Supplementary file 1_When more isn’t better: evidence for an instructional equivalence hypothesis in multimedia design.docx

Pedagogical theories suggest that effective multimedia can reduce extraneous cognitive load and help students create mental models of new learning. Theoretically derived and empirically supported design principles are widely assumed to improve learning outcomes, but most of the principles have been studied in relative isolation. This study was conducted as a strong test of multimedia design for learning controlling for content and pedagogy. We presented participants with short educational videos using three different multimedia formats: Rich multimedia, sparse multimedia, and no multimedia. Despite the strong theoretical and empirical foundations for this experiment, there was no significant effect of multimedia design on learning outcomes, F(2, 126) = 0.52, p = 0.60, ηp2 = 0.008. Need for Cognition scores were measured and included as a covariate; however, they did not significantly predict performance across conditions, F(1, 63) = 0.25, p = 0.62, ηp2 = 0.004. Contrary to expectation, multimedia design had no measurable impact on student learning. To account for this pattern, we introduce the Instructional Equivalence Hypothesis—the proposal that when content and pedagogy are effective and internally aligned, the format of multimedia presentation may be functionally interchangeable. This framework challenges a central assumption of the multimedia learning literature and invites a reevaluation of how design principles are theorized, tested, and applied in educational settings.

教学理论指出，有效的多媒体教学可降低额外认知负荷，并帮助学生构建新知识的心理模型。经理论推导与实证支撑的设计原则被广泛认为可改善学习成果，但现有研究大多对这些原则进行了相对孤立的检验。本研究旨在严格检验学习场景下的多媒体设计效果，同时控制内容与教学法变量。我们为被试呈现了采用三种不同多媒体形式的简短教学视频：丰富型多媒体（Rich multimedia）、精简型多媒体（sparse multimedia）以及无多媒体形式。尽管本实验具备坚实的理论与实证基础，但多媒体设计对学习成果并无显著影响（F(2, 126) = 0.52, p = 0.60, ηp² = 0.008）。本研究纳入了认知需求量（Need for Cognition）得分作为协变量，但该变量并未显著预测不同实验条件下的任务表现（F(1, 63) = 0.25, p = 0.62, ηp² = 0.004）。与预期相悖的是，多媒体设计并未对学生学习产生可观测的影响。为解释这一结果，我们提出教学等效假说（Instructional Equivalence Hypothesis）——即当教学内容与教学法均具备有效性且内部一致时，多媒体呈现形式可实现功能层面的互换。该框架对多媒体学习领域的核心假设提出了挑战，并呼吁重新审视教育场景中设计原则的理论构建、检验与应用方式。