  Modeling Instruction (MI), an active-learning introductory physics
curriculum, has been shown to improve student academic success. Peer-to-peer
interactions play a salient role in the MI classroom. Their impact on student
interest and self-efficacy -- preeminent constructs of various career theories
-- has not been thoroughly explored. Our examination of three undergraduate MI
courses (N=221) revealed a decrease in students' physics self-efficacy, physics
interest, and general science interest. We found a positive link from physics
interest to self-efficacy, and a negative relationship between science interest
and self-efficacy. We tested structural equation models confirming that student
interactions make positive contributions to self-efficacy. This study frames
students' classroom interactions within broader career theory frameworks and
suggests nuanced considerations regarding interest and self-efficacy constructs
in the context of undergraduate active-learning science courses.
