Augmented Reality (AR) in vocational education: A Study on two principles of the Cognitive Theory of Multimedia Learning (CTML) in AR and their effects on students' cognitive load, learning performance, and motivation

This study investigates the applicability of two key principles from the cognitive theory of multimedia learning (CTML) — the modality principle and the redundancy principle — in augmented reality (AR). While these principles have been extensively studied in traditional multimedia settings, their effectiveness in immersive technologies, such as AR, remains largely unexplored. Using a between-subjects design with three instructional conditions (audio-only, text-only, and audio and text combined), this study examined how different instructional modalities in AR influence cognitive load, learning performance, and motivation. A total of 104 apprentices from various vocational fields participated in the experiment, which involved learning a T-shirt folding technique using Microsoft HoloLens 2 AR goggles. The results demonstrated that the expected advantages of audio over text (modality principle) and the disadvantages of redundant information (redundancy principle) were not observed in AR as they typically are in traditional multimedia environments, with no differences in intrinsic or extraneous cognitive load across the three conditions. However, the study found significant relationships between cognitive load and motivation; that is, higher perceived extraneous cognitive load was associated with lower perceived motivation levels, while higher perceived germane cognitive load correlated strongly with increased perceived motivation. Learning performance analysis suggested a trend favoring audio-based instruction (either alone or combined with text) over text-only instruction, although these differences did not reach statistical significance. The findings indicate that the established CTML principles may operate differently in AR learning environments, highlighting the need for further investigation of these principles in AR. Additionally, the strong relationship identified between cognitive load and motivation highlights the importance of considering motivational factors when designing AR-based learning experiences. These results have important implications for the design of AR-based instructional materials, particularly in vocational education settings where procedural knowledge acquisition is crucial.