Active learning methodologies have been used to teach science, technology, engineering, arts and mathematics at higher education institutions in several countries. We report the results of using peer instruction in an Astronomy undergraduate course taught at a research university in Brazil. The course syllabus covered topics on astrometry and celestial mechanics at an introductory level and was offered in the second semester of 2018. In order to better investigate the effect of the interaction among students, we have asked them to talk to their peers after the first poll regardless of the outcome. We have then analyzed the outcomes of all peer instruction polls, before and after student interaction, as well as the course evaluation questionnaires answered by the students at the end of the semester. From these analyses we were able to establish an approximation between peer instruction and some key elements of Vygotsky’s social interactionist theory.
