In 4 experiments, participants viewed a short video-based lesson about how the Doppler effect works. Some students viewed already-drawn diagrams while listening to a concurrent oral explanation, whereas other students listened to the same explanation while viewing the instructor actually draw the diagrams by hand. All students then completed retention and transfer tests on the material. Experiment 1 indicated that watching the instructor draw diagrams (by viewing the instructor's full body) resulted in significantly better transfer test performance than viewing already-drawn diagrams for learners with low prior knowledge (d = 0.58), but not for learners with high prior knowledge (d = -0.24). In Experiment 2, participants who watched the instructor draw diagrams (by viewing only the instructor's hand) significantly outperformed the control group on the transfer test, regardless of prior knowledge (d = 0.35). In Experiment 3, participants who watched diagrams being drawn but without actually viewing the instructor's hand did not significantly outperform the control group on the transfer test (d = -0.16). Finally, in Experiment 4, participants who observed the instructor draw diagrams with only the instructor's hand visible marginally outperformed those who observed the instructor draw diagrams with the instructor's entire body visible (d = 0.36). Overall, this research suggests that observing the instructor draw diagrams promotes learning in part because it takes advantage of basic principles of multimedia learning, and that the presence of the instructor's hand during drawing may provide an important social cue that motivates learners to make sense of the material.