The Cognitive Design Layer: A Machine-Executable Framework for Cognition-Aligned Multimedia Interface Design

Video, as a learning medium, presents a structural problem: temporal transience. As content disappears before it can be processed or integrated with existing knowledge, learners bear the full cognitive cost of navigation, retrieval, and context maintenance — work unaddressed by three decades of source-layer design optimisation.This paper introduces the Cognitive Design Layer (CDL), a machine-executable framework that applies principles from four cognitive science traditions — Cognitive Load Theory, the Cognitive Theory of Multimedia Learning, Distributed Cognition Theory, and Epistemic ActionTheory — at the interaction layer of multimedia interfaces. The CDL transforms unstructured, transient video into a structured, persistent information substrate by redistributing extraneous cognitive load to the interface, freeing working memory for higher-order synthesis.The paper presents YouNote as a reference implementation demonstrating real-time application of the CDL's principles, and outlines an empirical research agenda for evaluating the framework's effects on retention, comprehension, and knowledge velocity. This work establishes the interaction layer as a distinct and previously neglected locus for multimedia learning research, and proposes a generalisable architecture for cognition-aligned interface design.