Instructor-generated videos have become a popular way to engage students with material before a class, yet this is a relatively unexplored area of research. There is support for the use of videos in which instructors tutor students, but few studies have been conducted within the context of a classroom. In this study, conducted in a large-enrollment college physiology course, we used a randomized crossover design to compare the impact of two types of instructor-generated videos that students watched as part of their preclass assignments. We compared videos featuring only an instructor (instructor-only videos) with videos featuring an instructor tutoring a student (instructor-tutee videos). We analyzed student survey responses and weekly physiology quiz scores and found that students preferred, enjoyed, and valued the instructor-only videos significantly more than the instructor-tutee videos. In contrast to prior literature, students with a grade point average (GPA) below the median (3.49) performed significantly better on physiology quizzes after watching instructor-only videos compared with instructor-tutee videos. Students with a GPA at or above the median performed equivalently on physiology quizzes after watching instructor-only or instructor-tutee videos. We present this study as an example of bringing cognitive science studies into the context of a real physiology classroom.