Computer-based training (CBT) has become a common form of instructional delivery in business and educational environments. A standard practice during the design and development of CBT, is to incorporate the multimedia principle to aid learning. However, a recent meta-analysis by Pastore, Briskin, and Asino (2016) revealed that very little research has actually examined the multimedia principle (single vs. multiple representations) on adult learners in a computer-based environment. Instead, much of the research has focused on K-12, used paper and pencil rather than a computer, did not compare single vs multiple representations, or had methodological issues (i.e. did not report the type of knowledge assessed). As a result, the current study examines the multimedia, modality, and redundancy principles in a computer-based environment with adult learners on learning (high-and low-level knowledge) and cognitive load measures. The results of the low (recall) and high (transfer) level learning tasks in this study supported the multimedia principle. Multiple representations were found to better support learning than just one. However, this was not the case for modality or redundancy principles. Learners presented duplicate text and narration or text with optional narration performed just as well as those with no duplication, indicating reverse redundancy. Additionally, the narration and images groups did not outperform text and image groups.