Affective learning relates to students' attitudes, emotions, and feelings. This study focuses on measuring affective learning during library instruction by using a student response system. Participants were undergraduate students who received course-related library instruction for a research assignment. Students rated their confidence levels associated with finding resources before and after the library session using a student response system and again at the end of the semester using a paper survey. The results show a significant improvement in confidence levels for students receiving library instruction, suggesting that library instruction can have a positive influence on affective learning.