and abstract event schemata, but predictions become less reliable when crossing event boundaries. Recent models suggest that increased uncertainty and error in predictive processing in itself may drive the updating of event models in working memory, thus reinforcing the link between predictive processing and event segmentation. Overall, events and their boundaries serve as fundamental units of organization in cognitive processing, enabling humans to make sense of and coherently act upon a dynamic and often unpredictable world. In this symposium, we will present novel empirical and theoretical developments from psychology and cognitive science that explore the functions and mechanisms of event cognition. We will focus in particular on how boundaries affect the perception and segmentation (vs. integration) of dynamic input, how event models are formed within and across modalities, and how dynamic input, schema-based prediction, and contextual factors interplay to shape event representations and higher-level cognitive processes such as categorization, memory, and problem-solving.