Multimedia theory has generated a number of principles and guidelines to support computer-based training (CBT) design. However, the cognitive processes responsible for learning, from which these principles and guidelines stem from, are only indirectly derived by focusing on cognitive learning outcome differences. Unfortunately, the effects that cognitive processes have on learning are based on the assumption that cognitive learning outcomes are indicative of certain cognitive processes. Such circular reasoning is what prompted this dissertation. Specifically, this dissertation looked at the notion of referential connections, which is a prevalent cognitive process that is thought to support knowledge acquisition in a multimedia CBT environment. Referential connections, and the related cognitive mechanisms supporting them, are responsible for creating associations between verbal and visual information; as a result, their impact on multimedia learning is theorized to be far reaching. Therefore, one of the main goals of this dissertation was to address the issue of indirectly assessing cognitive processes by directly measuring referential connections to (a) verify the presence of referential connections, and (b) to measure the extent to which referential connections affect cognitive learning outcomes. To achieve this goal, a complete review of the prevalent multimedia theories was brought fourth. The most important factors thought to be influencing referential connections were extracted and cataloged into variables that were manipulated, fixed, covaried, or randomized to empirically examine the link between referential connections and learning. Specifically, this dissertation manipulated referential connections by varying the temporal presentation of modalities and the color coding of instructional material. Manipulating the temporal presentation of modalities was achieved by either presenting modalities simultaneously or sequentially. Color coding manipulations capitalized on pre-attentive highlighting and pairing of elements (i.e., pairing text with corresponding visuals). As such, the computer-based training varied color coding on three levels: absence of color coding, color coding without pairing text and corresponding visual aids, and color coding that also paired text and corresponding visual aids. The modalities employed in the experiment were written text and static visual aids, and the computer-based training taught the principles of flight to naive participants. Furthermore, verbal and spatial aptitudes were used as covariates, as they consistently showed to affect learning. Overall, the manipulations were hypothesized to differentially affect referential connections and cognitive learning outcomes, thereby altering cognitive learning outcomes. Specifically, training with simultaneously presented modalities was hypothesized to be superior, in terms of referential connections and learning performance, to a successive presentation, and color coding modalities with pairing of verbal and visual correspondents was hypothesized to be superior to other forms of color coding. Finally, it was also hypothesized that referential connections would positively correlate with cognitive learning outcomes and, indeed, mediate the effects of temporal contiguity and color coding on learning. A total of 96 were randomly assigned to one of the six experimental groups, and were trained on the principles of flight. The key construct of referential connections was successfully measured with three methods. Cognitive learning outcomes were captured by a traditional declarative test and by two integrative (i.e., knowledge application) tests. Results showed that the two multimedia manipulation impacted cognitive learning outcomes and did so through corresponding changes of related referential connections (i.e., through mediation). Specifically, as predicted, referential connections mediated the impact of both temporal contiguity and color coding on lower- and higher-level cognitive learning outcomes. Theoretical and practical implications of the results are discussed in relation to computer-based training design principles and guidelines. Specifically, theoretical implications focus on the contribution that referential connections have on multimedia learning theory, and practical implications are brought forth in terms of instructional design issues. Future research considerations are described as they relate to further exploring the role of referential connections within multimedia CBT paradigms.