Is student learning from a video lecture affected by whether the instructor wears a mask?

This study examined whether having the instructor wear a mask during a video lecture affects learning. In Experiment 1, college students watched an instructional video on the formation of lightning, in which an instructor who either did or did not wear a mask as she stood next to slides and lectured. Learners' learning outcomes did not differ significantly, but learners spent significantly less time looking at the instructor's face when she was masked. In Experiment 2, using a 2 (the instructor wore a mask or not) x 2 (slides were displayed or not) between-subject design, college students learned about the process of water cycle from instructional videos. There was a significant interaction in which adding slides improved learning outcomes with a masked instructor, but not with an unmasked instructor. Adding a mask lowered student ratings of social presence with the instructor. Practical and theoretical implications are discussed.